Enterobacteriacea

J Food Prot, 2001 Nov, 64(11), 1756 - 60
Shellac formulations to reduce epiphytic survival of coliform bacteria on citrus fruit postharvest; McGuire RG et al.; Survival of the coliform bacteria Enterobacter aerogenes and Escherichia coli was monitored in a neutral carboxymethylcellulose formulation and in shellac formulations with various pH and concentrations of ethanol and the preservative paraben; populations were subsequently measured from the surface of citrus fruit coated with these formulations . Numbers of the two bacteria increased over 24 h from 10(6) CFU/ml to approximately 10(8) CFU/ml in the carboxymethylcellulose solution, but over this time numbers remained little changed in the neutral solution of shellac . The Enterobacter was more tolerant of alcohol over a 3-h period: although its numbers in a shellac solution with 10% ethanol dropped from more than 10(6) CFU/ml to just over 10(3) CFU/ml . E . coli and a third species . Klebsiella pneunoniae, declined toward the limit of detection (5 CFU/ ml) during this time . The addition of morpholine to increase the formulation pH to 9.0 caused numbers of bacteria to plummet to an undetectable level within 30 to 60 min . On Ruby Red grapefruit and Valencia oranges in storage at 13 degrees C numbers of E . aerogenes and E . coli declined over 2 weeks from 10(5) CFU/cm2 to less than 2.5 x 10(1), but most of the loss in numbers occurred within 1 day . Numbers remained significantly less on shellacked fruit compared with those applied in the carboxymethylcellulose coating, and a shellac coating prepared from a pH 9 solution was more toxic to these species than one in which 12% ethanol had been added to the neutral formulation.The addition of the preservative paraben in the basic shellac was further inhibitory.

Tohoku J Exp Med, 2001 Aug, 194(4), 205 - 12
Enterobacterial repetitive intergenic consensus sequence-based PCR (ERIC-PCR); its ability to differentiate Streptococcus pyogenes strains and applicability to the study of outbreaks of streptococcal infection; Matsumoto M et al.; We evaluated the ability of enterobacterial repetitive intergenic consensus sequence-based PCR (ERIC-PCR) to differentiate 95 Streptococcus pyogenes strains with M or T serotypes isolated from sporadic streptococcal infections as compared with M or T serotypings and pulsed-field gel electrophoresis (PFGE) . Although the ERIC-PCR had less discriminatory power, defined as the ability to divide the strains with the same serotypes into the different sub-types, than PFGE, it consistently classified the strains into 16 patterns with a high correlation with M or T serotyping . The PCR method further discriminated 4 M or T serotypes into sub-types . The application of ERIC-PCR to 5 outbreaks of streptococcal infection produced the results that agreed closely with those of T serotyping and PFGE . ERIC-PCR has sufficient discriminatory power and is a quick and relatively easy technique, making it useful for routine epidemiological investigations.

Transfusion, 2001 Nov, 41(11), 1356 - 64
Multiplex PCR for detection of Enterobacteriaceae in blood; Sen K et al.; BACKGROUND: Rapid and sensitive methods are needed to detect the small numbers of bacteria that may sometimes contaminate units of blood during collection . A multiplex 5'-nuclease TaqMan PCR assay (PE Applied Biosystems) was used to detect several bacterial species that may contaminate blood . STUDY DESIGN AND METHODS: Oligonucleotide primers were made for regions of the 16S rRNA gene conserved in four different bacterial species: Yersinia enterocolitica and Serratia, Klebsiella, and Enterobacter species . Two probes were designed: SL-1 detected Serratia, Klebsiella, and Enterobacter species, and YE-3 detected Y . enterocolitica . RESULTS: When TaqMan PCR was performed with chromosomal DNA isolated from pure cultures of Serratia liquefaciens, Klebsiella oxytoca, Klebsiella pneumoniae, Enterobacter cloacae, and Enterobacter agglomerans, the limit of detection with probe SL-1 was 1 to 2 CFUs . For S . marcescens, the sensitivity was 8 CFUs . The limit of detection for Y . enterocolitica with probe YE-3 was 2 CFUs . When total chromosomal DNA was extracted from whole-blood samples spiked with different numbers of Y . enterocolitica, S . liquefaciens, E . cloacae, or K . pneumoniae bacteria, the TaqMan PCR detected 12 to 16 organisms in 1 mL of blood . CONCLUSION: The 5'-nuclease TaqMan PCR assay takes only 3 hours to perform and has the potential to detect very small numbers of bacteria.

Acta Microbiol Pol, 2001, 50(2), 161 - 7
Cloning of enterohemorrhagic Escherichia coli phage VT-2 dam methyltransferase; Radlinska M et al.; Enterobacterial GATC-specific DNA adenine methyltransferase (Dam) plays an essential role in regulation of DNA replication, methyl-directed mismatch repair, transposition and gene expression . In Salmonella typhimurium it has been shown to directly control virulence . In this paper we report cloning and expression of the dam gene from the Shiga toxin-producing VT2-Sa prophage of enterohemorrhagic Escherichia coli O157 . Comparisons of the predicted amino acid sequence indicates that Dam methyltransferases of E . coli phages VT2-Sa, 933W, T1 and Haemophilus influenzae phage HP1 make up a separate subgroup of adenine-N6 methyltransferases . These proteins are similar to the gamma subfamily of amino-methyltransferases in respect to the linear order of sequence motifs and the presence of the hallmark "NPPY" tetrapeptide . However, they apparently lack an autonomous target-recognizing domain at the C-terminus of the catalytic domain and therefore we propose to dub them as a "mini-gamma" subfamily.

Pharmacotherapy, 2001 Aug, 21(8), 920 - 8
Extended-spectrum beta-lactamases: epidemiology, detection, and treatment; Nathisuwan S et al.; Extended-spectrum beta-lactamases (ESBLs) are extremely broad spectrum beta-lactamase enzymes found in a variety of Enterobacteriaceae . Most strains producing these beta-lactamases are Klebsiella pneumoniae, other Klebsiella species (i.e., K . oxytoca), and Escherichia coli . When producing these enzymes, organisms become highly effective at inactivating various beta-lactam antibiotics . In addition, ESBL-producing bacteria are frequently resistant to many classes of antibiotics, resulting in difficult-to-treat infections . Other problems due to ESBL-producing bacteria are difficulty in detecting the presence of ESBLs, limited treatment options, and deleterious impact on clinical outcomes . Clinicians should be familiar with the clinical significance of these enzymes and potential strategies for dealing with this growing problem.

New Microbiol, 2001 Oct, 24(4), 365 - 9
Staphylococci in orthopaedic surgical wounds; Arciola CR et al.; From 50 infected surgical wounds of orthopaedic patients, 43 (86%) staphylococcal strains were isolated . 34 of all these staphylococci belonged to Staphylococcus aureus species (i.e . 68 % of all isolates from surgical wounds; 79% of staphylococcal isolates); 9 were coagulase-negative staphylococci (i.e . 21% of all isolates from surgical wounds; 18% of staphylococcal isolates) . Among microorganisms isolated from the wounds we also found 2 (4%) of the Enterobacteriaceae family; 2 (4%) of the Pseudomonas genus; 3 (6%) of the Streptococcus genus . Thus, orthopaedic surgical wounds were infected by staphylococci (mainly S . aureus) more frequently than by other micro-organisms . All the staphylococcal strains were screened for methicillin resistance by agar disk diffusion testing and for the presence of mecA gene responsible for methicillin resistance by PCR . 32% of the S . aureus and 33% of the S . epidermidis strains resulted methicillin resistant and mecA-positive . The data confirm the diffusion of methicillin resistant S . aureus in surgical site infections and shows that the so-called "new pathogens", i.e . S . epidermidis and other coagulase-negative staphylococci, also exhibit a frequent and hazardous methicillin-resisting ability.

Proc Natl Acad Sci U S A, 2001 Dec 4, 98(25), 14607 - 12 Epub 2001 Nov 20.
Mutation frequency and biological cost of antibiotic resistance in Helicobacter pylori; Bjorkholm B et al.; Among the several factors that affect the appearance and spread of acquired antibiotic resistance, the mutation frequency and the biological cost of resistance are of special importance . Measurements of the mutation frequency to rifampicin resistance in Helicobacter pylori strains isolated from dyspeptic patients showed that approximately 1/4 of the isolates had higher mutation frequencies than Enterobacteriaceae mismatch-repair defective mutants . This high mutation frequency could explain why resistance is so frequently acquired during antibiotic treatment of H . pylori infections . Inactivation of the mutS gene had no substantial effect on the mutation frequency, suggesting that MutS-dependent mismatch repair is absent in this bacterium . Furthermore, clarithromycin resistance conferred a biological cost, as measured by a decreased competitive ability of the resistant mutants in mice . In clinical isolates this cost could be reduced, indicating that compensation is a clinically relevant phenomenon that could act to stabilize resistant bacteria in a population.

J Hosp Infect, 2001 Nov, 49(3), 183 - 92
A simultaneous outbreak on a neonatal unit of two strains of multiply antibiotic resistant Klebsiella pneumoniae controllable only by ward closure; Macrae MB et al.; Two aminoglycoside-resistant strains of Klebsiella pneumoniae caused an outbreak on the neonatal unit at St Thomas' Hospital . One, which affected 18 patients, was capsular type K18 and resistant to newer cephalosporins by the production of the extended-spectrum beta-lactamase SHV-2; the other, which colonized four patients, was capsular non-typeable and did not produce extended-spectrum beta-lactamase . Both strains were probably brought into the unit by carrier patients; the probable carrier of the non-typeable strain was transferred from another hospital but was negative on a single admission screen; the probable carrier of the K18 strain was not screened on admission because he had been born at St Thomas', but his mother had been transferred from another hospital . Despite intensive efforts to control the outbreak by standard methods of hand washing, screening, patient isolation and environmental cleaning, a total of 22 neonates on the unit eventually became colonized or infected . One of three patients with bacteraemia died . A small proportion of samples of expressed breast milk, electronic thermometers and oxygen saturation probes were contaminated by the K18 strain and may have contributed to some of the cross-infection, but this did not explain the extent of the outbreak . The outbreak was controlled only by opening a temporary ward for colonized neonates and another for newly born babies, which allowed the closure and cleaning of the main neonatal unit . Multiply antibiotic resistant klebsiellas may be highly epidemic and cause serious, difficult-to-control outbreaks on neonatal units . All patients, regardless of their admission history, should be screened on admission for carriage of multiply resistant enterobacteria by a sensitive method, and units should have plans for temporary ward closure should outbreaks occur .

J Hosp Infect, 2001 Nov, 49(3), 173 - 82
Molecular epidemiological typing of Enterobacter cloacae isolates from a neonatal intensive care unit: three-year prospective study; Fernandez-Baca V et al.; Since 1992, there has been an increase in the incidence of Enterobacter sepsis in the neonatal intensive care unit (NICU) of the authors' hospital . From 1995 to 1997, a prospective molecular epidemiological survey of the colonizing and infecting strains isolated from neonates was conducted . Enterobacter cloacae was the most frequent cause of neonatal sepsis, accounting for 19.2% of all neonatal infections, reaching a peak incidence of 2.2/1000 during 1996 . Fifty isolates from the NICU and four epidemiologically unrelated strains were characterized by pulse-field gel electrophoresis (PFGE), ribotyping, enterobacterial repetitive intergenic consensus (ERIC)-PCR and plasmid profiling . PFGE was the most discriminatory technique and identified 13 types (two of them classified into two and three subtypes) compared with ERIC-PCR, plasmid profiling and ribotyping that identified 11, 11 and seven types, respectively . A good correlation was found between all techniques . Five different clones caused 15 cases of sepsis . Clones A and B were prevalent in 1995 and 1996, but they were not isolated in 1997 . An outbreak caused by clone G in 1997 was controlled by cohort nursing and hygienic measures, without changing the antibiotic policy . Strains were characterized by their antibiotic resistance pattern and divided into three groups . Group I correlated with PFGE types A, B1 and B2, which hyperproduced Bush type 1 chromosomal beta-lactamase and expressed extended-spectrum ?-lactamases (ESBLs) . Group II only hyperproduced Bush type 1 chromosomal beta-lactamase and correlated with PFGE-types D1, D2, D3 and I . Finally, Group III, with inducible beta-lactamases, correlated with the rest of PFGE types . The sudden disappearance of E . cloacae after reinforcement of hygienic measures confirms the importance of patient-to-patient transmission .

Eur J Clin Microbiol Infect Dis, 2001 Sep, 20(9), 626 - 35
Multicenter evaluation of an automated system using selected bacteria that harbor challenging and clinically relevant mechanisms of resistance to antibiotics; Leclercq R et al.; A multicenter study was carried out to evaluate the performance of a new commercial automated system in comparison with that of the reference agar dilution method . Ten clinical microbiology laboratories tested a collection of 61 strains of gram-negative bacilli (49 Enterobacteriaceae and 12 Pseudomonas aeruginosa), and 6 other laboratories tested a collection of 55 strains of gram-positive cocci (10 enterococci and 45 staphylococci) against 10-20 antimicrobial agents . The strains were selected on the basis that they harbored challenging and characterized mechanisms of resistance . In comparison with the agar reference method, the automated system gave an overall essential agreement (+/-1 dilution) of 94.5%, 93.5%, and 97% for the gram-negative bacilli, enterococci, and staphylococci, respectively . According to the interpretive standards of the National Committee for Clinical Laboratory Standards, the category agreement ranged from 96 to 96.4% for the three sets of organisms . The accuracy of the automated system, as determined by the kappa test, ranged from 0.80 to 0.88, reflecting an almost perfect agreement with the reference technique . Very major, major, and minor errors obtained with the automated system were 0.3%, 2.9%, and 6.6% for gram-negative bacilli, 3.4%, 0%, and 5% for enterococci, and 1%, 1.6%, and 2.7% for staphylococci, respectively . The high rate of very major errors in enterococci was mostly due to a single strain of multidrug-resistant Enterococcus faecium, which was found susceptible to several antibiotics in a majority of participant laboratories . The use of a heavy inoculum and of a broth test medium by the automated system might account for a better expression of certain resistance mechanisms, including beta-lactamases, as compared to the agar dilution reference method . The interlaboratory reproducibility was acceptable, as shown by the narrow dispersion of MICs and by the results of quality control.

Int J Antimicrob Agents, 2001 Nov, 18(5), 451 - 61
AS-924, a novel, orally active, bifunctional prodrug of ceftizoxime: physicochemical properties, oral absorption in animals, and antibacterial activity; Mori N et al.; AS-924 is an oral prodrug of the antibiotic ceftizoxime (CTIZ), a parenteral use cephalosporin . This novel prodrug, produced by esterifying CTIZ with a lipophilic pivaloyloxymethyl (POM) group and introducing a water soluble L-alanyl group, is expected to increase the bioavailability and thereby, augment the antibacterial activity of CTIZ in vivo compared with existing prodrugs . To study the effect of the L-alanyl group in AS-924 on its bioavailability, the plasma concentration profiles of CTIZ in dogs were examined following the dosing of AS-924 and CTIZ-POM, in powder form, after pretreatment with the antacid ranitidine, and following the dosing of AS-924 after pretreatment with a gastrointestinal motility stimulant metoclopramide or suppressant scopolamine butylbromide . The absorption rate of AS-924 was constant under these different conditions due to its unique balance of lipophilicity and water solubility . CTIZ is as antibacterially active as pre-existing oral cephalosporins against Gram-positive clinical isolates, while being more active against all Gram-negative isolates-particularly Enterobacteriaceae and Haemophilus influenzae . A simulation model for the eradication profile of bacteria in computer programmed pharmacokinetic (PK) system was carried out to study the antibacterial action of CTIZ in human . CTIZ was proven to eradicate Streptococcus pneumoniae and H . influenzae effectively, while cefpodoxime (CPOD), the active moiety of CPOD proxetil, eradicated S . pneumoniae, but not H . influenzae . These results confirm that, AS-924 is a potent oral antibiotic and would be expected to be clinically effective and efficient.

Antimicrob Agents Chemother, 2001 Dec, 45(12), 3595 - 8
Characterization of a chromosomally encoded extended-spectrum class A beta-lactamase from Kluyvera cryocrescens; Decousser JW et al.; A chromosomally located beta-lactamase gene, cloned and expressed in Escherichia coli from a reference strain of the enterobacterial species Kluyvera cryocrescens, encoded a clavulanic acid-inhibited Ambler class A enzyme, KLUC-1, with a pI value of 7.4 . KLUC-1 shared 86% amino acid identity with a subgroup of plasmid-mediated CTX-M-type extended-spectrum beta-lactamases (CTX-M-1, -3, -10, -11, and -12), the most closely related enzymes, and 77% amino acid identity with KLUA-1 from Kluyvera ascorbata . The substrate profile of KLUC-1 corresponded to that of CTX-M-type enzymes.

Microbiology, 2001 Nov, 147(Pt 11), 3105 - 11
Occurrence of two superoxide dismutases in Aeromonas hydrophila: molecular cloning and differential expression of the sodA and sodB genes; Leclere V et al.; Aeromonas spp., considered as emerging opportunistic pathogens, belong to the family Vibrionaceae . Among the criteria currently used for their classification is the presence of a single FeSOD (iron-containing superoxide dismutase), which distinguishes them from Enterobacteriacea . In this paper the cloning of the sodA and sodB genes encoding two different SODs in Aeromonas hydrophila ATCC 7966 is reported . The sodB gene encoded an FeSOD (196 amino acids, 21.5 kDa), was constitutively expressed and showed 75% homology with the E . coli FeSOD . The sodA gene encoded a protein of 206 amino acids (22.5 kDa) with MnSOD (manganese-containing SOD) activity and showed 55% homology with the Escherichia coli MnSOD . The MnSOD of A . hydrophila was detected only during the stationary phase of growth under high aeration or when induced by lack of iron . Nevertheless, paraquat had no detectable effect on its production . The amino-terminal part of the Mn-containing protein contained a putative signal sequence which could permit a periplasmic localization.

Microbiology, 2001 Nov, 147(Pt 11), 3015 - 25
Conserved amino acid residues found in a predicted cytosolic domain of the lipopolysaccharide biosynthetic protein WecA are implicated in the recognition of UDP-N-acetylglucosamine; Amer AO et al.; WecA, an integral membrane protein that belongs to a family of polyisoprenyl phosphate N-acetylhexosamine-1-phosphate transferases, is required for the biosynthesis of O-specific LPS and enterobacterial common antigen in Escherichia coli and other enteric bacteria . WecA functions as an UDP-N-acetylglucosamine (GlcNAc):undecaprenyl-phosphate GlcNAc-1-phosphate transferase . A conserved short sequence motif (His-Ile-His-His; HIHH) and a conserved arginine were identified in WecA at positions 279-282 and 265, respectively . This region is located within a predicted cytosolic segment common to all bacterial homologues of WecA . Both HIHH279-282 and the Arg265 are reminiscent of the HIGH motif (His-Ile-Gly-His) and a nearby upstream lysine, which contribute to the three-dimensional architecture of the nucleotide-binding site among various enzymes displaying nucleotidyltransferase activity . Thus, it was hypothesized that these residues may play a role in the interaction of WecA with UDP-GlcNAc . Replacement of the entire HIHH motif by site-directed mutagenesis produced a protein that, when expressed in the E . coli wecA mutant MV501, did not complement the synthesis of O7 LPS . Membrane extracts containing the mutated protein failed to transfer UDP-GlcNAc into a lipid-rich fraction and to bind the UDP-GlcNAc analogue tunicamycin . Similar results were obtained by individually replacing the first histidine (H279) of the HIHH motif as well as the Arg265 residue . The functional importance of these residues is underscored by the high level of conservation of H279 and Arg265 among bacterial WecA homologues that utilize several different UDP-N-acetylhexosamine substrates.

Microbiology, 2001 Nov, 147(Pt 11), 2951 - 9
Molecular comparison of pathogenic bacteria from pear trees in Japan and the fire blight pathogen Erwinia amylovora; Kim WS et al.; Several strains of the genus Erwinia, which were isolated in Japan from pear trees with necrotic symptoms that resembled fire blight, and tentatively identified as Erwinia amylovora, were reinvestigated for their relationship to the fire blight pathogen . These isolates produced ooze on slices of immature pears and were mucoid on MM2Cu agar plates, but did not synthesize levan and did not give the expected PCR signals with several primer pairs specific for Erwinia amylovora . The isolates tested positive with PCR primers designed to detect the novel pear pathogen Erwinia pyrifoliae, which was isolated from Nashi pear trees in South Korea . The nucleotide sequence analysis of a DNA fragment preceding the gene cluster for exopolysaccharide synthesis revealed a closer relationship to Erwinia pyrifoliae than to Erwinia amylovora . Plasmid profiles, protein patterns and genomic DNA analysed by PFGE after XbaI and SpeI digestion were different than Erwinia amylovora . Experiments with strains of Erwinia amylovora isolated from raspberry (Rubus sp.), Erwinia mallotivora and Enterobacter pyrinus also did not reveal a relationship between these bacteria and the Japanese Erwinia strains . The latter are not identical to Erwinia pyrifoliae, but possess many similar features to this pathogen that causes Asian pear blight . It is concluded that pathogenic bacteria isolated in Japan from pear trees with symptoms resembling fire blight are possibly different from Erwinia amylovora.

J Bioenerg Biomembr, 2001 Jun, 33(3), 179 - 86
The Na+-translocating NADH:quinone oxidoreductase (NDH I) from Klebsiella pneumoniae and Escherichia coli: implications for the mechanism of redox-driven cation translocation by complex I; Steuber J; Eukaryotic complex I integrated into the respiratory chain transports at least 4 H+ per NADH oxidized . Recent results indicate that the cation selectivity is altered to Na+ in complex I (NDH I) isolated from the enterobacteria Escherichia coli and Klebsiella pneumoniae . A sequence analysis illustrates the characteristic differences of the enterobacterial, Na+-translocating NDH I compared to the H+-translocating complex I from mitochondria . Special attention is given to the membranous NuoL (ND5, Nqo12) subunits that possess striking sequence similarities to secondary Na+/H+ antiporters and are proposed to participate in Na+ transport . A model of redox-linked Na+ (or H+) transport by complex I is discussed based on the ion-pair formation of a negatively charged ubisemiquinone anion with a positively charged Na+ (or H+).

Ther Umsch, 2001 Oct, 58(10), 609 - 13
{Nosocomial pneumonia}; Ewig S et al.; Nosocomial pneumonia is a frequent complication, particularly during mechanical ventilation . Microbial patterns differ according to the time of onset: whereas early onset pneumonia (up to the fourth day of hospitalization) is mostly caused by Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae, leading pathogens of late onset pneumonia (after the fourth day) additionally include gram-negative Enterobacteriaceae and potentially drug resistant microorganisms . These general patterns are modified in the presence of specific individual risk factors . The diagnostic work-up of pneumonia is aimed at the assessment of severity, the confirmation of the presence of pneumonia as well as the identification of the causal pathogens . The results of microbiological investigations must always be interpreted in the clinical context . Antimicrobial treatment must always be initiated empirically based on expected microbial patterns as outlined above . Nosocomial pneumonia in nonventilated and ventilated patients requires different empirical antimicrobial treatment approaches . All patients with antimicrobial treatment failures must be comprehensively reevaluated.

Int J Antimicrob Agents, 2001 Oct, 18(4), 365 - 71
Detection of amp C in Enterobacter cloacae in China; Zhang YL et al.; PCR amplification of 55 strains of Enterobacter cloacae indicated 51 of them had amp C structural gene verified by DNA sequence and Southern blotting . All PCR products were cleaved into 666- and 328-bp fragments by Kpn1 restriction enzyme . Imipenem was the most potent inducer for mRNA expression of amp C gene and beta-lactamase activity . The beta-Lactamase inhibitor R0481220 strongly inhibited Amp C beta-lactamases; 96.4% (53/55) of Enterobacter cloacae producing Amp C enzyme were susceptible to cefepime.

J Med Chem, 2001 Nov 8, 44(23), 4023 - 6
New pyridoquinoline derivatives as potential inhibitors of the fluoroquinolone efflux pump in resistant Enterobacter aerogenes strains; Chevalier J et al.; Enterobacter aerogenes, one of the most frequently isolated nosocomial pathogens in France, is exhibiting increasing multidrug resistance mechanisms associated with a change in membrane permeability . For drugs of the quinolone family, mutations in the target and active efflux play a prominent role in the resistance . We report here the effect of several pyridoquinoline derivatives that restore a noticeable fluoroquinolone accumulation to resistant strains that overexpress the MarA activator . Studies of the energy-dependent quinolone efflux indicate that the most efficient derivatives tested probably inhibit the resistance process by acting as substrate competitors on the pump extruding intracellular norfloxacin.

J Ind Microbiol Biotechnol, 2001 Oct, 27(4), 228 - 33
Bacterial amelioration of bauxite residue waste of industrial alumina plants; Hamdy MK et al.; The high alkali content of bauxite residue deposits from alumina production plants in industrial nations poses a challenge to reestablish flora and fauna at the deposit sites . The present study demonstrated that low levels of injured bacterial cells in the bauxite residue actively grew using various added nutrients and/or hay . The organisms grew from less than 10 to more than 10(9) cells g(-1) bauxite residue and formed organic acids that lowered the pH from 13 to about 7.0 . A total of 150 cultures was isolated from treated bauxite residue and included species of Bacillus, Lactobacillus, Leuconostoc, Micrococcus, Staphylococcus, Pseudomonas, Flavobacterium and Enterobacter . Scanning electron micrographs demonstrated that untreated particles (control) of the bauxite residue were clumped together, and in treated bauxite residue these particles were highly dispersed with microcolonial structures . Furthermore, the treated bauxite residue supported growth of several plants and earthworms that survived for over 300 days . In a test plot bioremediation on a residue deposit at Alcoa Point Comfort, TX, the Bermuda grass hay used was effective mulch material and encouraged water filtration, leading to establishment and growth of salt-tolerant vegetative species.

Diagn Microbiol Infect Dis, 2001 Sep-Oct, 41(1-2), 65 - 70
Validation of the VITEK2 and the Advance Expert System with a collection of Enterobacteriaceae harboring extended spectrum or inhibitor resistant beta-lactamases; Canton R et al.; The susceptibility testing accuracy of the VITEK2 system and the ability of the Advance Expert System (AES) to provide interpretive readings were evaluated against 86 extended spectrum (ESBL) and 6 inhibitor-resistant-TEM (IRT) beta-lactamases producing Enterobacteriaceae clinical isolates . VITEK2 MICs of 12 beta-lactams were compared with those obtained by the standard NCCLS microdilution technique . The overall essential agreement ( +/- 1 log dilution) was 87.8% . Discrepancies were mainly observed with cefepime (30.3% of total number of discrepancies), ceftazidime (21.2%), and cefotaxime (15.1%) . MIC discrepancies were slightly higher in CTX-M- (14.4%) than in TEM- (12.5%) or SHV- (11.9%) type ESBL producers and were rare in IRT producers (1.4%) . Overall interpretive agreement was 92.5% and minor, major, and very major errors were 5.4%, 1.7%, and 2.1%, respectively . The AES was able to identify an ESBL phenotype in 85 out of 86 isolates (98.8%) and an IRT phenotype in all 6 isolates harboring these enzymes, thus reducing very major errors to 0.9% . The VITEK2 system, in conjunction with the AES software, is a reliable tool for detection of ESBL or IRT producing Enterobacteriaceae isolates.

Diagn Microbiol Infect Dis, 2001 Sep-Oct, 41(1-2), 1 - 14
Cefditoren in vitro activity and spectrum: a review of international studies using reference methods; Jones RN et al.; Cefditoren, a broad-spectrum orally administered cephalosporin ester, has documented in vitro efficacy against many Gram-positive and -negative pathogens and stability against clinically important beta-lactamases . We have reviewed the microbiology and the pharmacokinetic/pharmacodynamic literature regarding the spectrum and potency of this newer agent against the major etiologic agents of community-acquired respiratory infection, (Streptococcus pneumoniae, Hemophilus influenzae and Moraxella catarrhalis), as well as the Enterobacteriaceae and non-enteric Gram-negative bacilli, staphylococci, and other aerobic and anaerobic Gram-positive cocci . The level of cefditoren activity against S . pneumoniae (MIC(90,) 0.5 microg/mL) was superior to all marketed oral cephalosporins and at least equal to amoxicillin +/- clavulanate . H . influenzae (MIC(90,) 0.016-0.03 microg/mL) and M . catarrhalis (MIC(90,) 0.06-0.5 microg/mL) were also very susceptible to cefditoren . In contrast to cefixime and ceftibuten, cefditoren was active against oxacillin-susceptible staphylococci (MIC(90,) < or = 1 microg/mL) at a level comparable to cefuroxime axetil, cefaclor or cefprozil . Enterococci, Pseudomonas aeruginosa and most anaerobes (Gram-negative) were not cefditoren-susceptible, but most Enterobacteriaceae, beta-haemolytic and viridans group streptococci were highly susceptible . Furthermore, an overview of key in vitro susceptibility testing methods and issues including disk diffusion testing and Etest (AB BIODISK, Solna, Sweden) method accuracy, interpretive criteria, and pharmacodynamic considerations for the selection of a breakpoint concentration are provided . The rapid bactericidal nature of the antibacterial activity of cefditoren, its post antibiotic effect, penicillin binding protein targets, and extent of beta-lactamase stability are all favorable qualities . In conclusion, this orally administered (BID) beta-lactam possesses promise for use against commonly isolated problematic respiratory tract pathogens such as penicillin-non-susceptible pneumococci and beta-lactamase-positive M . catarrhalis or H . influenzae . Success in the clinical trials will further define the role of cefditoren in this era of emerging resistant bacterial pathogens.

J Gastroenterol Hepatol, 2001 Oct, 16(10), 1112 - 9
Protective effect of rebamipide on indomethacin-induced intestinal damage in rats; Mizoguchi H et al.; BACKGROUND AND AIM: We evaluated the effect of rebamipide (2-(4-chlorobenzoylamino)-3-{2(1H)-quinolinon-4-yl} propionic acid), a novel anti-ulcer drug, on indomethacin-induced small intestinal lesions in rats . METHODS: The animals were administered indomethacin (10 mg/kg, s.c.), and they were killed 24 h later . Rebamipide (30-300 mg/kg) was administered p.o . twice, 30 min before, and 6 h after indomethacin . RESULTS: Indomethacin caused hemorrhagic lesions in the rat small intestine, accompanied by an increase in enterobacterial translocation, inducible nitric oxide synthase (iNOS) and myeloperoxidase (MPO) activities, as well as thiobarbituric acid (TBA) reactants, and these changes were significantly prevented by the supplementation with 16,16-dimethyl prostaglandin E2 (dmPGE2; 10 microg/kg, i.v.) or the pretreatment of animals with the antibiotic ampicillin . Treatment of the animals with rebamipide dose-dependently prevented the development of intestinal lesions, and this effect was mimicked by i.v . administration of superoxide dismutase (SOD: 3000 U/kg) + catalase (CAT: 5000 U/kg) . The protection by rebamipide was accompanied by a significant suppression of the increase in both MPO and iNOS activities, and a complete inhibition of the increase in TBA reactants, while SOD + CAT significantly inhibited the increase of MPO activity and TBA reactants, but not iNOS activity . The bacterial translocation following indomethacin was also significantly decreased by either rebamipide or SOD + CAT . CONCLUSION: These results confirmed the importance of enterobacteria and iNOS/NO in the pathogenesis of indomethacin-induced small intestinal lesions, and suggested that rebamipide prevents the development of these lesions, probably by its radical scavenging action.

Curr Microbiol, 2001 Dec, 43(6), 448 - 51
Recombinant Enterobacter amnigenus highly toxic to Anopheles dirus mosquito larvae; Khampang P et al.; The mosquito-larvicidal binary toxin of Bacillus sphaericus 2297 was expressed in Enterobacter amnigenus, a Gram-negative bacterium isolated from Anopheles dirus larvae gut . The toxin was placed under the regulation of various promoters in order to improve the expression level of the toxin . Amongst the recombinants obtained, E . amnigenus harboring pBS373, a plasmid which contains the toxin genes under the control of the native B . sphaericus promoter, expressed a significant amount of protein, comparable to that found in B . sphaericus 2297 . In addition, this recombinant provided approximately twenty times higher toxicity against second-instar Anopheles dirus larvae when compared to B . sphaericus 2297 . The procedure of obtaining this environmentally isolated bacterium from larvae gut and introducing the system for mosquito-larvicidal toxin synthesis is noteworthy . The promising result presented here provides a substantial degree of confidence for further field studies.

Clin Microbiol Infect, 2001 Oct, 7(10), 553 - 61
Trends in quinolone susceptibility of Enterobacteriaceae among inpatients of a large university hospital: 1992-98; Robert J et al.; OBJECTIVES: To assess trends in quinolone susceptibility of Enterobacteriaceae isolated in a large university hospital . METHODS: Between 1992 and 1998, bacterial isolates were collected each year during a 3-month period to evaluate annual changes in susceptibility . In addition, the activities of fluoroquinolones (pefloxacin, norfloxacin, ofloxacin, ciprofloxacin) against nalidixic acid-resistant strains were determined by disk diffusion and MIC methodologies during the first and last year of the study . RESULTS: The susceptibility of Enterobacteriaceae to nalidixic acid was unchanged between 1992 and 1998 (86% versus 85%) . However, at the species level, the susceptibility rates to nalidixic acid decreased for Escherichia coli from 92% to 89%, and for Enterobacter cloacae from 87% to 82% . In contrast, there was a 10% increase in the nalidixic acid susceptibility rates for Klebsiella pneumoniae (74% versus 83%), which was thought to be due to the control of the spread of epidemic extended-spectrum beta-lactamase (ESBL)-producing strains . The overall susceptibility of the Enterobacteriaceae to the fluoroquinolones remained high during the study period, greater than 90% in the case of ciprofloxacin . However, nalidixic acid-resistant Escherichia coli showed decreased susceptibility to ciprofloxacin between 1992 and 1998, as reflected by a decrease in median zone diameter (26 mm to 19 mm), an increase in MIC(50) (0.25 mg/L to 1 mg/L) and a shift in MIC distribution (unimodal in 1992 to bimodal in 1998) . This has resulted in the reduced susceptibility of Escherichia coli to fluoroquinolones between 1992 and 1998 (pefloxacin, 95-90%; ciprofloxacin, 99-95%) . CONCLUSIONS: The susceptibility of Escherichia coli to quinolones has decreased, and the level of susceptibility of the resistant strains has increased over the 7-year study period.

J Clin Microbiol, 2001 Nov, 39(11), 3865 - 70
PCR analyses of tRNA intergenic spacer, 16S-23S internal transcribed spacer, and randomly amplified polymorphic DNA reveal inter- and intraspecific relationships of Enterobacter cloacae strains; Clementino MM et al.; PCR analysis of tRNA intergenic spacer (tDNA-PCR) and of the 16S-23S internal transcribed spacer (ITS-PCR) and random amplified polymorphic DNA (RAPD) analysis were evaluated for their usefulness in characterization of Enterobacter cloacae strains isolated from both clinical origins and vaccine microbial contamination . tDNA-PCR presented specific and reproducible patterns for Enterobacter sakazakii ATCC 29004, Enterobacter aerogenes ATCC 13048, and Enterobacter cloacae ATCC 13047 and 23355 that presented the same profile for all 16 E . cloacae isolates, offering an alternative tool for species-level identification . ITS-PCR and RAPD analysis yielded completely different banding patterns for the 20 strains studied, except for E . cloacae strains isolated from different batches of vaccine that exhibited a unique pattern, suggesting contamination by the same strain . The combined use of tDNA-PCR and ITS-PCR in a one-step protocol allows accurate identification and typing of E . cloacae strains a few hours after the colony has been isolated.

Appl Environ Microbiol, 2001 Nov, 67(11), 5285 - 93
Endophytic colonization and in planta nitrogen fixation by a Herbaspirillum sp . isolated from wild rice species; Elbeltagy A et al.; Nitrogen-fixing bacteria were isolated from the stems of wild and cultivated rice on a modified Rennie medium . Based on 16S ribosomal DNA (rDNA) sequences, the diazotrophic isolates were phylogenetically close to four genera: Herbaspirillum, Ideonella, Enterobacter, and Azospirillum . Phenotypic properties and signature sequences of 16S rDNA indicated that three isolates (B65, B501, and B512) belong to the Herbaspirillum genus . To examine whether Herbaspirillum sp . strain B501 isolated from wild rice, Oryza officinalis, endophytically colonizes rice plants, the gfp gene encoding green fluorescent protein (GFP) was introduced into the bacteria . Observations by fluorescence stereomicroscopy showed that the GFP-tagged bacteria colonized shoots and seeds of aseptically grown seedlings of the original wild rice after inoculation of the seeds . Conversely, for cultivated rice Oryza sativa, no GFP fluorescence was observed for shoots and only weak signals were observed for seeds . Observations by fluorescence and electron microscopy revealed that Herbaspirillum sp . strain B501 colonized mainly intercellular spaces in the leaves of wild rice . Colony counts of surface-sterilized rice seedlings inoculated with the GFP-tagged bacteria indicated significantly more bacterial populations inside the original wild rice than in cultivated rice varieties . Moreover, after bacterial inoculation, in planta nitrogen fixation in young seedlings of wild rice, O . officinalis, was detected by the acetylene reduction and (15)N(2) gas incorporation assays . Therefore, we conclude that Herbaspirillum sp . strain B501 is a diazotrophic endophyte compatible with wild rice, particularly O . officinalis.

Clin Microbiol Infect, 2001 Sep, 7(9), 470 - 8
The changing nature of aminoglycoside resistance mechanisms and prevalence of newly recognized resistance mechanisms in Turkey; Over U et al.; OBJECTIVE: To determine the most frequently occurring individual and combined resistance mechanisms in Gram-negative bacteria resistant to any of the clinically available aminoglycosides in Turkey, and to compare these mechanisms with those found in smaller, earlier studies . METHODS: Aminoglycoside resistance mechanisms in Gram-negative isolates resistant to either gentamicin, tobramycin, netilmicin or amikacin collected in different regions of Turkey were evaluated both phenotypically and genotypically using 12 aminoglycosides and up to 22 aminoglycoside resistance gene probes . RESULTS: Among 696 aminoglycoside-resistant Gram-negative bacteria, resistance rates were very high for gentamicin (94.5%), tobramycin (82.4%), netilmicin (53.6%), and amikacin (49.7%) . Although isepamicin was the most active aminoglycoside against Gram-negative bacteria, increased resistance (29.7%) was found and resistance rates were higher than those in most of the other countries surveyed in earlier studies . The most common aminoglycoside resistance mechanisms (AAC(3)-II (GTN), AAC(6')-I (TNA), and ANT(2")-I (GT)) in the earlier studies were also found in the present isolates of Klebsiella spp., Enterobacter spp . and Escherichia coli, with increased complexity . In addition to these old mechanisms, two new aminoglycoside resistance mechanisms, namely AAC(6')-III (TNAI) and AAC(6')-IV (GTNA), were also found at significant frequencies (11.9% and 26.9%, respectively) in these isolates of Enterobacteriaceae (n = 435) . Among the isolates of Pseudomonas spp . (n = 150), in addition to the increased complexity of enzymatic resistance mechanisms (AAC(3)-I (16.6%), AAC(6')-II (29.3%), AAC(6')-III (19.3%), ANT(2")-I (40%)), permeability resistance seemed to be responsible for the high rates of resistance to aminoglycosides . CONCLUSION: The results of this study indicated increased resistance to clinically available aminoglycosides, including isepamicin, even though it was the most active, as a result of both the presence of new aminoglycoside resistance mechanisms and the increased complexity of all mechanisms, including permeability resistance, particularly in Pseudomonas in Turkey.

Arch Latinoam Nutr, 2001 Jun, 51(2), 173 - 9
{Microbiological stability study of minimally processed cantaloupe (Cucumis melo L) by vacuum}; Millan FR et al.; In order to design a minimal process for cantaloupe, the water activity of the fruit was reduced until 0.976 through vacuum osmotic dehydration and the optimum combination of microbial preservatives (100 ppm sodium sulfite, 600 ppm potassium sorbate, 0.5% L-ascorbic acid and 1% citric acid), that contributed to minimize (p < 0.05), the content of aerobic mesophilic bacteria, molds and yeast, was determined through a 2k multifactorial design . In the second experimental stage, the conditions previously mentioned were tested together with the application of fruit's blanching (98 degrees C/3 min) with saturated steam and product storage in three different modified atmospheres (6% O2-6% CO2, 5% O2-10% CO2 and atmospheric air) . In such sense, the application of microbial preservatives together with fruit's blanching and atmospheric air in high barrier packages (30 mu nylon) contributed to extent the shelf life of the cantaloupe minimally processed during 14 days on the basis of aerobic mesophilic bacteria, psychrotrophic bacteria, acid lactic bacteria, enterobacteria, molds, yeast and the sensory attributes color, odour, taste and texture.

Cas Lek Cesk, 2001 Aug, 140(16), 487 - 91
{New aspects of antibiotic resistance and possibilities of its prevention}; Blahova J et al.; New phenomena of the antibiotic resistance in bacteria have recently appeared . The may hold present explosive development of resistance and prevent its transferability from multiple drug resistant bacteria to still sensitive ones . They may prevent the production of so-called extended-spectrum beta-lactamases (ESBLs) among Enterobacteriaceae producing resistance virtually to all penicillins and cephalosporins with exception of those antibiotics potentiated by clavulanic acid or sulbactam, the resistance to vancomycin in enterococci and staphylococce, and the resistance of Stenotrophomonas maltophilia . Factors participating on the development of resistance include: a) transferability of resistance genes among bacteria which explosively change susceptible strains to resistant ones, b) dosage and types of antibiotics which cause the selection pressure to certain species of bacteria, c) level of organization and strict adherence to hygienic and anti-epidemic regimen starting with the entry of patients into the hospital . Analyses are necessary to check whether the patient brings resistant bacteria with a transferable resistance (with ESBLs) into the hospital . Preventive measures would be strictly applied to stop the clonal spread of resistant strains among the patients and/or hospital environment, which occurs if these strains have such opportunity . Last, but not least to be considered is the dosage, composition and rationality of administration of antibacterials, mainly in post-operative prophylaxis in intensive care units, in so-called empirical usage, etc . At the same time, it would be highly unethical to hesitate with application of antibacterials to patients when it is justified, necessary and rational . Hospital antibiotics policy should rationally decide between these alternatives in each application of antibiotics or their combinations.

J Formos Med Assoc, 2001 Aug, 100(8), 548 - 52
Comparison of ofloxacin and norfloxacin concentration in prostatic tissues in patients undergoing transurethral resection of the prostate; Chen J et al.; BACKGROUND AND PURPOSE: To compare the concentrations of two fluoroquinolones, ofloxacin (OFLX) and norfloxacin (NFLX), in the prostate glands of patients who underwent transurethral resection of the prostate (TUR-P) after oral ingestion of both drugs for surgical prophylaxis . METHODS: Ten patients with clinical symptoms of benign prostatic hyperplasia undergoing TUR-P received 200 mg of both drugs per os simultaneously 2 hours before surgery . The concentrations of the drugs in the serum and prostate at the time of surgery were measured by high performance liquid chromatography . Patients' clinical characteristics were evaluated, including findings from transrectal ultrasonography of the prostate, prostate specific antigen concentration, renal function tests, and post-operative status . RESULTS: Two hours after administration, the mean serum concentration of OFLX was 4.14 +/- 0.64 mg/L (range 0.27-6.37) and of NFLX was 1.10 +/- 0.22 mg/L (range 0.02-2.1) . The concentration of ORLX in prostatic tissue was 4.10 +/- 0.79 micrograms/g (range 1.70-6.37) and of NFLX was 2.22 +/- 0.57 micrograms/g (range 0.63-4.35) . The ratio of the prostatic tissue concentration (P) to the serum concentration (S) was 2.11 for OFLX and 5.71 for NFLX . The concentrations of both drugs exceeded the minimum inhibitory concentration (MIC) for most gram-negative organisms, but NFLX may be unable to exceed the MIC90 of Enterobacter cloacae in some individuals . Leukocytosis and spiking fever developed after TUR-P in two of the 10 patients . CONCLUSIONS: Concentrations of OFLX were higher in both serum and prostatic adenoma tissues than those of NFLX (p < 0.001), while NFLX had better penetration into the prostate (P/S ratio) (p < 0.001) . The results of this study indicated that the concentrations of both of these drugs exceeded the MIC for most gram-negative organisms.

Nature, 2001 Oct 25, 413(6858), 852 - 6
Complete genome sequence of Salmonella enterica serovar Typhimurium LT2; McClelland M et al.; Salmonella enterica subspecies I, serovar Typhimurium (S . typhimurium), is a leading cause of human gastroenteritis, and is used as a mouse model of human typhoid fever . The incidence of non-typhoid salmonellosis is increasing worldwide, causing millions of infections and many deaths in the human population each year . Here we sequenced the 4,857-kilobase (kb) chromosome and 94-kb virulence plasmid of S . typhimurium strain LT2 . The distribution of close homologues of S . typhimurium LT2 genes in eight related enterobacteria was determined using previously completed genomes of three related bacteria, sample sequencing of both S . enterica serovar Paratyphi A (S . paratyphi A) and Klebsiella pneumoniae, and hybridization of three unsequenced genomes to a microarray of S . typhimurium LT2 genes . Lateral transfer of genes is frequent, with 11% of the S . typhimurium LT2 genes missing from S . enterica serovar Typhi (S . typhi), and 29% missing from Escherichia coli K12 . The 352 gene homologues of S . typhimurium LT2 confined to subspecies I of S . enterica-containing most mammalian and bird pathogens-are useful for studies of epidemiology, host specificity and pathogenesis . Most of these homologues were previously unknown, and 50 may be exported to the periplasm or outer membrane, rendering them accessible as therapeutic or vaccine targets.

J Am Chem Soc, 2001 Oct 31, 123(43), 10436 - 43
Mechanism of inhibition of the class C beta-lactamase of Enterobacter cloacae P99 by cyclic acyl phosph(on)ates: rescue by return; Kaur K et al.; As previously described (Pratt, R . F.; Hammar, N . J . J . Am . Chem . Soc . 1998, 120, 3004.), 1-hydroxy-4,5-benzo-2,6-dioxaphosphorinone(3)-1-oxide (salicyloyl cyclic phosphate) inactivates the class C beta-lactamase of Enterobacter cloacae P99 in a covalent fashion . The inactivated enzyme slowly reverts to the active form . This paper shows that reactivation involves a recyclization reaction that regenerates salicyloyl cyclic phosphate rather than hydrolysis of the covalent intermediate . The inactivation, therefore, is a slowly reversible covalent modification of the active site . The thermodynamic dissociation constant of the inhibitor from the inactivated enzyme is 0.16 microM . Treatment of the inactivated enzyme with alkali does not produce salicylic acid but does, after subsequent acid hydrolysis, yield one molar equivalent of lysinoalanine . This result proves that salicyloyl cyclic phosphate inactivates the enzyme by (slowly reversible) phosphorylation of the active site serine residue . This result contrasts sharply with the behavior of acyclic acyl phosphates which transiently inactivate the P99 beta-lactamase by acylation (Li, N.; Pratt, R . F . J . Am . Chem . Soc . 1998, 120, 4264.) . This chemoselectivity difference is explored by means of molecular modeling . Rather counterintuitively, in view of the relative susceptibility of phosphates and phosphonates to nucleophilic attack at phosphorus, 1-hydroxy-4,5-benzo-2-oxaphosphorinanone(3)-1-oxide, the phosphonate analogue of salicyloyl cyclic phosphate, did not appear to inactivate the P99 beta-lactamase in a time-dependent fashion . It was found, however, to act as a fast reversible inhibitor (K(i) = 10 microM) . A closer examination of the kinetics of inhibition revealed that both on and off rates (9.8 x 10(3) s(-1) x M(-1) and 0.098 s(-1), respectively) were much slower than expected for noncovalent binding . This result strongly indicates that the inhibition reaction of the phosphonate also involves phosphylation of the active site . Hence, unlike the situation with bacterial DD-peptidases covalently inactivated by beta-lactams, the P99 beta-lactamase inactivated by the above cyclic acyl phosph(on)ates can be rescued by return . Elimination of the recyclization reaction would lead to more effective inhibitors.

J Immunol, 2001 Nov 1, 167(9), 5278 - 85
Differential induction of endotoxin tolerance by lipopolysaccharides derived from Porphyromonas gingivalis and Escherichia coli; Martin M et al.; Exposure of mononuclear phagocytes to enterobacterial LPS induces a state of transient hyporesponsiveness to subsequent LPS exposure, termed endotoxin tolerance . In the present study, LPS derived from the oral periodontal pathogen, Porphyromonas gingivalis, was compared with that derived from the enterobacterium, Escherichia coli, for the ability to induce endotoxin tolerance . Pretreatment of the human macrophage cell line, THP-1, with E . coli LPS resulted in a severe reduction in the levels of IL-1beta, IL-6, and TNF-alpha upon secondary stimulation . In contrast, pretreatment of THP-1 cells with P . gingivalis LPS resulted in a mitigation of IL-1beta, but not IL-6 and TNF-alpha production upon subsequent exposure to P . gingivalis LPS: primary or secondary stimulation with < or =100 ng/ml P . gingivalis LPS resulted in comparable levels of IL-6 and TNF-alpha, while stimulation of THP-1 cells with > or =1 microg/ml P . gingivalis LPS induced a significant enhancement in IL-6 and TNF-alpha levels upon secondary exposure . To identify possible mechanisms for these differences, changes in the expression of molecules involved in the LPS-signaling pathway were assessed . Pretreatment of THP-1 cells with E . coli LPS resulted in a significant reduction in surface Toll-like receptor 4 (TLR4) expression and an inability to degrade I-kappaB-alpha or I-kappaB-beta proteins upon secondary stimulation . In contrast, pretreatment of THP-1 cells with P . gingivalis LPS resulted in a significant enhancement of both CD14 and TLR2, while maintaining the ability to degrade I-kappaB-beta only upon secondary stimulation . Thus, E . coli and P . gingivalis LPS differentially affect CD14 and TLR expression as well as secondary LPS-associated responses.

J Bacteriol, 2001 Nov, 183(22), 6509 - 16
Identification of the structural gene for the TDP-Fuc4NAc:lipid II Fuc4NAc transferase involved in synthesis of enterobacterial common antigen in Escherichia coli K-12; Rahman A et al.; The polysaccharide chains of enterobacterial common antigen (ECA) are comprised of the trisaccharide repeat unit Fuc4NAc-ManNAcA-GlcNAc, where Fuc4NAc is 4-acetamido-4,6-dideoxy-D-galactose, ManNAcA is N-acetyl-D-mannosaminuronic acid, and GlcNAc is N-acetyl-D-glucosamine . Individual trisaccharide repeat units are assembled as undecaprenyl-linked intermediates in a sequence of reactions that culminate in the transfer of Fuc4NAc from TDP-Fuc4NAc to ManNAcA-GlcNAc-pyrophosphorylundecaprenol (lipid II) to yield Fuc4NAc-ManNAcA-GlcNAc-pyrophosphorylundecaprenol (lipid III), the donor of trisaccharide repeat units for ECA polysaccharide chain elongation . Most of the genes known to be involved in ECA assembly are located in the wec gene cluster located at ca . 85.4 min on the Escherichia coli chromosome . The available data suggest that the structural gene for the TDP-Fuc4NAc:lipid II Fuc4NAc transferase also resides in the wec gene cluster; however, the location of this gene has not been unequivocally defined . Previous characterization of the nucleotide sequence of the wec gene cluster in the region between o416 and wecG revealed that it contained three open reading frames: o74, o204, and o450 . In contrast, the results of experiments described in the current investigation revealed that it contains only two open reading frames, o359 and o450 . Mutants of E . coli possessing null mutations in o359 were unable to synthesize ECA, and they accumulated lipid II . In addition, the in vitro incorporation of {(3)H}FucNAc from TDP-{(3)H}Fuc4NAc into lipid II was not observed in reaction mixtures using cell extracts obtained from these mutants as a source of enzyme . The ECA-negative phenotype of these mutants was complemented by plasmid constructs containing the wild-type o359 allele, and Fuc4NAc transferase activity was demonstrated by using cell extracts obtained from the complemented mutants . Furthermore, partially purified o359 gene product, expressed as recombinant C-terminal His-tagged protein, was able to catalyze the in vitro transfer of {(3)H}Fuc4NAc from TDP-{(3)H}Fuc4NAc to lipid II . Our data support the conclusion that o359 of the wec gene cluster of E . coli is the structural gene for the TDP-Fuc4NAc:lipid II Fuc4NAc transferase involved in the synthesis ECA trisaccharide repeat units.

Pathol Biol (Paris), 2001 Sep, 49(7), 540 - 7
{Comparison of 2 administration protocols (continuous or discontinuous) of a time-dependent antibiotic, Tazocin}; Pedeboscq S et al.; A predictive parameter of beta-lactam therapeutic efficacy is the time (T > MIC) while antibiotic serum concentrations are above the MIC of suspected bacteriological agents . This led us to carry out a randomised open study to compare the usually used intermittent administration of Tazocin (three injections of 4 g/0.5 g a day) and continuous perfusion of 12 g/1.5 g a day by calculating these T > MIC . Patients from digestive reanimation department were randomised within two arms: continuous or intermittent administration . Sixteen takings of blood were executed over a forty-hour period . After liquid/liquid extraction, piperacillin and tazobactam serum concentrations were determined by HPLC with a reversed phase column (C18) and a UV spectrophotometry detection . Then, from the time-concentration curves we have evaluated the T > MIC for an enterobacteria (MIC = 8 micrograms/mL) and for Pseudomonas (MIC = 16 micrograms/mL) . Concerning intermittent administration T > MIC were 74% (c > MICenterobacteria) and 62% (c > MICPseudomonas) . These percentages in the continuous arm were 100% (c > MICenterobacteria) and 99% (c > MICPseudomonas) . Tazobactam concentrations were low and even undetectable between each injection in the intermittent administration arm . This was not found within the continuous administration arm . In conclusion, for the intermittent administration, we observed some long periods occurring before each injection while antibiotic concentrations were under the MIC of most bacteria . During these same periods tazobactam concentrations were under the efficacy threshold . These periods were not observed within the continuous administration arm.

Pathol Biol (Paris), 2001 Sep, 49(7), 515 - 21
{Spread of Enterobacteriaceae producing broad-spectrum beta-lactamase and the development of their incidence over a 16-month period in a university hospital center}; Eveillard M et al.; Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLE) constitute with methicillin-resistant Staphylococcus aureus the main multiresistant bacteria recovered in French hospitals . Our objectives were to evaluate these ESBLE diffusion in our teaching hospital and to follow their incidence during a 16-month period, whereas a control programme (barrier precautions) had been implemented in the beginning of 1999 . This study was conducted in a teaching hospital containing 1800 beds, from February 1999 to May 2000 . All ESBLE isolated in clinical or screening samples were included . Duplicates (same bacteria in the same patient) were excluded . The detection of the ESBL was performed with the double-disk diffusion test . Incidence densities were determined with their 95% confidence interval (CI95%) . Their evolution by four-month period was evaluated with the chi-square test for trend . During the 16-month period, 229 ESBLE were isolated . The incidence was 0.35 per 1000 patient-days (PD) (CI95% = {0.30-0.40}) for the whole hospital . It was 0.47/1000 PD (CI95% = {0.38-0.56}) in medical wards, 0.29/1000 PD (CI95% = {0.20-0.38}) in surgical wards and 1.32/1000 PD (CI95% = {0.90-1.74}) in intensive care units . Enterobacter aerogenes strains represented more than 75% of all ESBLE, whereas Klebsiella pneumoniae stains represented only 8.6% . During the study, the incidence of ESBLE and the proportion of strains acquired in our hospital decreased significantly (p < 0.0001 and p < 0.001 respectively) . Indeed, between the first eight-month period and the last one, the incidence of ESBLE acquired in our hospital decreased by 55%, whereas the incidence of imported strains increased slightly . This study shows that the diffusion of ESBLE concerns the entire hospital . The implementation of a control programme of the spread of multiresistant bacteria allowed us to reduce significantly the incidence of ESBLE . This incidence seemed to be stable for several months . The implementation of a policy which restricts antimicrobial use would allow us to complete the the efficacy of barrier precautions.

Clin Pharmacokinet, 2001, 40(9), 685 - 94
Clinical use of ceftriaxone: a pharmacokinetic-pharmacodynamic perspective on the impact of minimum inhibitory concentration and serum protein binding; Perry TR et al.; Ceftriaxone is a third-generation cephalosporin that is used for a variety of infections such as meningitis, gonorrhoea and community-acquired pneumonia . The most important aspects of its pharmacokinetics include a long half-life, excellent tissue penetration and saturable (dose-dependent) serum protein binding of the drug . A pharmacodynamic analysis {total area under the concentration-time curve (AUC)/minimum inhibitory concentration (MIC)} was performed in several populations (healthy volunteers, children, the elderly, and patients with renal and hepatic impairment) against various bacterial species (Streptococcus pneumoniae, the Enterobacteriacieae, methicillin-susceptible Staphylococcus aureus, and Pseudomonas aeruginosa) . AUC/MIC {area under the inhibitory time curve (AUIC)} was chosen as the pharmacodynamic parameter for this analysis since ceftriaxone is a time-dependent killer and high peak concentrations are not needed . In addition, there is a significant correlation between AUIC, time when concentration exceeds the MIC (t > MIC) and time to eradication . Total and free AUICs (assuming a free fraction = 10%) were calculated since it is highly protein bound . It was postulated that a free AUIC of at least 125 would be required to achieve efficacy . From our analysis of these various populations, we were able to conclude that the free AUIC values support the use of Ig daily in infections where MIC values are below 2 mg/L . In addition, consistent with its reported good activity against CSF organisms with MICs < or =1.0 mg/L and marginal activity against organisms with MICs > or =2.0 mg/L, we also recommend the target free AUIC values of at least 125 for patients with severe infections such as meningitis . Patients with mild infections may recover with values below 125 but they may remain at risk of the development of resistant organisms . Furthermore, it is essential to further validate these findings in patients who have received treatment, calculate AUICs and correlate these parameters with both clinical and microbiological outcomes.

Biofizika, 2001 Sep-Oct, 46(5), 885 - 93
{Regularities and cellular mechanism of spontaneous mutations in enterobacteria}; Chernoshchekov KA et al.; The regularities and a possible mechanism of the formation of spontaneous mutations in enterobacteria were studied . Possible causes and the mechanism of these processes were analyzed . It was shown that the mechanism of formation of spontaneous mutations is not related to the replication process and DNA polymerase errors . Mutations arise abruptly within 10-20 min due to a cosmophysical factor of unknown origin . It is assumed that cosmophysical radiation makes cell membranes excitable . Upon membrane pulsation, different volumes (portions) of cell substance are ejected through expanding pores . From this substance, viable heteromorphous mutant forms of colonies and cells (bio- and serum variants, L-forms, "parastrains", and new ecoforms of bacteria) are formed.

J Am Vet Med Assoc, 2001 Oct 1, 219(7), 976 - 81
Bacteremia associated with naturally occuring acute coliform mastitis in dairy cows; Wenz JR et al.; OBJECTIVE: To determine the incidence of bacteremia in dairy cows with naturally occurring acute coliform mastitis (ACM) with a wide range of disease severity . DESIGN: Cohort study . ANIMALS: 144 dairy cows with ACM from 6 herds . PROCEDURE: Cows were examined at time of identification of ACM (time 0) and classified as having mild, moderate, or severe mastitis on the basis of rectal temperature, hydration status, rumen contraction rate, and attitude . Cows were reexamined at 24 or 48 hours . Bacteriologic culturing of milk and blood (30 ml), CBC, and serum biochemical analysis were performed at each time point . Appropriate samples were obtained at a single point from herdmates without mastitis (controls) that were closely matched for lactation number and days since parturition . Blood culture results were compared among severity groups and controls by use of chi2 tests, as was outcome of an ACM episode for cows grouped by blood bacterial isolates . RESULTS: Bacteria were isolated from 52 blood samples from 46 of 144 (32%) cows with ACM, which was significantly more than control cows (11/156; 7.1%) . Group-1 isolates (Escherichia coli, Pasteurella multocida, Mannheimia haemolytica, Klebsiella pneumoniae, Enterobacter agglomerans, and Salmonella enterica serotype Typhimurium) were identified in 20 of 144 (14%) cows with ACM and 0 of 156 control cows . Group-1 isolates were identified in 4.3, 9.1, and 42% of cows classified as having mild, moderate, and severe ACM, respectively . Escherichia coli and K pneumoniae milk and blood isolates obtained from the same cow were of the same genotype . Bacillus spp were identified in 21 of 144 (15%) cows with ACM, which was significantly more than control cows (3/156; 1.9%) . Thirty-five percent of cows with a group-1 isolate died during the mastitis episode . CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that bacteremia develops in a substantial proportion of cows with ACM . Classification of severity of disease is important for establishment of effective treatment protocols; parenteral antimicrobial treatment may be indicated in cows with ACM.

Antimicrob Agents Chemother, 2001 Nov, 45(11), 3156 - 61
In vitro anti-Helicobacter pylori activity of the probiotic strain Bacillus subtilis 3 is due to secretion of antibiotics; Pinchuk IV et al.; A limited number of antibiotics can be used against Helicobacter pylori infection, and resistance jeopardizes the success of treatment . Therefore, a search for new agents is warranted . The use of probiotics to enhance gastrointestinal health has been proposed for many years, but the scientific basis of the prophylactic and therapeutic actions of probiotics has not yet been clearly delineated . Probiotic strain Bacillus subtilis 3, whose safety has previously been demonstrated, is known to have antagonistic properties against species of the family Enterobacteriaceae . In the present study, it was also found to inhibit H . pylori . The anti-H . pylori activity present in the cell-free supernatant was not related to pH or organic acid concentration . It was heat stable and protease insensitive . At least two antibiotics, detected by thin-layer chromatography (R(f) values, 0.47 and 0.85, respectively) and confirmed by high-performance liquid chromatographic analysis, were found to be responsible for this anti-H . pylori activity . All H . pylori strains tested were sensitive to both compounds . One of these compounds was identified as amicoumacin A, an antibiotic with anti-inflammatory properties . MICs for H . pylori determined in solid and liquid media ranged between 1.7 and 6.8 microg/ml and 0.75 and 2.5 microg/ml, respectively . The underestimation of MICs determined in solid medium may be due to physicochemical instability of the antibiotic under these test conditions . An additive effect between amicoumacin A and the nonamicoumacin antibiotic against H . pylori was demonstrated.

J Med Microbiol, 2001 Oct, 50(10), 865 - 9
Non-standard biological activities of lipopolysaccharide from Helicobacter pylori; Matsuyama N et al.; As assessed by the lipopolysaccharide (LPS)-specific chromogenic Limulus amoebocyte lysate (LAL) assay, Helicobacter pylori LPS extracted by the phenol-water procedure showed full potency to coagulate LAL, as did LPS from Salmonella minnesota and Escherichia coli . However, pretreatment of H . pylori LPS with polymyxin B, which easily destroys the endotoxic activity of enterobacterial LPS/lipid A, had little effect on the LAL coagulation activity, although the same treatment of E . coli LPS markedly diminished its activity . The H . pylori LPS induced very weak production of nitric oxide (NO) or tumour necrosis factor (TNF) by murine macrophages and TNF by human peripheral whole blood in vitro in comparison with S . minnesota LPS . These findings indicate that H . pylori LPS has the unique endotoxic characteristic of retaining full LAL coagulation activity with polymyxin B resistance, despite losing its endotoxic potencies such as the ability to induce NO and TNF production.

J Physiol Paris, 2001 Jan-Dec, 95(1-6), 51 - 7
Protection by aspirin of indomethacin-induced small intestinal damage in rats: mediation by salicylic acid; Takeuchi K et al.; Most of non-steroidal anti-inflammatory drugs (NSAIDs) except aspirin (ASA) produce intestinal damage in rats . In the present study, we re-examined the intestinal toxic effect of ASA in rats, in comparison with various NSAIDs, and investigated why ASA does not cause damage in the small intestine, in relation to its metabolite salicylic acid (SA) . Various NSAIDs (indomethacin; 10 mg/kg; flurbiprofen; 20 mg/kg; naproxen; 40 mg/kg; dicrofenac; 40 mg/kg; ASA; 20-200 mg/kg) were administered s.c., and the small intestinal mucosa was examined macroscopically 24 h later . All NSAIDs tested, except ASA, caused hemorrhagic lesions in the small intestine, with a decrease of mucosal PGE(2) contents . ASA did not provoke any damage, despite inhibiting (prostaglandin) PG production, and prevented the occurrence of intestinal lesions induced by indomethacin, in a dose-related manner . This protective action of ASA was mimicked by the equimolar doses of SA (17.8-178 mg/kg) . Indomethacin caused intestinal hypermotility, in preceding to the occurrence of lesion, and this event was followed by increases of enterobacterial translocation in the mucosa . Both ASA and SA prevented both the intestinal hypermotility and the bacterial translocation seen after indomethacin treatment . In addition, the protective effect of SA was not significantly influenced by either the adenosine deaminase or the adenosine receptor antagonists . Following administration of ASA, the blood SA levels reached a peak within 30 min and remained elevated for more than 7 h . These results suggest that SA has a cytoprotective action against indomethacin-induced small intestinal lesions, and this action may be associated with inhibition of the intestinal hypermotility and the bacterial translocation, but not mediated by endogenous adenosine . Failure of ASA to induce intestinal damage may be explained, at least partly, by a protective action of SA, the metabolite of ASA.

BMC Infect Dis . 2001;1(1):16 . Epub 2001 Sep 24.
The efficacy of chemical agents in cleaning and disinfection programs; Penna TC et al.; BACKGROUND: Due to the growing number of outbreaks of infection in hospital nurseries, it becomes essential to set up a sanitation program that indicates that the appropriate chemical agent was chosen for application in the most effective way . METHOD: For the purpose of evaluating the efficacy of a chemical agent, the minimum inhibitory concentration (MIC) was reached by the classic method of successive broth dilutions . The reference bacteria utilized were Bacillus subtilis var . globigii ATCC 9372, Bacillus stearothermophilus ATCC 7953, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 . The strains of Enterobacter cloacae IAL 1976 (Adolfo Lutz Institute), Serratia marcescens IAL 1478 and Acinetobactev calcoaceticus IAL 124 (ATCC 19606), were isolated from material collected from babies involved in outbreaks of infection in hospital nurseries . RESULTS: The MIC intervals, which reduced bacteria populations over 08 log10, were: 59 to 156 mg/L of quaternarium ammonium compounds (QACs); 63 to 10000 mg/L of chlorhexidine digluconate; 1375 to 3250 mg/L of glutaraldehyde; 39 to 246 mg/L of formaldehyde; 43750 to 87500 mg/L of isopropanol or ethanol; 1250 to 6250 mg/L of iodine in polyvinyl-pyrolidone complexes, 150 to 4491 mg/L of chlorine-releasing-agents (CRAs); 469 to 2500 mg/L of hydrogen peroxide; and, 2310 to 18500 mg/L of peracetic acid . CONCLUSIONS: Chlorhexidine showed non inhibitory activity over germinating spores . A . calcoaceticus, was observed to show resistance to the majority of the agents tested, followed by E . cloacae and S . marcescens.

Clin Infect Dis, 2001 Nov 1, 33(9), 1462 - 8 Epub 2001 Oct 04.
Parallel analysis of individual and aggregated data on antibiotic exposure and resistance in gram-negative bacilli; Harbarth S et al.; To evaluate the potential bias of analyzing aggregated data, we separately examined antibiotic exposure and resistance data for 35,423 patients admitted to a university hospital in Utah, from both an individual-patient perspective and group-level perspective . From 1994 through 1998, use of defined daily doses (per 1000 patient-days) of fluoroquinolones, third-generation cephalosporins, ampicillin-sulbactam, and imipenem increased by 82%, 38%, and 99%, and decreased by 38%, respectively, whereas group-level resistance rates of Enterobacteriaceae or Pseudomonas species changed only minimally . However, in individual-patient-level analyses performed by multivariable proportional hazards regression, exposure to a fluoroquinolone, third-generation cephalosporin, ampicillin-sulbactam, or imipenem was a strong risk factor for resistance to fluoroquinolones (adjusted hazard ratio {AHR}, 4.0; P<.001), third-generation cephalosporins (AHR, 3.5; P<.001), ampicillin-sulbactam (AHR, 2.3; P=.008), or imipenem (AHR, 5.7; P<.001), respectively . Thus, group-level and individual-patient-level analyses of antibiotic-use-versus-susceptibility relations yielded divergent results . Multicenter studies should include individual-patient-level data to elucidate more fully the relation between antibiotic exposure and resistance.

J Spinal Cord Med, 2001 Summer, 24(2), 96 - 100
Bacteremia after spinal cord injury in initial versus subsequent hospitalizations; Waites KB et al.; BACKGROUND: Individuals with spinal cord injury (SCI) have a high lifelong risk for systemic infection . For optimal therapy, it is important to characterize the organisms involved in bacteremic episodes and the sites of primary infection . The increase in drug-resistant bacteria in recent years underscores the importance of gathering accurate microbiological information . METHODS: We performed a retrospective study of hospitalized people with SCI using a computerized Microbiology Laboratory Database . We compared the microbiology of bacteremic episodes during initial versus unplanned subsequent hospitalizations . Data were collected on 55 bacteremic episodes in 30 people during initial hospitalization for SCI and 50 episodes in 29 people who were rehospitalized . RESULTS: Among cases in which a site of origin could be identified, the respiratory tract was the origin of the majority of bacteremias during initial hospitalizations, and the urinary tract was the primary origin during rehospitalizations . Polymicrobial bacteremia occurred in 14 of 55 (25%) initial versus 14 of 50 (28%) subsequent hospitalization episodes . The most common pathogens were coagulase-negative staphylococci, followed by Staphylococcus aureus and Enterobacteriaceae . Bacteremia was more common in people with tetraplegia and complete neurologic lesions than in those with paraplegia and incomplete lesions . One person in the rehospitalization group died from complications of bacteremia . All others were successfully treated . CONCLUSIONS: This study describes the frequency and characteristics of bacteremia during initial and subsequent hospitalizations following SCI and examines differences in original sites of infection . This information should be considered when planning infection control measures and empiric antibiotic regimens for patients with SCI.

Clin Microbiol Rev, 2001 Oct, 14(4), 933 - 51, table of contents
Extended-spectrum beta-lactamases in the 21st century: characterization, epidemiology, and detection of this important resistance threat; Bradford PA; Beta-lactamases continue to be the leading cause of resistance to beta-lactam antibiotics among gram-negative bacteria . In recent years there has been an increased incidence and prevalence of extended-spectrum beta-lactamases (ESBLs), enzymes that hydrolyze and cause resistance to oxyimino-cephalosporins and aztreonam . The majority of ESBLs are derived from the widespread broad-spectrum beta-lactamases TEM-1 and SHV-1 . There are also new families of ESBLs, including the CTX-M and OXA-type enzymes as well as novel, unrelated beta-lactamases . Several different methods for the detection of ESBLs in clinical isolates have been suggested . While each of the tests has merit, none of the tests is able to detect all of the ESBLs encountered . ESBLs have become widespread throughout the world and are now found in a significant percentage of Escherichia coli and Klebsiella pneumoniae strains in certain countries . They have also been found in other Enterobacteriaceae strains and Pseudomonas aeruginosa . Strains expressing these beta-lactamases will present a host of therapeutic challenges as we head into the 21st century.

Arch Pediatr, 2001 Sep, 8 Suppl 4, 721s - 725s
{Severe neonatal bacterial infections}; Saizou C et al.; The prognosis of septicemic forms of early and late neonatal sepsis is severe with a high rate of mortality especially in premature infants . The evaluation of severity is difficult because of the non specificity of the clinical signs and mortality seems to be a good means of evaluation . A study was conducted in France on the mortality due to infection in neonatal intensive care units and neonatology wards during the third trimester 2000 . Among 18 units, the mortality rate was 9.3% of admissions, corresponding to 11 early onset sepsis and 17 nosocomial infections . Death in primitive infections is essentially due to group B streptococci and E . coli with a more important risk in low gestational age infants . The nosocomial infections arise almost only in premature infant . Prognosis of infections due to Staphylococcus coagulase negative staphylococci, most frequent pathogens is good but mortalities rate is higher for enterobacteriacae--40% and for Pseudomonas, 62%.

Arch Pediatr, 2001 Sep, 8 Suppl 4, 697s - 704s
{Impact of bacterial resistance on severe infections}; Raymond J et al.; Since many years, the antimicrobial resistance increases as well as for community-acquired as for nosocomial infections . Antibiotic-resistant pneumococci are neither more nor less virulent susceptible strains . Except for immunocompromised patients, the outcome of penicillin-resistant pneumococcal infections have been similar to those in patients who are infected by susceptible ones . Current levels of S . pneumoniae resistance to penicillin and cephalosporin are not associated to an increase in mortality in children with meningitis if adequate doses of antibiotics are given . Because empiric therapy has changed, antibiotic resistance has not been associated with increased mortality . This statement can be extended to Meningococcus, for which 32 to 50% of the strains have a decreased susceptibility to penicillin . For nosocomial infections, S . aureus is the main studied pathogen . Several studies report that in patients with severe diseases (bacteremia or pneumonia) methicillin resistance of S . aureus had no significant impact on patient outcome after adjustment for different confounders . The main risk factor for mortality is the severe underlying diseases rather than the resistance as well for methicillin--resistant S . aureus, as for vancomycin resistant enterococci, Klebsiella with extended spectrum beta lactamase and Enterobacters . Recommendations for controlling epidemiologic surveillance, using barrier precautions and limiting the use of antibiotics as well in the hospital as in the community must be undertaken.

Ophthalmology, 2001 Oct, 108(10), 1830 - 4
Bacillus cereus keratitis associated with contact lens wear; Pinna A et al.; OBJECTIVE: We report the first case of contact lens-related Bacillus cereus keratitis and ulcer associated with B . cereus contamination of the contact lens case . This is also the first study to investigate and establish the genetic identity of an organism isolated from the cornea and contact lens case in a patient with contact lens-associated keratitis . DESIGN: Case report . INTERVENTION AND TESTING: Conjunctival swabs and corneal scrapings from the left eye were inoculated for culture . The contact lens case was also cultured . Antibiotic susceptibility testing was determined by agar disk diffusion method . Initial treatment with topical ciprofloxacin and fortified tobramycin was given . Genetic analysis of the bacterial isolates was performed using polymerase chain reaction (PCR) with enterobacterial repetitive intergenic consensus primers (ERIC; ERIC-PCR) . Susceptibility of B . cereus to heat and contact lens disinfecting solutions containing hydrogen peroxide, hydrogen peroxide-catalase, polyquaternium-1, and polyaminopropyl biguanide (PAPB) was tested . MAIN OUTCOME MEASURES: Clinical features, culture results, and antibiotic susceptibility testing were analyzed . The ERIC-PCR amplification products were visualized in ethidium bromide-stained agarose gel . Bacterial growth after exposure to heat and contact lens disinfecting solutions was assessed on blood agar plates . RESULTS: B . cereus was grown from the conjunctiva, corneal ulcer, and contact lens case . All isolates were sensitive to gentamicin, tobramycin, ciprofloxacin, clindamycin, and vancomycin . The corneal ulcer gradually healed over the next 6 days . Results of ERIC-PCR showed that the isolates from the cornea and contact lens case were indistinguishable, thus demonstrating the source of infecting organism to be the contaminated contact lens case . Exposure to a temperature of 80 degrees C for 20 minutes and incubation with hydrogen peroxide-catalase, polyquaternium-1, and PAPB for the minimum recommended time failed to kill B . cereus . Only exposure to hydrogen peroxide for 4 hours eradicated the organism . CONCLUSIONS: B . cereus should be considered a possible etiologic agent of contact lens-associated keratitis . Heat and many types of contact lens disinfecting solutions may be ineffective in eradicating B . cereus from contaminated contact lens cases . Only prolonged exposure to hydrogen peroxide appeared to be sporicidal to B . cereus in this study.

Diagn Microbiol Infect Dis, 2001 Aug, 40(4), 199 - 201
Enzymatic characterization of TEM-63, a TEM-type extended spectrum beta-lactamase expressed in three different genera of Enterobacteriaceae from South Africa; Hanson ND et al.; The extended-spectrum beta-lactamase, TEM-63, was identified in three separate genera of South African isolates: Proteus mirabilis, Klebsiella pneumoniae, and Escherichia coli . This paper describes identification of the gene in these isolates and compares relative rates of hyrolysis between TEM-63 and other known ceftazidimases.

Diagn Microbiol Infect Dis, 2001 Aug, 40(4), 179 - 86
Evaluation of E test, disk diffusion and broth microdilution to establish tentative quality control limits and review susceptibility breakpoints for two aerobic actinomycetes; Tomlin P et al.; A single laboratory study was carried out to compare E Test with broth microdilution and disk diffusion to establish tentative quality control ranges for Nocardia asteroides ATCC 19247 and Rhodococcus equi ATCC 6939 against a panel of eight antimicrobial agents . Reproducibility testing was performed on 12 consecutive days to establish tentative quality control ranges . A total of 36 clinical strains of the Nocardia asteroides complex and 5 Rhodococcus strains were used in the study . Both candidate control strains and clinical strains grew well on cation-adjusted Mueller-Hinton agar . Adequate growth occurred at 48 to 72 h for the Nocardia isolates and 24 to 48 h for Rhodococcus . A standardized primary inoculum of 5 x 10(4) CFU/mL was used for performance of E Test and disk diffusion for the Nocardia isolates . Tentative population-based error rates were calculated using current breakpoints for Enterobacteriaceae for E Test compared with disk diffusion for the 36 clinical strains of Nocardia species . Significant very major error rates were observed for imipenem (22%) and minor error rates varied from 2.7% to 50% . These methods require more extensive validation before definitive breakpoint criteria can be established.

Diagn Microbiol Infect Dis, 2001 Aug, 40(4), 173 - 7
In vitro antimicrobial activity of GAR-936 tested against antibiotic-resistant gram-positive blood stream infection isolates and strains producing extended-spectrum beta-lactamases; Biedenbach DJ et al.; GAR-936, a new, semisynthetic glycylcycline, has shown good antibacterial activity against a wide range of clinically important Gram-positive and -negative aerobic bacteria including Streptococcus pneumoniae, Hemophilus influenzae, Moraxella catarrhalis, Neisseria gonorrhoeae, most Enterobacteriaceae, Staphylococcus aureus and Enterococcus spp . The purpose of this study was to determine the activity of GAR-936 against a range of Gram-positive and -negative bloodstream isolates including many strains producing extended-spectrum beta-lactamases (ESBLs) . Six hundred four bloodstream isolates of Gram-positive cocci collected as part of the SENTRY surveillance program were selected for their geographic diversity . GAR-936 was also tested against an additional 176 Gram-negative cocci isolates (Klebsiella pneumoniae, 98 strains; Escherichia coli, 78 strains), 96 of which were ESBL-producers . Broth microdilution testing was used to determine the susceptibility of the selected organisms and a range of comparator antimicrobial agents whose choice was based on their activities against the selected pathogens and included a mix of both newer and older agents . Presence of an ESBL-producing strain was confirmed using the clavulanate test . GAR-936 demonstrated impressive activity against all 604 strains of Gram-positive cocci, with an MIC range of <or=0.015-1 microg/mL, and MIC(90)s ranging from <or=0.05 microg/mL for S . pneumoniae to 0.25 for S . aureus and coagulase-negative staphylococci . MICs against the 176 Gram-negative isolates were higher (range 0.06-4 microg/mL), with MIC(90)s of 0.25-1 microg/mL . The activity of GAR-936 was relatively unaffected by the presence of ESBLs . The activity of GAR-936 was particularly impressive against Gram-positive cocci when compared against the test results for vancomycin and the newer antimicrobial agents, linezolid and quinupristin/dalfopristin . The MIC(90)s for GAR-936 were significantly lower than the comparator agents for all species tested with particularly impressive results against S . pneumoniae and enterococci.

J Microbiol Methods, 2001 Nov, 47(2), 243 - 7
Performance of Pseudomonas CFC-selective medium in the fish storage ecosystems; Tryfinopoulou P et al.; Pseudomonas agar base supplemented with cephaloridine, fucidin, and cetrimide (CFC) was used to count Pseudomonas populations on fish . Both Enterobacteriaceae and Shewanella putrefaciens were able to grow on the CFC medium . Evaluation of the performance of CFC-selective for pseudomonads medium, on fish samples stored aerobically and under a modified atmosphere at 0, 10 and 20 degrees C was tested.The selectivity of the medium was affected by storage temperatures and the type of packaging of the fish samples . The selectivity of the medium diminished as the population increased and for samples stored at high temperature (20 degrees C) or under modified atmospheres.When designing adequate selectivity of a medium, interfering organisms should be taken into account, especially when the background flora tends to be more robust than the organisms to be counted or detected.

J Microbiol Methods, 2001 Nov, 47(2), 209 - 17
Rapid duplex PCR assay for the detection of pathogenic Yersinia enterocolitica strains; Aarts HJ et al.; For the detection of pathogenic Yersinia enterocolitica strains, a duplex PCR has been developed based on differences observed between the fingerprint profiles of pathogenic and non-pathogenic strains . The profiles were obtained by using a primer derived from the Enterobacterial Repetitive Intergenic Consensus (ERIC) sequences . From the sequence of one pathogen-specific amplified fragment, a discriminative primer has been designed bridging the sequence of the highly conserved core region and 3' end of the ERIC element . In combination with three other primers, all located within the detected open reading frame that resembled the sequence of the bipA gene, this primer was applied in a duplex PCR assay to simultaneously detect Y . enterocolitica and to discriminate between pathogenic and non-pathogenic strains . The same primer combinations were used in an on line rapid cycling real-time PCR assay . The used SYBR Green I format allowed for the easy translation of the PCR conditions and confirmation of the resulting amplicons . The time of analysis was reduced to approximately 60 min.

Can J Microbiol, 2001 Aug, 47(8), 698 - 705
Involvement of gacS and rpoS in enhancement of the plant growth-promoting capabilities of Enterobacter cloacae CAL2 and UW4; Saleh SS et al.; The plant growth-promoting bacteria Enterobacter cloacae CAL2 and UW4 were genetically transformed with a multicopy plasmid containing an rpoS or gacS gene from Pseudomonas fluorescens . The transformed strains were compared with the nontransformed strains for growth, indoleacetic acid (IAA) production, antibiotic production, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, siderophore production, cell morphology, and the ability to promote canola root elongation . All transformed strains had a longer lag phase, were slower in reaching stationary phase, and attained a higher cell density than the nontransformed strains . Transformation resulted in cells that were significantly shorter than the nontransformed cells . The transformed strains also produced significantly more IAA than the nontransformed strains . Introduction of rpoS or gacS from Pseudomonas fluorescens was associated with a reduction in the production of both antibiotics, 2,4-diacetylphloroglucinol and mono-acetylphloroglucinol, produced by Enterobacter cloacae CAL2 . With Enterobacter cloacae CAL2, plasmid-borne rpoS, but not gacS, increased the level of ACC deaminase activity, while introduction of rpoS in Enterobacter cloacae UW4 caused a decrease in ACC deaminase activity . Neither gacS nor rpoS significantly affected the level of siderophores synthesized by either bacterial strain . Overproduction of either GacA or RpoS in Enterobacter cloacae CAL2 resulted in a significant increase in the root lengths of canola seedlings when seeds were treated with the bacteria, and overproduction of RpoS caused an increase in canola shoot as well as root lengths.

Blood Purif, 2001, 19(4), 380 - 7
Blood components influence cytokine induction by bacterial substances; Schindler R et al.; While some studies clearly demonstrated transfer of cytokine-inducing substances (CIS) through dialysis membranes, other authors were unable to reproduce such a transfer . This inconsistency may have been caused by marked differences in experimental design . We performed a systematic evaluation of cytokine induction in whole blood and from separated peripheral blood mononuclear cells (PBMC) using either purified lipopolysaccharide (LPS) or culture supernatants from various bacterial strains . An in vitro hemodialysis circuit with whole blood in the blood compartment was employed; the dialysate was contaminated with sterile filtrates from Pseudomonas aeruginosa cultures . Addition of plasma samples from the blood side to PBMC readily induced interleukin (IL)-1beta and IL-6 after contamination of the dialysate, while the same samples failed to induce cytokine production in whole blood . In experiments using direct incubation, purified P . aeruginosa LPS induced more IL-1beta and IL-6 in whole blood compared to PBMC . In contrast, bacterial filtrates from Escherichia coli, Enterobacter cloacae and especially P . aeruginosa induced significantly less cytokines in whole blood compared to PBMC . Addition of erythrocytes but not granulocytes decreased cytokine induction by bacterial filtrates as well as by LPS, probably by adsorption of these substances . The addition of 30% plasma increased cytokine induction by LPS but decreased cytokine induction by P . aeruginosas filtrates . Our results suggest that cellular and plasmatic components of whole blood interact with bacterial CIS altering their pyrogenic activity . The detection of CIS depends on the test system used; whole blood cultures are not as sensitive for the detection of CIS from bacterial filtrates as PBMC cultures .

J Clin Microbiol, 2001 Oct, 39(10), 3772 - 4
Contamination of the clinical microbiology laboratory with vancomycin-resistant enterococci and multidrug- resistant Enterobacteriaceae: implications for hospital and laboratory workers; Collins SM et al.; We surveyed environmental surfaces in our clinical microbiology laboratory to determine the prevalence of vancomycin-resistant enterococci (VRE) and multidrug-resistant Enterobacteriaceae (MDRE) during a routine working day . From a total of 193 surfaces, VRE were present on 20 (10%) and MDRE were present on 4 (2%) of the surfaces tested . In a subsequent survey after routine cleaning, all of the 24 prior positive surfaces were found to be negative . Thus, those in the laboratory should recognize that many surfaces may be contaminated by resistant organisms during routine processing of patient specimens.

J Clin Microbiol, 2001 Oct, 39(10), 3724 - 6
Increased prevalence of class I integrons in Escherichia coli, Klebsiella species, and Enterobacter species isolates over a 7-year period in a German university hospital; Schmitz FJ et al.; The prevalence of integrons in five enterobacterial species was analyzed in 900 blood culture isolates from 1993, 1996, and 1999 . Remarkably, the prevalence increased from 4.7% in 1993 to 9.7% in 1996 and finally to 17.4% in 1999 (P < 0.01) . Within 7 years the combined percentage of P1 strong promoters and P1 weak plus P2 active promoters with high transcription efficacies has increased from 23.1 to 33.3 and finally 60% (P < 0.05).

Biochem Soc Symp, 2001, (68), 143 - 53
Degradation of explosives by nitrate ester reductases; Williams RE et al.; Explosive-contaminated land poses a hazard both to the environment and to human health . Microbial enzymes, either in their native or heterologous hosts, are a powerful and low-cost tool for eliminating this environmental hazard . As many explosives have only been present in the environment for 10 years, and with similar molecules not known in Nature, the origin of enzymes specialized for the breakdown of explosives is of particular interest . Screening of environmental isolates resulted in the discovery of flavoproteins capable of denitrating the explosives pentaerythritol tetranitrate (PETN) and glycerol trinitrate . These nitrate ester reductases are related in sequence and structure to Old Yellow Enzyme from Saccharomyces carlsbergenisis . All the members of this family have alpha/beta barrel structures and FMN as a prosthetic group, and reduce various electrophilic substrates . The nitrate ester reductases are, however, unusual in that they display activity towards the highly recalcitrant, aromatic explosive 2,4,6-trinitrotoluene, via a reductive pathway resulting in nitrogen liberation . We have embarked on a detailed study of the structure and mechanism of PETN reductase from a strain of Enterobacter cloacae . Work is focused currently on relating structure and function within this growing family of enzymes, with a view to engineering novel enzymes exhibiting useful characteristics.

Antibiot Khimioter, 2001, 46(6), 12 - 20
{Monitoring of uropathogens and their susceptibility to antibiotics}; Savitskaia KI et al.; Samples of urine collected from patients with complicated urology infection and hospitalized to the Moscow Region Research Clinical Institute in 1986, 1991, 1995 and 1999 were analysed . Of 11,444 samples examined, bacteriuria was estimated in 7143 samples . 9786 strains (29 genus) of bacteria were isolated--56.9 per cent as mono culture and 43.1 per cent as associations . Susceptibility to 21 antibiotic was determined by disk diffusion method for 1607 strains; beta-lactamase production was determined in 198 strains, MIC was determined for 41 antibiotics . Gram-negative rods relative amount among pathogens decreased substantially (84.7 per cent in 1986 against 61.6 per cent in 1999), particularly Enterobacteriaceae (74.7 per cent in 1986 against 41.4 per cent in 1999) . Nonfermenting Gram-negative rods (NFGNR) relative amount increased (10.8 per cent against 19.2 per cent), along with Gram-positive cocci (19.8 per cent against 64.2 per cent), particularly coagulasenegative staphylococci (CNS) (10.8 per cent against 35.9 per cent) and enterococci (5 per cent against 16.5 per cent) and candida and fungi (0.5 per cent in 1986 against 15.9 per cent in 1999) . At the period 1986-1999 the main pathogens in urology infection were E . coli, Enterobacter spp., NFGNR (including P . aeruginosa), Staphylococcus, CNS, Enterococcus spp . The problem pathogens for urological department were the following: E . coli, Klebsiella spp., Enterobacter spp., Proteus spp., NFGNR including P . aeruginosa, CNS, Enterococcus spp., candida and fungi . At the period 1991-1997 Gram-negative pathogens susceptibility to amikacin, ofloxacin, ciprofloxacin, imipenem, ceftazidime, cefotaxime was not changed in general, Gram-positive cocci (staphylococci and enterococci) retained the same susceptibility to vancomicin, cefamandol and amoxyclave . Staphylococci were also susceptible to amikacin, imipenem, rifampicin, oxacillin, ciprofloxacin, and ofloxacin . Production of beta-lactamase was registered for 38.7 per cent of CNS, 26.5 per cent of E . coli, 38.5 per cent of K . pneumoniae, 25 per cent of P . mirabilis and 55.6 per cent of P . aeruginosa strains.

Appl Environ Microbiol, 2001 Oct, 67(10), 4760 - 4
Survival of salmonellae on and in tomato plants from the time of inoculation at flowering and early stages of fruit development through fruit ripening; Guo X et al.; The fate of salmonellae applied to tomato plants was investigated . Five Salmonella serotypes were used to inoculate tomato plants before and after fruits set, either by injecting stems with inoculum or brushing flowers with it . Ripe tomato fruits were subjected to microbiological analysis . Peptone wash water, homogenates of stem scar tissues, and homogenates of fruit pulp were serially diluted and plated on bismuth sulfite agar before and after enrichment . Presumptive Salmonella colonies were confirmed by serological tests, PCR assay using HILA2 primers, and enterobacterial repetitive intergenic consensus PCR . Of 30 tomatoes harvested from inoculated plants, 11 (37%) were positive for Salmonella . Of the Salmonella-positive tomatoes, 43 and 40%, respectively, were from plants receiving stem inoculation before and after flower set . Two of eight tomatoes produced from inoculated flowers contained Salmonella . Higher percentages of surface (82%) and stem scar tissue (73%) samples, compared to pulp of Salmonella-positive tomatoes (55%), harbored the pathogen . Of the five serotypes in the inoculum, Montevideo was the most persistent, being isolated from tomatoes 49 days after inoculation, and Poona was the most dominant, being present in 5 of 11 Salmonella-positive tomatoes . Results suggest that Salmonella cells survive in or on tomato fruits from the time of inoculation at flowering through fruit ripening . Tomato stems and flowers are possible sites at which Salmonella may attach and remain viable during fruit development, thus serving as routes or reservoirs for contaminating ripened fruit.

Anal Chem, 2001 Sep 1, 73(17), 4241 - 8
Electrochemical biosensor array for the identification of microorganisms based on lectin-lipopolysaccharide recognition; Ertl P et al.; Rapid identification of bacterial strains remains a well-known problem in applied medicine and, for viable pathogens, is an important diagnostic goal . We have investigated an electrochemical biosensor array, in which transduction is based on respiratory cycle activity measurements, where the microorganism's native respiratory chain is interrupted with non-native external oxidants . The selective biochemical recognition agents employed in this study are lectins that, once immobilized, recognize and bind to cell surface lipopolysaccharides . Porous membranes with different surface properties were examined as potential immobilization supports for these lectins . Optimizations performed using concanavalin A and E . coli JM105 show that immobilization methods involving pre-activated membranes significantly reduce the time required to create a functional lectin layer on the membrane surface . Overall, we found general agreement between agglutination test results and the electrochemical assessment of lectin-cell binding . Chronocoulometric measurements were made for cells captured on lectin-modified Immunodyne ABC membranes physically affixed to Pt working electrodes . This lectin-based sensor array was exposed to viable cells of gram-negative and gram-positive bacteria as well as yeast, and chronocoulometric measurements were used to generate a pattern of responses for each organism toward each lectin . Principal component analysis was used to classify the chronocoulometric results for the different microbial strains . With this new method, six microbial species (Baccilus cereus, Staphylococcus aureus, Proteus vulgaris, Escherichia coli, Enterobacter aerogenes, Saccharomyces cerevisiae) were readily distinguished.

Zh Mikrobiol Epidemiol Immunobiol, 2001 Jul-Aug, (4), 86 - 9
{Characteristics of changes in microbiocenosis in patients with chronic nonspecific urethritis}; Bukharin OV et al.; The species composition and the complex of biological characteristics of microflora in the front section of urethra in healthy males and in patients with chronic nonspecific urethritis . The study revealed that in patients with chronic nonspecific nongonococcal urethritis changes in the microbiocenosis of the urethra were observed . These changes were manifested by a decrease in the number of species, the appearance of Grain-negative enterobacterial flora and an increase in the persistence potential of symbiotic bacteria . These disturbances are regarded as the manifestation of urogenital dysbiosis.

Zh Mikrobiol Epidemiol Immunobiol, 2001 Jul-Aug, (4), 107 - 11
{Characteristics of enterobacteria isolated from patients with urogenital pathology}; Gritsenko VA et al.; Species composition and a number of persistence characteristics enterobacteria isolated from urine of 42 pregnant and 22 nonpregnant women with pyelonephritis (relapse, remission), from prostatic fluid of 225 males and secretions of cervical canal of 124 women with urogenital pathology (prostatitis, salpingo-oophoritis) were studied . The study revealed that enterobacteria, including Escherichia coli, prevailed in the structure of uromicroflora (66.7-83.3%) and constituted a relatively small proportion among "genital" isolates of microorganisms (19.9-22.2%) . Male and female sterility and the presence of enterobacteria in the reproductive tract of patients were found to be directly correlated . Clinical isolates of enterobacteria were shown to possess pronounced seroresistance and the complex of persistence characteristics, including antilysozyme, anti-intercidal and anticomplementary activity.

Clin Infect Dis, 2001 Nov 1, 33(9), 1513 - 9 Epub 2001 Sep 24.
The microbiology of postoperative peritonitis; Roehrborn A et al.; Postoperative peritonitis carries a higher risk of complications and mortality than does community-acquired disease . Little, however, is known about the specific microbiology of this condition . To gain insight into this problem, the microbiological findings of 67 patients with postoperative peritonitis were compared with those of 68 patients with community-acquired peritonitis . In a comparison of postoperative peritonitis with community-acquired disease, the number of isolates of enterococci (23 versus 6) and Enterobacter species (13 versus 4) were increased and the number of isolates of Escherichia coli (21 versus 42) were reduced . Antibiotic therapy before reintervention increased the number of resistant organisms at relaparotomy (33% versus 8%) . The in vitro efficacy of the primary antibiotic or combination of drugs did not affect mortality rates (40% versus 38% after effective and ineffective treatment, respectively) . Thus, the microbiology of postoperative peritonitis differs significantly from that of community-acquired disease, and specific antibiotic therapy is required, despite the doubtful impact on survival.

Biofactors, 2001, 14(1-4), 241 - 54
Bioremediation of selenium-contaminated sediments and water; Frankenberger WT Jr et al.; Selenium (Se) is a contaminant of agricultural irrigation-drainage water in the western United States, and the cause of wildlife deaths and grotesque deformities . Some approaches in reducing the toxic Se concentrations from contaminated sediments and water have been proposed, but most of these tend to be costly or ineffective . Bioremediation through microbial transformations of toxic Se species into nontoxic forms is being considered as an effective remedial alternative . The microbial reduction of toxic oxyanions of Se (SeO(4)(2-) and SeO(3)(2-)) into insoluble Se(0) or methylation of these species to dimethylselenide (DMSe) has been accepted as a potential bioremediation strategy for cleanup of Se-contaminated water and sediments . By conducting a series of laboratory, bench-scale and field studies, we have thoroughly investigated the remedial potential of these approaches . It was observed that microorganisms, particularly Enterobacter cloacea, are very active in reduction of Se oxyanions present in irrigation drainage water, into insoluble Se(0) and, by monitoring various environmental conditions and addition of organic amendments, the process could be stimulated manifold . Similarly, the process of biomethylation of Se in soil sediments and water was found active and highly dependent on specific carbon amendments (pectin and proteins), pH, temperature, moisture, aeration and activators (cofactors) . Moreover, Se biomethylation was protein/peptide-limited rather than nitrogen-, amino acid- or carbon-limited . Crude casein and its components were equally stimulatory producing a >50-fold enhancement in DMSe yield . Methionine and methyl cobalamin stimulated DMSe production by Alternaria alternata, indicating that the coenzyme may mediate the transfer of a methyl group to the Se atom . An acute toxicity test involving inhalation of DMSe by rats revealed that DMSe is nontoxic . Experiments were scaled up from laboratory studies to field plots to verify the feasibility of this bioremediation approach . Based upon the promising results of these studies, a biotechnology prototype was developed which could be applicable for cleanup of polluted sediments and water throughout the western United States.

J Photochem Photobiol B, 2001 Sep 15, 62(3), 158 - 65
Sublethal effects of ultraviolet A radiation on Enterobacter cloacae; Oppezzo OJ et al.; We report the sublethal effects of ultraviolet A (UVA) on Enterobacter cloacae in comparison with those produced in Escherichia coli . UVA-induced sublethal effects were investigated in either bacterial membrane and at tRNA level . Limited dependence on oxygen concentration for photoinduced inhibition of biochemical membrane functions and low levels of oxidative damage during the irradiation period were found in En . cloacae . On the other hand, ultraviolet spectroscopy and reversed-phase HPLC analysis of hydrolysed tRNA showed that radio induced damage to tRNA is similar in En . cloacae and E . coli . Nevertheless, growth delay induced by UVA in En . cloacae was shorter than that found in E . coli submitted to the same experimental conditions . A limited post-irradiation ppGpp accumulation and the absence of any influence of the membrane damage on the growth delay extent seem to be responsible for the shortness of this effect in En . cloacae . Most of the differences between En . cloacae and E . coli could be attributed to an increased ability of En . cloacae to overcome oxidative stress during UVA exposure.

Ross Gastroenterol Zh, 2001, (1), 54 - 69
{Comparative study of chromatography-mass spectrography of microorganism's chemical markers in blood and intestinal mucosa bioptats}; Osipov GA et al.; Fatty acids, that are microorganism's markers in blood and jejunum's, ileum's, and large intestine's bioptats of the patients with irritable bowel syndrome were investigated with gas chromatography . Markers of Cl . perfringens, Cl . difficile, Enterococcus, Streptomyces, Enterobacterial, Klebsiella, E . coli, Peptostreptococcus, Candida Albicans, genus of Streptococcus, of Staphylococcus, of Fusobacterium sp and others microorganisms were revealed . Settling of intestinal mucosa was the same in jejunum, ileum and large intestine (0.5-1.3) x 10(10) cells/gr . and was approximately the same as microorganism's concentration in feces (1.8 x 10(11) cells/gr) . Correlation of blood and bioptats markers was demonstrated in the most patients . The possibility to use specific fatty blood acids as microorganisms markers in preliminary diagnosis of mucosa microflora changes is discussed.

J Clin Virol, 2001 Oct, 22(3), 217 - 27
Lipid rafts and HIV-1: from viral entry to assembly of progeny virions; Campbell SM et al.; BACKGROUND: Lipid rafts are currently an intensely investigated topic of cell biology . In addition to a demonstrated role in signal transduction of the host cell, lipid rafts serve as entry and exit sites for microbial pathogens and toxins, such as FimH-expressing enterobacteria, influenza virus, measles virus and cholera toxin . Furthermore, caveolae, a specialised form of lipid raft, are required for the conversion of the non-pathogenic prion protein to the pathogenic scrapie isoform . OBJECTIVES: A number of reports have shown, directly or indirectly, that lipid rafts are important at various stages of the human immunodeficiency virus type-1 (HIV-1) replication cycle . The purpose of this paper is to provide a brief overview of the role of membrane-associated lipid rafts in cell biology, and to evaluate how HIV-1 has hijacked this cellular component to support HIV-1 replication . Special sections are devoted to discussing the role of lipid rafts in (1) the entry of HIV-1, (2) signal transduction regulation in HIV-1-infected cells, (3) the trafficking of HIV-1 proteins via lipid rafts during HIV-1 assembly; and a further section discusses the role of cholesterol in mature HIV-1 . SUMMARY: Like a number of other pathogens, HIV-1 has evolved to rely on the host cell lipid rafts to support its propagation during multiple stages of the HIV-1 replication cycle . This review has highlighted the importance of lipid rafts in HIV-1 replication.

Semin Respir Infect, 2001 Sep, 16(3), 215 - 24
Future of the quinolones; Ball P; New fluoroquinolones and fluoronaphthyridones continue to provide the mainstay of antibiotic development, despite recent events associated with unexpected or uncharacteristically severe adverse drug reactions . These have included hepatotoxicity caused by trovafloxacin (suspended), cardiotoxicity associated with grepafloxacin, and phototoxicity caused by clinafloxacin (both withdrawn) . Prolongation of the QT interval appears to be an emergent class effect, the implications of which are not yet fully understood . However, the second-generation agents ciprofloxacin and, latterly, levofloxacin have excellent safety profiles and provide standard optimal choices for therapy of a wide range of gram-negative pathogens . They are also useful for many respiratory infections, though the use of ciprofloxacin in pneumococcal pneumonia has been questioned and continued use of levofloxacin may act as a selection pressure for emergence of quinolone-resistant Streptococcus pneumoniae . Active conservation measures may be required to protect the class from this problem because alternatives, should high-level penicillin-resistance continue to spread, are few . The new 8-methoxy quinolones (moxifloxacin and gatifloxacin) are more highly potent against both penicillin-susceptible and multidrug-resistant S . pneumoniae, while retaining activity against enterobacteria . Clinical Phase III development has shown them to produce very satisfactory clinical and bacteriologic responses in respiratory infections and to be remarkably free of clinically significant adverse effects . Postmarketing surveillance of moxifloxacin in Germany has revealed no additional concerns . These agents are now licensed in many countries, including the United States, and add a further, broad-based respiratory dimension to the future of the class .

Eur J Clin Microbiol Infect Dis, 2001 Jul, 20(7), 486 - 9
Ciprofloxacin- and methicillin-resistant staphylococcus aureus susceptible to moxifloxacin, levofloxacin, teicoplanin, vancomycin and linezolid; Presterl E et al.; In order to determine the comparative efficacy of vancomycin, teicoplanin, levofloxacin, moxifloxacin, and linezolid against methicillin- and ciprofloxacin-resistant Staphylococcus aureus, each agent was tested against 65 genetically different strains using the microbroth dilution method . All of the isolates were typed using the enterobacterial repetitive intergenic consensus polymerase chain reaction to exclude multiple isolates of epidemic clones . Susceptibility testing revealed that all of the isolates were susceptible to vancomycin and teicoplanin . Linezolid exhibited minimum inhibitory concentration (MIC) levels ranging from 1 to 4 mg/l (MIC90, 4 mg/l) . The MICs of moxifloxacin and levofloxacin ranged from 0.01 to 8 mg/l (MIC90, 8 mg/l) and 0.25 to 32 mg/l (MIC90 . 16 mg/l), respectively . Thus, linezolid is active against methicillin- and ciprofloxacin-resistant Staphylococcus aureus, whereas moxifloxacin may need to be administered at a dose higher than recommended in order to successfully treat serious infections.

AJNR Am J Neuroradiol, 2001 Sep, 22(8), 1510 - 6
CT and MR imaging features of pyogenic ventriculitis; Fukui MB et al.; BACKGROUND AND PURPOSE: Pyogenic ventriculitis is an uncommon manifestation of severe intracranial infection that might be clinically obscure . We hypothesized that determining characteristic imaging features of pyogenic ventriculitis in patients with appropriate risk factors might improve recognition of this severe infection . METHODS: Review of the medical records from 1990 to 2000 revealed 17 cases (12 men, five women) that satisfied inclusion criteria of abscess (n = 3) and/or positive cultures or increased white cells and protein in ventricular (n = 12) or cisternal (n = 1) cerebrospinal fluid . In one case, the diagnosis of ventriculitis was based on the combination of bacterial growth in lumbar cerebrospinal fluid and follow-up imaging . Staphylococcus species and Enterobacter species were the most common organisms . Two neuroradiologists independently evaluated imaging studies for hydrocephalus, ventricular debris, periventricular attenuation or signal abnormality, ependymal enhancement, and signs of meningitis or abscess . Sixteen studies in 11 patients were performed after the intravenous administration of contrast material . RESULTS: Ventricular debris was detected in 16 (94%) of 17 cases and was irregular in 13 (81%) of 16 cases . Hydrocephalus was present in 13 (76%) of 17 cases . Periventricular hyperintense signal was present in most (seven {78%} of nine) cases with MR imaging and was most conspicuous on fluid-attenuated inversion recovery sequences . Ependymal enhancement was detected in seven (64%) of 11 cases in which contrast material was administered . Signs of meningitis (eg, pial or duraarachnoid signal abnormality or enhancement) were present in 13 (76%) of 17 cases . Three cases had imaging signs of abscess . CONCLUSION: Ventricular debris was the most frequent sign of ventriculitis in this series . An irregular level was characteristic of debris in ventriculitis . Hydrocephalus and ependymal enhancement were less frequent signs . Detection of ventricular debris might facilitate diagnosis of pyogenic ventriculitis, a potentially fatal infection, and thus permit appropriate therapy.

Antimicrob Agents Chemother, 2001 Oct, 45(10), 2965 - 8
Biochemical-genetic characterization of the chromosomally encoded extended-spectrum class A beta-lactamase from Rahnella aquatilis; Bellais S et al.; From whole-cell DNA of a clinical isolate of the enterobacterial species Rahnella aquatilis, a beta-lactamase gene was cloned that encoded a chromosomally encoded Ambler class A enzyme, RAHN-1 . RAHN-1, with a pI of 7.2, shares 76, 73, and 71% amino acid identity with the extended-spectrum beta-lactamase of chromosomal origin from Serratia fonticola and with the plasmid-mediated beta-lactamases CTX-M-2 and CTX-M-1, respectively . The hydrolysis spectrum of the clavulanic acid-inhibited RAHN-1 was expanded to cephalosporins such as cefuroxime, cefotaxime, and ceftriaxone, but not to ceftazidime . Its expression was not inducible.

Antimicrob Agents Chemother, 2001 Oct, 45(10), 2961 - 4
Novel gene cassettes and integrons; Peters ED et al.; An increase in multiresistant Enterobacteriaceae was observed at one of the departments of the University Medical Center Utrecht . Nine different integrons and 17 gene cassettes were found, including the new gene cassette aadA8 . This cassette was highly related to aadA3 and aadA2 . In addition, an unknown promoter sequence was found for two integrons.

Antimicrob Agents Chemother, 2001 Oct, 45(10), 2908 - 15
AmpD is required for regulation of expression of NmcA, a carbapenem-hydrolyzing beta-lactamase of Enterobacter cloacae; Naas T et al.; To further elucidate the induction process of the carbapenem-hydrolyzing beta-lactamase of Ambler class A, NmcA, ampD genes of the wild-type (WT) strain and of ceftazidime-resistant mutants of Enterobacter cloacae NOR-1 were cloned and tested in transcomplementation experiments . Ceftazidime-resistant E . cloacae NOR-1 mutants exhibited derepressed expression of the AmpC-type cephalosporinase and of the carbapenem-hydrolyzing beta-lactamase NmcA . The ampD genes of Escherichia coli and E . cloacae WT NOR-1 transcomplemented the ceftazidime-resistant E . cloacae NOR-1 mutants to the WT level of beta-lactamase expression, while the mutated ampD alleles of E . cloacae NOR-1 failed to do so . The deduced E . cloacae NOR-1 WT AmpD protein exhibited 95 and 91% amino acid identity with the E . cloacae O29 and E . cloacae 14 WT AmpD proteins, respectively . Of the 12 ceftazidime-resistant E . cloacae NOR-1 strains, 3 had AmpD proteins with amino acid changes, while the others had truncated AmpD proteins . Most of these mutations were located outside the conserved regions that link the AmpD proteins to the cell wall hydrolases . AmpD from E . cloacae NOR-1 is involved in the regulation of expression of both beta-lactamases (NmcA and AmpC), suggesting that structurally unrelated genes may be under the control of an identical genetic system.

Antimicrob Agents Chemother, 2001 Oct, 45(10), 2885 - 90
Molecular analysis of tetracycline resistance in Pasteurella aerogenes; Kehrenberg C et al.; Tetracycline-resistant Pasteurella aerogenes isolates obtained from the intestinal tract of swine were investigated for their tet genes by PCR analysis and hybridization experiments . In contrast to Pasteurella isolates from the respiratory tract, tet(H) genes were detected in the chromosomal DNA of only 2 of the 24 isolates, one of which also carried two copies of a tet(B) gene . All other P . aerogenes isolates carried tet(B) genes, which are the predominant tet genes among Enterobacteriaceae . A single isolate harbored a tet(B) gene as part of a truncated Tn10 element on the 4.8-kb plasmid pPAT2 . Comparative analysis of the pPAT2 sequence suggested that the Tn10 relic on plasmid pPAT2 is the result of several illegitimate recombination events . The remaining 21 P . aerogenes isolates carried one or two copies of the tet(B) gene in their chromosomal DNA . In the majority of the cases, these tet(B) genes were associated with copies of Tn10 as confirmed by their SfuI and BamHI hybridization patterns . No correlation between the number of tet gene copies and the MICs of tetracycline, doxycyline and minocycline was observed.

Recenti Prog Med, 2001 Sep, 92(9), 537 - 9
{Scombroid syndrome with severe and prolonged cardiovascular involvement}; Tursi A et al.; Scombroid poisoning is a form of ichthyosarcotoxism caused by eating spoiled fish, mainly of the scombroid family . Inappropriate storage of these fish can lead to the decarboxylation of histidine in the flesh to histamine by enterobacteria . The symptoms of histamine poisoning mimic those of an IgE-mediated food allergy, as well as flushing, headache, diarrhea and palpitations . However, in some cases, the scombroid poisoning can be characterized by very serious symptoms, as well as cardiovascular compromission . We describe two cases of scombroid poisoning with severe hypotension requiring continuous intravenous dopamine with resolution of symptoms only several hours later.

Epidemiol Mikrobiol Imunol, 2001 Aug, 50(3), 121 - 30
{Occurrence and mechanisms of resistance to beta-lactam antibiotics in clinically important species of Enterobacter}; Michalkova-Papajova D et al.; Extended-spectrum beta-lactam antibiotics have found great medical importance, but their wide use in clinical practice leads to increasing resistance to them . The more frequent occurrence of infections caused by Bush group 1 beta-lactamase producing organisms, including species of the genus Enterobacter, is a serious problem in this field . Resistance to beta-lactams in this important nosocomial pathogens can be due to 1) reduction in outer membrane permeability to antibiotics caused by alterations in outer membrane lipopolysacharides or proteins (porins); 2) production of beta-lactamases, which inactivate beta-lactams and can also lead to resistance by non-hydrolytic mechanism called trapping . Production of plasmid-mediated extended-spectrum beta-lactamases, but especially chromosomally-mediated inducible cephalosporinase AmpC, which can be synthesized constitutively in large amounts as consequence of spontaneous chromosomal mutations, are of great clinical importance . Fourth-generation cephalosporins and carbapenems are the most effective in the treatment of infections caused by species belonging to the genus Enterobacter, but combination of high level beta-lactamase production and decreased outer membrane permeability, which is not rare in Enterobacter spp., leads to resistance even to these drugs.

Zh Mikrobiol Epidemiol Immunobiol, 2001 Mar-Apr, (2), 89 - 91
{Effect of organic composition of humic acids on Enterobacteria multiplication}; Buzoleva LS et al.; Enterobacteria have been found to be capable of active multiplication in humic acids isolated from bentonite clays containing carbohydrates, lipids and proteins . Humic acids fractions have been found to be heterogeneous by their molecular weight and organic composition; consequently, they have been found to produce different influence in the multiplication of bacteria.

Zh Mikrobiol Epidemiol Immunobiol, 2001 Mar-Apr, (2), 81 - 2
{Diagnostic and epidemiological significance of F-donor activity of Enterobacteria strains}; Lipovskaia VV et al.; The study of the circulating strains of enteropathogenic Escherichia coli (EPEC), shigellae and salmonellae for the presence of F-factor (the conjunction factor) was carried out . The study revealed that 85% of Shigella flexneri strains 2a had conjugative (F)-factor . The proportion of such strains was 63% among EPEC of different serovars and 15% among Salmonella enteritidis . As 63% EPEC strains had hemolytic activity and were found to carry F-conjugative plasmid it should be taken into consideration in the identification of microorganisms . The presence of conjugation plasmids is an important epidemiological marker.

Zh Mikrobiol Epidemiol Immunobiol, 2001 Mar-Apr, (2), 10 - 2
{Viability of facultative anaerobic bacteria in commercial transport systems}; Gruber IM et al.; The possibilities of the transport systems manufactured by Copan (Italy) and Deltalab (Spain) were studied on 15 microbial strains: representatives of the family Enterobacteriaceae (enterobacterial swabs with Cary-Blair medium) and the genus Streptococcus, as well as the species Neisseria meningitidis, Haemophilus influenzae (universal swabs with charcoal-enriched Amies medium) . Microorganisms were shown to retain their viability (in colony-forming units, %) for 48 hours in the systems of both firms . H . influenzae exhibited greater viability in the system manufactured by Copan than in that manufactured by Deltalab (respectively, 62% and 28% in 24 hours, 19% and 6% in 48 hours).

J Mol Biol, 2001 Sep 7, 312(1), 7 - 16
Transfer of the Salmonella type III effector sopE between unrelated phage families; Mirold S et al.; Salmonella spp . are pathogenic enterobacteria that employ type III secretion systems to translocate effector proteins and modulate responses of host cells . The repertoire of translocated effector proteins is thought to define host specificity and epidemic virulence, and varies even between closely related Salmonella strains . Therefore, horizontal transfer of effector protein genes between Salmonella strains plays a key role in shaping the Salmonella-host interaction . Several effector protein genes are located in temperate phages . The P2-like phage SopE Phi encodes SopE and the lambda-like GIFSY phages encode several effector proteins of the YopM/IpaH-family . Lysogenic conversion with these phages is responsible for much of the diversity of the effector protein repertoires observed among Salmonella spp . However, free exchange of effector proteins by lysogenic conversion can be restricted by superinfection immunity . To identify genetic mechanisms that may further enhance horizontal transfer of effector genes, we have analyzed sopE loci from Salmonella spp . that do not harbor P2-like sequences of SopE Phi . In two novel sopE loci that were identified, the 723 nt sopE gene is located in a conserved 1.2 kb cassette present also in SopE Phi . Most strikingly, in Salmonella enterica subspecies I serovars Gallinarum, Enteritidis, Hadar and Dublin, the sopE-cassette is located in a cryptic lambda-like prophage with similarity to the GIFSY phages . This provides the first evidence for transfer of virulence genes between different phage families . We show that such a mechanism can circumvent restrictions to phage-mediated gene transfer and thereby enhances reassortment of the effector protein repertoires in Salmonella spp .

J Bacteriol, 2001 Oct, 183(19), 5684 - 97
Complete nucleotide sequence and organization of the atrazine catabolic plasmid pADP-1 from Pseudomonas sp . strain ADP; Martinez B et al.; The complete 108,845-nucleotide sequence of catabolic plasmid pADP-1 from Pseudomonas sp . strain ADP was determined . Plasmid pADP-1 was previously shown to encode AtzA, AtzB, and AtzC, which catalyze the sequential hydrolytic removal of s-triazine ring substituents from the herbicide atrazine to yield cyanuric acid . Computational analyses indicated that pADP-1 encodes 104 putative open reading frames (ORFs), which are predicted to function in catabolism, transposition, and plasmid maintenance, transfer, and replication . Regions encoding transfer and replication functions of pADP-1 had 80 to 100% amino acid sequence identity to pR751, an IncPbeta plasmid previously isolated from Enterobacter aerogenes . pADP-1 was shown to contain a functional mercury resistance operon with 99% identity to Tn5053 . Complete copies of transposases with 99% amino acid sequence identity to TnpA from IS1071 and TnpA from Pseudomonas pseudoalcaligenes were identified and flank each of the atzA, atzB, and atzC genes, forming structures resembling nested catabolic transposons . Functional analyses identified three new catabolic genes, atzD, atzE, and atzF, which participate in atrazine catabolism . Crude extracts from Escherichia coli expressing AtzD hydrolyzed cyanuric acid to biuret . AtzD showed 58% amino acid sequence identity to TrzD, a cyanuric acid amidohydrolase, from Pseudomonas sp . strain NRRLB-12227 . Two other genes encoding the further catabolism of cyanuric acid, atzE and atzF, reside in a contiguous cluster adjacent to a potential LysR-type transcriptional regulator . E . coli strains bearing atzE and atzF were shown to encode a biuret hydrolase and allophanate hydrolase, respectively . atzDEF are cotranscribed . AtzE and AtzF are members of a common amidase protein family . These data reveal the complete structure of a catabolic plasmid and show that the atrazine catabolic genes are dispersed on three disparate regions of the plasmid . These results begin to provide insight into how plasmids are structured, and thus evolve, to encode the catabolism of compounds recently added to the biosphere.

Appl Environ Microbiol, 1992 Jun, 58(6), 2089 - 92
Evaluation of the Biolog automated microbial identification system; Klingler JM et al.; Biolog's identification system was used to identify 39 American Type Culture Collection reference taxa and 45 gram-negative isolates from water samples . Of the reference strains, 98% were identified to genus level and 76% to species level within 4 to 24 h . Identification of some authentic strains of Enterobacter, Klebsiella, and Serratia was unreliable . A total of 93% of the water isolates were identified.

Med Sci Monit, 2001 Sep-Oct, 7(5), 869 - 77
Intestinal protection by lafutidine, a histamine H(2)-receptor antagonist, against indomethacin-induced damage in rats--role of endogenous nitric oxide; Tanaka A et al.; BACKGROUND: We previously reported that lafutidine ((I)-2-(furfurylsulfinyl)-N-{4-{4-(piperidinomethyl)-2-pyridyl}oxy-(Z)-2-butenyl} acetamide), a novel histamine H(2)-receptor antagonist, protects the small intestine against indomethacin-induced damage, mediated by capsaicin-sensitive afferent neurons (CSN) . MATERIAL AND METHODS: In the present study, we investigated whether or not the protective action of lafutidine against indomethacin-induced intestinal damage is mediated by endogenous nitric oxide (NO) . Male SD rats were given indomethacin (10 mg/kg, s.c), killed 24 hr later, and the small intestinal mucosa was examined . Lafutidine (10 mg/kg) and capsaicin (10 mg/kg) was given p.o . twice 0.5 hr before and 9 hr after indomethacin . The NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME: 10 mg/kg) or the selective iNOS inhibitor aminoguanidine (10 mg/kg) was given s.c . 1 hr before lafutidine, while L-arginine (200 mg/kg) was given i.p . 10 min before L-NAME . RESULTS: Indomethacin produced severe lesions in the small intestine, accompanied by increases in enterobacterial translocation in the mucosa . Both lafutidine and capsaicin significantly reduced the severity of these lesions, together with suppression of bacterial translocation . The protective action of lafutidine as well as capsaicin was almost totally abolished by L-NAME but not aminoguanidine, in a L-arginine-sensitive manner . Both lafutidine and capsaicin significantly increased intestinal mucus secretion, and these effects were also attenuated by prior administration of L-NAME . The exogenous NO donor NOR-3 prevented indomethacin-induced intestinal lesions at the dose that stimulated the mucus secretion and inhibited the bacterial translocation . CONCLUSIONS: These results suggest that lafutidine protects the small intestine against indomethacin-induced damage, the action being dependent on CSN and mediated by endogenous NO produced by cNOS . The protective action of lafutidine may be attributable to suppression of the bacterial translocation following indomethacin, probably due to stimulation of intestinal mucus secretion.

Am J Surg, 2001 Jul, 182(1), 52 - 7
A new biliodigestive anastomosis technique to prevent reflux and stasis; Klaus A et al.; BACKGROUND: The Roux-en-Y procedure for biliodigestive drainage is most widely accepted, but 10% to 15% of patients postoperatively suffer from a blind-loop syndrome or cholangitis due to motility disorders . A new biliodigestive technique is evaluated in a rat model to prevent these complications . METHODS: This experimental study in Wistar rats compares the Roux-en-Y technique with a new biliodigestive anastomosis creating a jejunal loop with luminal occlusion . Clinical parameters, small bowel motility, bacteriologic growth, and liver histopathology were evaluated in native and postoperative animals within a study period of 180 days . RESULTS: Both operative procedures were well tolerated . After 6 months intense fibrosis of the liver and high-grade purulent cholangitis were observed in animals in the Roux-en-Y group . In these animals enterobacter and enterococci overgrowth was found . Myoelectric small bowel recordings revealed significant impairment of slow-wave frequency, aboral velocity, and action potentials (percentage of phase III) in Roux-en-Y animals . CONCLUSIONS: Motility disorders after conventional Roux-en-Y biliodigestive anastomosis are pivotal for histomorphological damage and infectious findings and can be prevented by using the new technique to create a jejunal loop with luminal occlusion.

Clin Microbiol Infect, 2001 Jul, 7(7), 391 - 3
Recurrent bacteremia by Chryseobacterium indologenes in an oncology patient with a totally implanted intravascular device; Nulens E et al.; Chryseobacterium indologenes was isolated from the blood cultures of an oncological patient with a totally implantable device . Because a catheter-related infection was suspected, the Port-A-Cath was removed after a 10-day course of piperacillin-tazobactam . Differences in susceptibility may exist if either the criteria for either Pseudomonas or Enterobacteriaceae are used.

Clin Microbiol Infect, 2001 Jul, 7(7), 352 - 7
Evaluation of the OSIRIS video reader system for disk diffusion susceptibility test reading; Sanchez MA et al.; OBJECTIVE: The objective of this study was to compare the performance of the OSIRIS video-assisted reading system for disk diffusion susceptibility testing with conventional manual reading . METHODS: Prospectively collected clinical isolates (n = 119) and isolates with well-characterised resistant mechanisms, including extended-spectrum (ESBL) or inhibitor-resistant TEM (IRT) beta-lactamases producing Enterobacteriaceae (80), methicillin-resistant Staphylococcus aureus (MRSA) (16) and vancomycin-resistant enterococci (14) were studied using the National Committee for Clinical Laboratory Standards disk-diffusion technique . The OSIRIS reading (inhibition zone in mm) was compared with manual reading (reference value) . RESULTS: Essential agreement (< or =3 mm discrepancy with manual reading) was 91.6% in routine isolates and 94.8% in those with well-characterised resistant mechanisms, respectively . Overall agreement for susceptibility testing interpretation was slightly higher in the former (95.5%) than in the latter (93.2%) group . The presence of ESBL enzymes enhanced variations of measurements due to synergy among amoxicillin-clavulanate and cephalosporins, as a consequence of closer disk placement . The poor growth characteristic of enterococci affected the video reading; on the other hand, there was a high performance with MRSA isolates . Combining all interpretative results, 4.1% minor, 1.0% major and 2.8% very major errors were observed . CONCLUSION: The OSIRIS system is a useful tool for the reading and interpretation of inhibition zone sizes in disk diffusion susceptibility testing.

Clin Infect Dis, 2001 Oct 1, 33(7), E69 - 74 Epub 2001 Sep 05.
Infections caused by Kluyvera species in humans; Sarria JC et al.; Kluyvera is a relatively newly described genus in the family Enterobacteriaceae that infrequently causes infections in humans . The organism has been isolated from various clinical specimens, but its significance has not been clearly established . In fact, it has been regarded alternatively as saprophytic, opportunistic, or pathogenic . Since the redefinition of this genus in 1981, case reports of diverse clinical infections occurring under various host conditions have been published . Here we present a critical review of all Kluyvera infections reported in the literature, along with our experience involving 5 additional cases . Most patients received prompt antimicrobial treatment on the basis of susceptibility testing, and overall the clinical outcomes were good . Antimicrobial agents active against most Kluyvera strains include third-generation cephalosporins, fluoroquinolones, and aminoglycosides . In contrast, the resistance to ampicillin, extended-spectrum penicillins, and first- and second-generation cephalosporins is significant . Kluyvera is a potentially virulent pathogen that deserves aggressive treatment designed with an awareness of the organism's antimicrobial resistance patterns.

Acta Crystallogr D Biol Crystallogr, 2001 Sep, 57(Pt 9), 1310 - 2 Epub 2001 Aug 23.
Overexpression, purification, crystallization and data collection on the Bordetella pertussis wlbD gene product, a putative UDP-GlcNAc 2'-epimerase; Sri Kannathasan V et al.; The Boredetella pertussis wlbD gene product is a putative uridine-5-diphosphate N-acetylglucosamine (UDP-GlcNAc) 2'-epimerase involved in Band A lipopolysaccharide biosynthesis . The wlbD gene is homologous to Escherichia coli rffE (32% identical), an established UDP-GlcNAc 2'-epimerase that is involved in enterobacterial common antigen (ECA) formation . The structure of the rffE protein reveals an unexpected role for a bound sodium ion in orientating a substrate-binding alpha-helix in the enzyme active site . Whilst key active-site residues in rffE are present in the wlbD sequence, the sodium-binding residues outside the active site are absent . This raises questions about the modulation of enzyme activity in these two enzymes . The wlbD gene from B . pertussis has been cloned and overexpressed in E . coli and the resulting protein has been purified to homogeneity . In the current study, crystals of the mutant Gln339Arg wlbD enzyme have been obtained by sitting-drop vapour diffusion . Uncomplexed Gln339Arg and UDP-GlcNAc complex data sets have been collected in-house on a rotating-anode generator to 2.1 A . Combined, the data sets identify the space group as P2(1)2(1)2(1), with unit-cell parameters a = 78, b = 91, c = 125 A, alpha = beta = gamma = 90 degrees . The asymmetric unit contains two monomers and 53% solvent.

Appl Environ Microbiol, 2001 Sep, 67(9), 4335 - 7
Lytic and lysogenic infection of diverse Escherichia coli and Shigella strains with a verocytotoxigenic bacteriophage; James CE et al.; A verocytotoxigenic bacteriophage isolated from a strain of enterohemorrhagic Escherichia coli O157, into which a kanamycin resistance gene (aph3) had been inserted to inactivate the verocytotoxin gene (vt2), was used to infect Enterobacteriaceae strains . A number of Shigella and E . coli strains were susceptible to lysogenic infection, and a smooth E . coli isolate (O107) was also susceptible to lytic infection . The lysogenized strains included different smooth E . coli serotypes of both human and animal origin, indicating that this bacteriophage has a substantial capacity to disseminate verocytotoxin genes . A novel indirect plaque assay utilizing an E . coli recA441 mutant in which phage-infected cells can enter only the lytic cycle, enabling detection of all infective phage, was developed.

Appl Environ Microbiol, 2001 Sep, 67(9), 3852 - 9
Control of bacterial motility by environmental factors in polarly flagellated and peritrichous bacteria isolated from Lake Baikal; Soutourina OA et al.; Despite numerous studies on bacterial motility, little is known about the regulation of this process by environmental factors in natural isolates . In this study we investigated the control of bacterial motility in response to environmental parameters in two strains isolated from the natural habitat of Lake Baikal . Morphological characterization, carbon source utilization, fermentation analysis, and sequence comparison of 16S rRNA genes showed that these strains belong to two distinct genera, i.e., Enterobacter and Pseudomonas; they were named strains 22 and Y1000, respectively . Both strains swarmed at 25 degrees C and remained motile at low temperatures (4 degrees C), especially the Pseudomonas strain, which further supports the psychrotrophic characteristics of this strain . In contrast, a strong inhibition of motility was observed at above 30 degrees C and with a high NaCl concentration . The existence of flagellar regulatory proteins FlhDC and FleQ was demonstrated in Enterobacter strain 22 and Pseudomonas strain Y1000, respectively, and environmental conditions reduced the expression of the structural genes potentially located at the first level in the flagellar cascade in both organisms . Finally, as in Enterobacter strain 22, a strong reduction in the transcription of the master regulatory gene fleQ was observed in Pseudomonas strain Y1000 in the presence of novobiocin, a DNA gyrase inhibitor, suggesting a link between DNA supercoiling and motility control by environmental factors . Thus, striking similarities observed in the two organisms suggest that these processes have evolved toward a similar regulatory mechanism in polarly flagellated and laterally flagellated (peritrichous) bacteria.

FEBS Lett, 2001 Aug 24, 504(1-2), 69 - 72
The Pla surface protease/adhesin of Yersinia pestis mediates bacterial invasion into human endothelial cells; Lahteenmaki K et al.; The plasminogen activator Pla of Yersinia pestis belongs to the omptin family of enterobacterial surface proteases and is responsible for the highly efficient invasion of the plague bacterium from the subcutaneous infection site into the circulation . Y . pestis has been reported to invade human epithelial cells . Here, we investigated the role of Pla in bacterial invasion into human endothelial cells . Expression of Pla in recombinant Escherichia coli XL1(pMRK1) enhanced bacterial invasion into ECV304 cells . The invasiveness was not affected by substitution mutation at the residues S99 or D206 that are needed for the proteolytic activity of Pla . Pla-expressing bacteria adhered to the extracellular matrix of ECV304 cells . Only weak adhesion and poor invasion were seen with the recombinant E . coli XL1(pMRK2), which expresses the omptin homolog from E . coli . The results identify Pla as an invasion protein of Y . pestis and show that the invasive function does not involve the proteolytic activity of Pla.

Klin Lab Diagn, 2001 Jun, (6), 47 - 50
{Use of bentonite clays as accumulation media for enterobacteria}; Buzoleva LS; Bentonite media consisting of phosphate saline buffer and bentonite corpuscles of certain size are proposed as accumulation media for Enterobacteriaceae . The "attitude" of the studied bacteria to bentonite particles of different size is selective . Salmonella and Shigella multiply in medium consisting of 0.001 mm particles in 1% concentration similarly as in common growth media . The growth of Yersinia in medium of 0.05-mm corpuscles in 1% concentration was 3 Lg higher than in common growth medium . Bentonite media are cheap, easily available, and economic in comparison with common accumulation media.

Int J Antimicrob Agents, 2001 Aug, 18(2), 99 - 106
Antibiotic sensitivity still prevails in Norwegian blood culture isolates; Leegaard TM et al.; We describe the antimicrobial susceptibility of bacteraemia isolates from Norway . From March 1998 to February 1999, four university hospitals covering all parts of Norway collected their first 10 isolates each month . Minimal inhibitory concentrations were determined for: Enterobacteriaceae (n=192), staphylococci (n=89) and Streptococcus pneumoniae (n=69) using the Etest . NCCLS breakpoints were used . About 20% of all blood culture isolates in Norway in this period were investigated . Compared with countries outside Scandinavia antibiotic sensitivity still prevails . Only minor differences in resistance were found between participating hospitals, between hospital departments and between hospital- and community-acquired pathogens . The prudent use of antibiotics in Norway may contribute to the fact that antibiotic resistance still remains low in the most common bacterial pathogens causing bloodstream infections.

Philos Trans R Soc Lond B Biol Sci, 2001 Jul 29, 356(1411), 1027 - 34
Acquisition of virulence-associated factors by the enteric pathogens Escherichia coli and Salmonella enterica; Wain J et al.; In this review we summarize recent genomic studies that shed light on the mechanism through which pathogenic Escherichia coli and Salmonella enterica have evolved . We show how acquisition of DNA at specific sites on the chromosome has contributed to increased genetic variation and virulence of these two genera of the Enterobacteriaceae.

J Hosp Infect, 2001 Sep, 49(1), 69 - 73
Surveillance of hospital-acquired infection in the Republic of Ireland: past, present and future; Humphreys H et al.; There is increasing interest in the surveillance of hospital-acquired infection (HAI) in the Republic of Ireland due to a greater awareness of the consequences of antibiotic resistance, and consumer pressure in the form of public expectations of the quality of health care . To date there have been no nationwide prospective surveillance projects but surveillance has taken place in the form of participation in international and national studies, and the description of local outbreaks . Infection control teams and others have participated in projects such as a European study of HAI in intensive care units conducted in 1992, the second national prevalence study conducted in the UK in 1993 and two surveys of methicillin-resistant Staphylococcus aureus (MRSA) carried out in 1995 and 1999, the latter involving colleagues in Northern Ireland . There have been a number of local surveys of antibiotic-resistant bacteria including the molecular characterization of MRSA in Dublin hospitals, vancomycin-resistant enterococci, and Gram-negative bacteria such as Enterobacter spp . and Serratia spp . affecting compromised patients such as bone marrow transplant recipients . In the future, it is hoped to standardize case definitions, automate data entry, increase collaboration with surveillance initiatives in Northern Ireland and link in with European networks such as EARSS and HELICS . Apart from the need to improve the quality of health care in Irish hospitals, approximate costings suggest that there are potential savings of 7.5 pounds sterling -15 pounds sterling m to be made following a reduction of HAI rates of 15% .

Tunis Med, 2001 Apr, 79(4), 242 - 6
{Epidemiology of urinary infections in the Menzel-Bourguiba region: 933 cases}; Larabi K; The author presents a study about epidemiology of urinary tract infection (UTI) diagnosed in Menzel-Bourguiba hospital laboratory . These UTI are frequent (933 in 18 months) and often concern ambulatory practice (63.4%) . UTI in hospital (36.6%) are most frequent in internal medicine unit (15.9%) and in pediatric unit (7.2%) . The UTI are most frequent in female gender (sex ratio F/H = 3.0) . The most frequent isolates are Enterobacteriacae family (91.7%), and E . coli the major species (73.7%) . Resistances to beta-lactams are frequent either concerning hospital strains or ambulatory patients strains . Beta-lactams family are the most used antibiotics (80% of prescriptions) . In hospital, some isolates were shown to possess extended spectrum betalactamase, but these strains became confined in the unit where appear because of the architectural conception of the hospital (pavilion system) . Aminoglycosids and fluoroquinolones are very active antibiotics, but cotrimoxazole resistance is frequent . Consequently, before any prescription, it would be necessary an antimicrobial susceptibility study, either for hospital UTI, or for UTI in ambulatory practice.

Eur Respir J, 2001 Jul, 18(1), 157 - 63
Diagnosis of nosocomial pneumonia in medical ward: repeatability of the protected specimen brush; Herer B et al.; The aims of this study were to assess the repeatability of two pairs of protected specimen brushes (PSB) done successively in the same lung area and either processed at the bedside or in the laboratory, and to provide a description of the bacteriological findings in 39 cases of suspected nosocomial pneumonia occurring in nonventilated patients . Four PSB were divided into two pairs . One pair of brushes (PB) was prepared at bedside and then sent to the laboratory; the other pair (PL) was immediately sent to the laboratory for complete processing . According to a 10(3) colony forming units (cfu) x mL(-1) threshold, 49% out of 156 PSB were positive . Using the 10(3) cfu x mL threshold, the PL brushes were 89.7% concordant while the PB brushes were 76.9% concordant . The repeatability as expressed by K-value of the cultures of PSB was higher for PL brushes than for PB brushes (K-values of 0.795 and 0.537 respectively, p=0.12) . Bacterial species were isolated in 58.3% of 156 PSB (176 isolates) . In 14 cases, cultures of PSB disclosed more than one micro-organism in a concentration > 10(3) cfu x mL(-1) . The most frequently isolated organisms were Pseudomonas spp . (23.9%), Enterobacteriaceae (23.3%), Streptococcus spp . (21.6%) and Staphylococcus spp . (13.1%) . Polymicrobial cultures were more frequent if the patient had a tracheostomy (seven out of the nine patients with a tracheostomy versus seven out of the 30 patients without a tracheostomy, p<0.01) . Bacteriological discrepancies leading to a potential troublesome choice in antibiotherapy were observed in 31.8% of the patients for PL brushes and 56.5% of the patients for PB brushes . There is a low degree of repeatability of protected specimen brushes outside intensive care units which seem dependent on sampling processing . The distribution of pathogens found in case of suspicion of nosocomial pneumonia in nonventilated patients appears to be similar to that obtained in ventilator-associated pneumonia.

Bioorg Med Chem, 2001 Aug, 9(8), 2035 - 44
Design, synthesis, and evaluation of alpha-ketoheterocycles as class C beta-lactamase inhibitors; Kumar S et al.; A series of specific alpha-ketoheterocycles (benzoxazole, thiazole, imidazole, tetrazole, and thiazole-4-carboxylate) has been synthesized in order to assess their potential as beta-lactamase inhibitors . The syntheses were achieved either by construction of the heterocycle (benzoxazole) from an appropriate alpha-hydroxyimidate, followed by oxidation of the alcohol, or by direct reaction of methyl phenaceturate with a lithiated heterocycle . The properties of these compounds in aqueous solution are described and their inhibitory activity against beta-lactamases assessed . They did inhibit the class C beta-lactamase of Enterobacter cloacae P99 but not the TEM beta-lactamase . The most effective inhibitor of the former enzyme (K(i)=0.11 mM) was 5-(phenylacetylglycyl) tetrazole, probably because it is an anion at neutral pH . Interpretation of the results was aided by computational models of the tetrahedral adducts . Most of the compounds also inhibited alpha-chymotrypsin but not porcine pancreatic elastase.

J Chem Ecol, 2001 Jul, 27(7), 1315 - 31
Importance of bacterial decomposition and carrion substrate to foraging brown treesnakes; Jojola-Elverum SM et al.; Brown treesnakes are an invasive species to the island of Guam that have caused extensive ecological and economic damage . Efforts to control the snake population have included trapping using live mouse lures, but for logistical and economic reasons a synthetic lure is needed . When searching for live food, brown treesnakes use both visual and odor cues . However, when searching for carrion, odor cues are sufficient . Attempts to develop synthetic lures based on chemical reconstruction of the complex carrion odor have not succeeded . We provide evidence that a microbial-substrate interaction is important for bait take by brown treesnakes . Microbial cultures taken from mouse carrion indicate that Enterobacter agglomerans is the predominant bacterium, and field tests suggest that this organism may be important to odor production that attracts brown treesnakes . This information may prove useful in the development of microbial-based biological reactors that could be formulated to produce a continuous stream of odor of sufficient complexity so as to be attractive to foraging snakes.

Antimicrob Agents Chemother, 2001 Sep, 45(9), 2658 - 61
Integrons and gene cassettes in the enterobacteriaceae; White PA et al.; Integrons were detected in 59 of 120 (49%) urinary isolates of Enterobacteriaceae by PCR using degenerate primers targeted to conserved regions of class 1, 2, and 3 integrase genes . PCR sequencing analysis of the cassette arrays revealed a predominance of cassettes that confer resistance to the aminoglycosides and trimethoprim.

Antimicrob Agents Chemother, 2001 Sep, 45(9), 2628 - 30
Risk factors for emergence of resistance to broad-spectrum cephalosporins among Enterobacter spp; Kaye KS et al.; Among 477 patients with susceptible Enterobacter spp., 49 subsequently harbored third-generation cephalosporin-resistant Enterobacter spp . Broad-spectrum cephalosporins were independent risk factors for resistance (relative risk {OR} = 2.3, P = 0.01); quinolone therapy was protective (OR = 0.4, P = 0.03) . There were trends toward decreased risk for resistance among patients receiving broad-spectrum cephalosporins and either aminoglycosides or imipenem . Of the patients receiving broad-spectrum cephalosporins, 19% developed resistance.

Diagn Microbiol Infect Dis, 2001 Jul, 40(3), 129 - 36
Epidemiology and frequency of resistance among pathogens causing urinary tract infections in 1,510 hospitalized patients: a report from the SENTRY Antimicrobial Surveillance Program (North America); Mathai D et al.; Bacterial urinary tract infections (UTIs) are an important cause of septicemia resulting in high mortality rates, prolonged hospital stays and increased healthcare costs . Periodic reviews of pathogen frequency and susceptibility patterns impact on appropriate antimicrobial usage, leading to more effective prescribing practices . As part of the SENTRY Antimicrobial Surveillance Program (SENTRY, 1998), participants collected 50 consecutive UTI pathogens from patients hospitalized in 31 medical centers (26 in the United States and five in Canada) and forwarded subcultures to the coordinating center . Thirty-four antimicrobial agents were tested including two investigational compounds (quinupristin/dalfopristin {Q/D}, gatifloxacin) . The rank order of the 32 species identified during the study was: Escherichia coli (46.9%) > Enterococcus spp . (12.8%) > Klebsiella spp . (11.0%) > Pseudomonas aeruginosa (7.5%) > Proteus mirabilis (5.0%) > coagulase-negative staphylococci (CoNS; 3.4%) . This pathogen rank order did not change from 1997 to 1998, but resistance patterns changed . Clonal spread of confirmed extended spectrum beta-lactamase-producing strains was not observed, but co-resistance was elevated for aminoglycosides, tetracyclines, sulfonamides, and fluoroquinolones . P . aeruginosa was most susceptible to amikacin (97.3%) > piperacillin +/- tazobactam (92.0-95.6%) > cefepime = imipenem (91.2%) > ceftazidime (85.8%) . Fluoroquinolone resistance was greater in P . aeruginosa (24.8-39.8%) > P . mirabilis (5.3-13.3%) > Enterobacter spp . (6.7-8.9%) > Klebsiella spp . (4.2-7.8%) > E . coli (3.0-3.8%) . Only 5% of enterococci were resistant to vancomycin . These results emphasize the need for continued surveillance studies for common infections which establish baseline resistance patterns by geographic areas, and have the potential to detect epidemics or direct local epidemiologic interventions.

Int J Syst Evol Microbiol, 2001 Jul, 51(Pt 4), 1291 - 304
Samsonia erythrinae gen . nov., sp . nov., isolated from bark necrotic lesions of Erythrina sp., and discrimination of plant-pathogenic Enterobacteriaceae by phenotypic features; Sutra L et al.; Bacterial strains isolated from diseased erythrina (Erythrina sp.) trees in Martinique (French West Indies) were studied using phenotypic tests, 16S rDNA sequence analysis and DNA-DNA hybridization . Numerical analysis of phenotypic characteristics showed that these strains formed an homogeneous phenon among plant-pathogenic Enterobacteriaceae, and gave useful and updated information for the identification of these bacteria . Results of DNA-DNA hybridization indicated that strains from erythrina belonged to a discrete genomospecies (89-100% hybridization) and had low levels of DNA relatedness (2-33% hybridization) with reference strains of phytopathogenic Erwinia, Brenneria, Pectobacterium, Pantoea and Enterobacter species . 16S rDNA sequence analysis using three different methods revealed that the position of strain CFBP 5236T isolated from erythrina was variable in the different trees, so that strains from erythrina could not be assigned to any recognized genus . It is proposed that these strains are included in a new genus, Samsonia . The name Samsonia erythrinae is proposed for the new species . The G+C content of the DNA of the type strain, CFBP 5236T (= ICMP 13937T), is 57.0 mol%.

J Immunol, 2001 Aug 15, 167(4), 2250 - 6
Protective roles of mast cells against enterobacterial infection are mediated by Toll-like receptor 4; Supajatura V et al.; Toll-like receptors (TLRs) are mammalian homologues of the Drosophila Toll receptors and are thought to have roles in innate recognition of bacteria . We demonstrated that TLR 2, 4, 6, and 8 but not TLR5 were expressed on mouse bone marrow-derived mast cells (BMMCs) . Using BMMCs from the genetically TLR4-mutated strain C3H/HeJ, we demonstrated that functional TLR4 was required for a full responsiveness of BMMCs to produce inflammatory cytokines (IL-1beta, TNF-alpha, IL-6, and IL-13) by LPS stimulation . TLR4-mediated stimulation of mast cells by LPS was followed by activation of NF-kappaB but not by stress-activated protein kinase/c-Jun NH2-terminal kinase signaling . In addition, in the cecal ligation and puncture-induced acute septic peritonitis model, we demonstrated that genetically mast cell-deficient W/W(v) mice that were reconstituted with TLR4-mutated BMMCs had significantly higher mortality than W/W(v) mice reconstituted with TLR4-intact BMMCs . Higher mortality of TLR4-mutated BMMC-reconstituted W/W(v) mice was well correlated with defective neutrophil recruitment and production of proinflammatory cytokines in the peritoneal cavity . Taken together, these observations provide definitive evidence that mast cells play important roles in exerting the innate immunity by releasing inflammatory cytokines and recruitment of neutrophils after recognition of enterobacteria through TLR4 on mast cells.

Eur J Biochem, 2001 Aug, 268(15), 4233 - 42
Interaction of hemoglobin with enterobacterial lipopolysaccharide and lipid A . Physicochemical characterization and biological activity; Jurgens G et al.; The interaction of hemoglobin (Hb) with endotoxins {i.e . with enterobacterial deep rough mutant lipopolysaccharide (LPS) Re and the "endotoxic principle" of LPS, lipid A} was investigated using a variety of physical techniques and with two biological assays, tumor necrosis factor (TNF)-alpha induction in human mononuclear cells and the Limulus amebocyte lysate (LAL) assay . Fourier-transform IR-spectroscopic experiments indicate nonelectrostatic binding to the hydrophobic moiety with a slight rigidification of the lipid A acyl chains, and an increase in the inclination of the lipid A backbone with respect to the membrane surface from 35 degrees to more than 40 degrees due to Hb binding, but no change of the predominantly alpha-helical secondary structures of Hb due to LPS binding . From isothermal titration calorimetry, the molar {Hb} : {endotoxin} binding ratio lies between 1 : 3 and 1 : 5 molar . Synchrotron radiation X-ray diffraction measurements indicate a reorientation of the lipid A aggregates from one cubic structure to another, the final structure belonging to space group Q224 . The LPS-induced TNF-alpha production of mononuclear cells is enhanced by Hb, whereas in the LAL assay an LPS concentration-dependent increase or decrease was observed . Although a detailed mechanism of action cannot be given, the enhancement of LPS bioactivity can be understood in the light of the previously presented conformational concept; Hb induces an increase in the conical shape of the lipid A moiety of LPS, higher cross-section of the hydrophobic than the hydrophilic part, and of the inclination angle of the diglucosamine backbone with respect to the direction of the acyl chains.

Klin Lab Diagn, 2000 Nov, (11), 39 - 42
{Clinico-laboratory parallels during celiac disease in children}; Kamilova AT et al.; Forty-five patients with celiac disease and 73 with the celiakia syndrome were observed . The clinical picture was identical and was characterized by disordered intestinal absorption . Depression of T and B lymphocytes was typical of both forms of the disease . High values of antigliadin IgA and IgG correlated with the severity of atrophic processes in the small intestinal mucosa . Intestinal microflora was characterized by a decrease in the main defense flora and growth of hemolytical and lactonegative enterobacteria and Proteus . Hypocholesterolemia was characteristic of congenital and acquired celiakia . Hemoglobin and albumin levels were in direct correlation while growth deficiency and increment of glycemia were in inverse correlation in patients with celiac disease . The celiakia syndrome was characterized by an inverse correlation between the number of defecations and content of full-value E . coli, body weight deficit, and glucose tolerance test.

Int J Food Microbiol, 2001 Jul 20, 67(1-2), 115 - 22
Utilization at high pH of starter cultures of lactobacilli for Spanish-style green olive fermentation; Sanchez AH et al.; Inoculation at alkaline pH (above 9) of lye-treated green olives with starter cultures of Lactobacillus pentosus CECT 5138 was studied . Despite an initial loss of viability in the order of 1-2 log cycles on average, depending mainly on time of application, cultures grew and initiated an accelerated fermentation process . Inoculation reduced the population of Enterobacteriaceae, and thereby potential spoilage, and produced a quicker acidification of brines and decrease of pH, when compared with control uninoculated batches . Results obtained throughout three consecutive seasons demonstrated that utilization at high pH of starter cultures of lactobacilli is feasible, provided that the inoculum size takes into account the initial low survival.

Proc Natl Acad Sci U S A, 2001 Aug 14, 98(17), 9871 - 6 Epub 2001 Jul 31.
Polar targeting of Shigella virulence factor IcsA in Enterobacteriacae and Vibrio; Charles M et al.; Asymmetric localization is key to the proper function of certain prokaryotic proteins important to virulence, chemotaxis, cell division, development, motility, and adhesion . Shigella IcsA is localized to the old pole of the bacterium, where it mediates assembly of an actin tail inside infected mammalian cells . IcsA (VirG) is essential to Shigella intracellular motility and virulence . We used translational fusions between portions of IcsA and the green fluorescent protein (GFP) to determine the regions of IcsA that are necessary and sufficient for its targeting to the bacterial old pole . An IcsA-GFP fusion that lacks a signal peptide localized to the old pole, indicating that signal peptide-mediated secretion is not required for polar localization . Two regions within IcsA were required for localization of an IcsA-GFP fusion to the old pole . Further characterization of these regions indicated that amino acids 1-104 and 507-620 were each independently sufficient for polar localization . Finally, when expressed in Escherichia coli, Salmonella typhimurium, Yersinia pseudotuberculosis, and Vibrio cholerae, each of the two targeting regions localized to the pole, indicating that the mechanism of polar targeting used by IcsA is present generally among Enterobacteriacae and Vibrio.

Arch Microbiol, 2001 Jul, 176(1-2), 151 - 4
The methionine biosynthetic pathway from homoserine in Pseudomonas putida involves the metW, metX, metZ, metH and metE gene products; Alaminos M et al.; Biosynthesis of methionine from homoserine in Pseudomonas putida takes place in three steps . The first step is the acylation of homoserine to yield an acyl-L-homoserine . This reaction is catalyzed by the products of the metXW genes and is equivalent to the first step in enterobacteria, gram-positive bacteria and fungi, except that in these microorganisms the reaction is catalyzed by a single polypeptide (the product of the metA gene in Escherichia coli and the met5 gene product in Neurospora crassa) . In Pseudomonas putida, as in gram-positive bacteria and certain fungi, the second and third steps are a direct sulfhydrylation that converts the O-acyl-L-homoserine into homocysteine and further methylation to yield methionine . The latter reaction can be mediated by either of the two methionine synthetases present in the cells.

J Clin Microbiol, 2001 Aug, 39(8), 2964 - 6
Evaluation of VITEK 2 rapid identification and susceptibility testing system against gram-negative clinical isolates; Ling TK et al.; A total of 281 strains of miscellaneous members of the family Enterobacteriaceae, Pseudomonas aeruginosa, and other gram-negative bacteria were evaluated by use of identification tests with the VITEK 2 system (bioMerieux) and an API identification system (bioMerieux) . A total of 237 (95%) strains were correctly identified to the species level . Only six (2.1%) strains were misidentified, and eight (2.8%) strains were not identified . Among 14 strains with discrepant identifications, 8 (57.1%) strains were nonfermenters . The susceptibilities of 228 strains to 11 antibiotics including amikacin, netilmicin, tobramycin, gentamicin, ciprofloxacin, imipenem, meropenem, ceftazidime, cefepime, piperacillin, and piperacillin in combination with tazobactam were tested with the VITEK 2 AST-No . 12 card and by the broth microdilution (MB) method, according to NCCLS guidelines, as a reference . For the 2,508 organism-antibiotic combinations, the rates at which duplicate MICs correlated within +/-1 dilution ranged from 84.2 to 95.6% . Only 13 (0.5%) and 10 (0.4%) of the susceptibility tests gave major errors (resistant with the VITEK 2 system but sensitive by the MB method) and very major errors (sensitive with the VITEK 2 system but resistant by the MB method), respectively . Both VITEK 2 ID-GNB (an identification system) and VITEK 2 AST-No . 12 (a susceptibility testing system) card systems gave rapid, reliable, and highly reproducible results.

Microbiol Immunol, 2001, 45(5), 383 - 6
Resistance to antibiotics in injured coliforms isolated from drinking water; Cordoba MA et al.; We studied the antibiotic sensitivity of injured coliforms isolated from drinking water of La Plata, Argentina . The antibiotic sensitivity test by the agar diffusion method were proved in: Klebsiella oxytoca (14 strains), Enterobacter aerogenes (4 strains) and Enterobacter cloacae genomic group 3 (14 strains) . We found that while these impaired total coliforms were sensitive to piperacillin-tazobactam (TAZ), netilmicin (NTL), ofloxacin (OFLX), and norfloxacin (NFLX) (100%), they had resistant to aminopenicillin-sulbactam (AMS) and nitrofurantoin (NIT) (100%) . The resistance to antibiotics demonstrated in these strains would point to the need to promote a rational and judicious use of antimicrobial agents while at the same time implementing a program of active vigilance aimed at ensuring the highest quality of drinking water throughout the system.

Biosci Biotechnol Biochem, 2001 Jun, 65(6), 1399 - 401
Properties of an extracellular polysaccharide produced by a strain of enterobacter isolated from pond water; Isobe Y et al.; A bacterium which was isolated from pond water and identified as Enterobacter cloacae produced a viscous extracellular polysaccharide when it was grown aerobically in a medium containing sucrose as a sole source of carbon . The maximum molecular weight of the polysaccharide was about 9.0 x 10(5) . The polysaccharide was composed of fucose, galactose, glucose, and glucuronic acid in a molar ratio of 2:3:2:1, but the molecular weight and the molar ratio of the sugar component were different from those of the polysaccharide produced by the same species reported elsewhere.

Vet Microbiol, 2001 Sep 28, 82(3), 249 - 59
Development of an ELISA procedure to detect swine carriers of pathogenic Yersinia enterocolitica; Thibodeau V et al.; An enzyme immunoassay (ELISA) was developed to detect antibodies in pigs against the lipopolysaccharidic antigen of the three serotypes of Yersinia enterocolitica mostly associated with human infections . Recent epidemiological evidence has demonstrated that pigs and pork are important sources of yersiniosis in humans . The purpose of this study was to clarify the use of an ELISA to detect swine carriers of this enteroinvasive bacteria by examining seroconversion and tissue distribution of Y . enterocolitica following experimental infection and then screening pigs at a slaughterhouse by bacterial culture and ELISA . It was observed that seroconversion occurred in animals experimentally inoculated with Y . enterocolitica but not with other enterobacteria . It was also found that 27% of swine at a slaughterhouse carried the bacterium in their tonsils and/or intestinal tract, whereas 66% showed serological evidence of previous infection . About 6% of swine at slaughter were culture-positive, but seronegative . Although, similar numbers of swine showed serological evidence of previous infection by each of the three Y . enterocolitica serotypes tested, virtually all culture isolates belonged to serotype O:3 . This ELISA appears as a valuable control tool that can be used, in conjunction with culture, to identify pigs or herds infected by strains of Y . enterocolitica associated with human infections.

FEMS Microbiol Lett, 2001 Jul 24, 201(2), 237 - 41
Plasmid-mediated extended-spectrum beta-lactamase (CTX-M-3 like) from India and gene association with insertion sequence ISEcp1; Karim A et al.; Six non-clonally related enterobacterial isolates producing a same extended-spectrum beta-lactamase CTX-M-15 were isolated in 1999 from patients hospitalized in a New Delhi hospital . CTX-M-15 differed from CTX-M-3 by an asparagine to glycine substitution in position ABL238 . Its gene was located on large plasmids varying in size . In each case, a same insertion sequence ISEcp1 was identified upstream of the 5' end of bla(CTX-M-15) . Typical -35 and -10 promoter sequences of Enterobacteriaceae were identified in the 3' end of ISEcp1 . The location of ISEcp1 upstream of plasmid-mediated CTX-M-type beta-lactamase genes may contribute to their spread or/and their expression.

Int J Antimicrob Agents, 2001 Jul, 18(1), 81 - 3
Identity and antibiotic susceptibility of enterobacterial flora of salad vegetables; Hamilton-Miller JM et al.; The enterobacterial flora from carrots (organic and non-organic) and salad vegetables has been identified and antibiotic susceptibilities determined . Pseudomonas fluorescens and Pantoea (formerly Enterobacter) agglomerans were the species most commonly found; the former was usually resistant to at least six of the antibiotics under test . Rahnella aquatilis (often producing beta-lactamase) was also found in carrots . There were no clear differences in flora from organic and non-organic carrots . Thus, uncooked vegetables are a potential source of highly resistant opportunistic pathogens.

Gynecol Obstet Fertil, 2001 Jun, 29(6), 433 - 9
{Neonatal bacterial infections at the CUH of Dakar}; Cisse CT et al.; OBJECTIVES: It's a retrospective study in order to determine the epidemiology of neonatal bacterial infection and to evaluate the efficiency of the antibiotic protocol in University Teaching Hospital in Dakar . MATERIAL AND METHODES: From January 1st 1997 to December 31st 1998 we have registered 7461 live births, samples of blood are taken from 2312 new-born baby and they received antibiotherapy (beta-lactamine + gentamycin) at the first day based on infections risk evaluated by anamnestic criterias . The treatment is seven to one days long, the antibiotic was adapted according to the antibiogram result . RESULTS: The neonatal infection diagnosis is confirmed in 246 cases, about 33 per 1000 live births or 10.6% of newborn babies having on antibiotherapy . Most current risk factors are premature rupture of membranes (85%) and neonatal suffering (87.8%) . Isolated gerras are: Klebsiella pneumoniae (61.5%), Enterobacteria (11.5 Staphylococcus (8.7%), colibacille (6%), Streptococcus (5.5%), Enterococcus (4.1%) and Pseudomonas (2.7%) . Most of these germs are resistant to antibiotics currently used in first intention (ampicillin, cefotaxim, gentamycin), in particularly 95% of Klebsiella . Most efficient antibiotics are amikacin, colistin, ceftriaxon and ciprofloxacine . Deaths occurs in 48 cases with 36 in early neonatal period, 79% of mortality rate related to infection by Klebsiella . CONCLUSION: First intention antibiotherapy must be always adapted to the bacterial ecology evolution and must be more selective by using major infections risk factors . We promote early infection diagnosis by using biologic markers which reference is represented by C Reactive Protein.

Mol Microbiol, 2001 Jul, 41(1), 189 - 98
A new mechanism of antibiotic resistance in Enterobacteriaceae induced by a structural modification of the major porin; De E et al.; In Enterobacter aerogenes, multidrug resistance involves a decrease in outer membrane permeability associated with changes in an as yet uncharacterized porin . We purified the major porin from the wild-type strain and a resistant strain . We characterized this porin, which was found to be an OmpC/OmpF-like protein and analysed its pore-forming properties in lipid bilayers . The porin from the resistant strain was compared with the wild-type protein and we observed (i) that its single-channel conductance was 70% lower than that of the wild type; (ii) that it was three times more selective for cations; (iii) a lack of voltage sensitivity . These results indicate that the clinical strain is able to synthesize a modified porin that decreases the permeability of the outer membrane . Mass spectrometry experiments identified a G to D mutation in the putative loop 3 of the porin . Given the known importance of this loop in determining the pore properties of porins, we suggest that this mutation is responsible for the novel resistance mechanism developed by this clinical strain, with changes in porin channel function acting as a new bacterial strategy for controlling beta-lactam diffusion via porins.

Antimicrob Agents Chemother, 2001 Aug, 45(8), 2269 - 75
Novel cefotaximase (CTX-M-16) with increased catalytic efficiency due to substitution Asp-240-->Gly; Bonnet R et al.; Three clinical strains (Escherichia coli Rio-6, E . coli Rio-7, and Enterobacter cloacae Rio-9) collected in 1996 and 1999 from hospitals in Rio de Janeiro (Brazil) were resistant to broad-spectrum cephalosporins and gave a positive double-disk synergy test . Two bla(CTX-M) genes encoding beta-lactamases of pl 7.9 and 8.2 were implicated in this resistance: the bla(CTX-M-9) gene observed in E . coli Rio-7 and E . cloacae Rio-9 and a novel CTX-M-encoding gene, designated bla(CTX-M-16), observed in E . coli strain Rio-6 . The deduced amino acid sequence of CTX-M-16 differed from CTX-M-9 only by the substitution Asp-240-->Gly . The CTX-M-16-producing E . coli transformant exhibited the same level of resistance to cefotaxime (MIC, 16 microg/ml) but had a higher MIC of ceftazidime (MIC, 8 versus 1 microg/ml) than the CTX-M-9-producing transformant . Enzymatic studies revealed that CTX-M-16 had a 13-fold higher affinity for aztreonam and a 7.5-fold higher k(cat) for ceftazidime than CTX-M-9, thereby showing that the residue in position 240 can modulate the enzymatic properties of CTX-M enzymes . The two bla(CTX-M-9) genes and the bla(CTX-M-16) gene were located on different plasmids, suggesting the presence of mobile elements associated with CTX-M-encoding genes . CTX-M-2 and CTX-M-8 enzymes were found in Brazil in 1996, and two other CTX-M beta-lactamases, CTX-M-9 and CTX-M-16, were subsequently observed . These reports are evidence of the diversity of CTX-M-type extended-spectrum beta-lactamases in Brazil.

Antimicrob Agents Chemother, 2001 Aug, 45(8), 2215 - 23
Kinetic study of two novel enantiomeric tricyclic beta-lactams which efficiently inactivate class C beta-lactamases; Vilar M et al.; A detailed kinetic study of the interaction between two ethylidene derivatives of tricyclic carbapenems, Lek 156 and Lek 157, and representative beta-lactamases and D-alanyl-D-alanine peptidases (DD-peptidases) is presented . Both compounds are very efficient inactivators of the Enterobacter cloacae 908R beta-lactamase, which is usually resistant to inhibition . Preliminary experiments indicate that various extended-spectrum class C beta-lactamases (ACT-1, CMY-1, and MIR-1) are also inactivated . With the E . cloacae 908R enzyme, complete inactivation occurs with a second-order rate constant, k(2)/K', of 2 x 10(4) to 4 x 10(4) M(-1) s(-1), and reactivation is very slow, with a half-life of >1 h . Accordingly, Lek 157 significantly decreases the MIC of ampicillin for E . cloacae P99, a constitutive class C beta-lactamase overproducer . With the other serine beta-lactamases tested, the covalent adducts exhibit a wide range of stabilities, with half-lives ranging from long (>4 h with the TEM-1 class A enzyme), to medium (10 to 20 min with the OXA-10 class D enzyme), to short (0.2 to 0.4 s with the NmcA class A beta-lactamase) . By contrast, both carbapenems behave as good substrates of the Bacillus cereus metallo-beta-lactamase (class B) . The Streptomyces sp . strain R61 and K15 extracellular DD-peptidases exhibit low levels of sensitivity to both compounds.

FEMS Microbiol Ecol, 2001 Jul, 36(2-3), 169 - 174
Gel sequestration of heavy metals by Klebsiella oxytoca isolated from iron mat; Baldi F et al.; The enterobacterium Klebsiella oxytoca strain BAS-10 was isolated from sediments under an iron mat formed in a stream receiving leached waters from pyrite mine tailings . Under anaerobic laboratory conditions, BAS-10 fermented Fe(III)-citrate and Na-citrate giving CH(3)COOH and CO(2) . In the presence of ferric citrate, BAS-10 secreted quantities of a thick gel containing glucose and/or mannose, if not other sugars . Sugar residues were observed in microbial aggregates using the sugar-specific concanavalin A lectin conjugated with fluorescein and imaged by a scanning confocal laser microscope . The gel bound Fe(III) which quickly precipitated . During fermentation, however, half the initial Fe(III) concentration was reduced to Fe(II) which did not bind to the gel and remained in solution . BAS-10 showed a high tolerance to heavy metals . Its growth was not inhibited by 1 mM Zn-, Pb- or Cd-acetate . These cations also co-precipitated with the iron gel, suggesting a possible application of this strain for abatement of toxic metals under anaerobic conditions.

FEMS Microbiol Ecol, 2001 Jul, 36(2-3), 153 - 164
Multitude and temporal variability of ecological niches as indicated by the diversity of cultivated bacterioplankton; Jaspers E et al.; The diversity of cultured planktonic bacteria was analyzed . Bacterial strains were isolated from a eutrophic lake (Zwischenahner Meer, Niedersachsen, Germany) at three different sampling dates (October 1997, April and May 1998) . Phylogenetic diversity was assessed by polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and sequencing of 16S rRNA gene fragments . Enterobacterial repetitive intergenic consensus (ERIC)-PCR revealed a high genomic diversity within the strain collections, which exceeded the diversity of the 16S rRNA gene sequences considerably . The composition of each of the three strain collections was unique since strains isolated at different dates always exhibited different ERIC-PCR fingerprints . Growth tests with 59 different carbon substrates demonstrated that even strains with identical ERIC-PCR fingerprints, isolated on one sampling date, differed in their physiology . The culturable fraction investigated in the present study constituted a relatively small fraction (</=15%) of the whole bacterioplankton assemblage . Nevertheless, the high physiological diversity in this fraction already indicates that a multitude of different ecological niches must exist in the planktonic environment . The majority of strains isolated in April prior to the decay of the phytoplankton bloom were members of the Cytophaga-Flavobacterium group . One month later, not a single strain of this group could be isolated . When a group-specific PCR-DGGE technique was employed, rapid shifts in the diversity of non-cultured Cytophaga-Flavobacteria also became evident . Based on the rapid shifts in the composition of cultivated as well as some non-cultivated bacteria, the ecological niches in the planktonic habitat must undergo rapid temporal changes.

Biochem Biophys Res Commun, 2001 Jul 13, 285(2), 526 - 9
Kinetic mechanism and identification of the active site tyrosine residue in Enterobacter amnigenus arylsulfate sulfotransferase; Kwon AR et al.; Bacterial arylsulfate sulfotransferase (ASST) catalyzes the transfer of a sulfate group from a phenyl sulfate ester to a phenolic acceptor . The kinetic mechanism of Enterobacter amnigenus ASST was determined . Plots of 1/v versus 1/{substrate (A)} at different fixed substrate (B) concentrations gave a series of parallel lines . One of the reaction products, p-nitrophenol, inhibited the enzyme noncompetitively with respect to p-nitrophenyl sulfate, but competitively to alpha-naphthol . These results correspond to a ping pong bi bi mechanism . By site-directed mutagenesis, we substituted each conserved tyrosine residue with phenylalanine . Among the mutants, Y123F showed severely reduced catalytic activity . We conclude that Tyr 123 is an essential active site residue . A mechanistic hypothesis is presented to account for these observations .

J Bacteriol, 2001 Aug, 183(15), 4395 - 404
Transposition of IS1397 in the family Enterobacteriaceae and first characterization of ISKpn1, a new insertion sequence associated with Klebsiella pneumoniae palindromic units; Wilde C et al.; IS1397 and ISKpn1 are IS3 family members which are specifically inserted into the loop of palindromic units (PUs) . IS1397 is shown to transpose into PUs with sequences close or identical to the Escherichia coli consensus, even in other enterobacteria (Salmonella enterica serovar Typhimurium, Klebsiella pneumoniae, and Klebsiella oxytoca) . Moreover, we show that homologous intergenic regions containing PUs constitute IS1397 transpositional hot spots, despite bacterial interspersed mosaic element structures that differ among the three species . ISKpn1, described here for the first time, is specific for PUs from K . pneumoniae, in which we discovered it . A sequence comparison between the two insertion sequences allowed us to define a motif possibly accounting for their specificity.

Indian J Public Health, 2000 Oct-Dec, 44(4), 111 - 7
Extents of contamination of top milk and their determinants in an urban slum of Varanasi, India; Ray G et al.; A community based study to examine the extent of contamination of supplementary milk feeds of 149 children aged 6-24 months was conducted in a semi urban slum of Varanasi, India . Out of 201 children, 149 top milk samples were collected directly from the feeding utensils into a sterile vial and subjected to bacteriological analysis . Overall, 53.7% of milk samples were contaminated by bacteria and among them 16.1% were potentially enteropathogenic in nature . The distribution of pathogens was E . coli (13.4%), Klebsiella spp (5.4%), Enterobacter spp . (5.4%), Pseudomonas aeruginosa (4.7%), Shigella spp . (2.7%) and others (22.1%) . The rate of contamination was significantly higher (p < 0.001) in lower income group (73.4%), lower caste (69.6%) and in case of illiterate mothers (69.3%) . Bivariate analysis indicated that wherever the afore mentioned parameters of hygiene were adverse, isolation rates increased multifoldely . Multiple logistic regression analysis indicated that the probability of a milk sample being positive for bacterial contamination was higher by 20 times when unclean utensils were used, by 3 times if mothers hands were dirty and by 2.8 time if the mothers were illiterate . The odds of contamination by pathogens was 25.7 times higher if the feeding utensils were dirty.

J Toxicol Environ Health A, 2001 Jun 22, 63(4), 297 - 316
Oral treatment of Fischer 344 rats with weathered crude oil and a dispersant influences intestinal metabolism and microbiota; George SE et al.; When oil is spilled into aquatic systems, chemical dispersants frequently are applied to enhance emulsification and biological availability . In this study, a mammalian model system was used to determine the effect of Bonnie Light Nigerian crude oil, weathered for 2 d with continuous spraying and recirculation, and a widely used dispersant, Corexit (Cx) 9527, on intestinal microbial metabolism and associated populations . To determine the subchronic dose, concentrated or diluted (1:2, 1:5, 1:10, 1:20) Cx9527 or oil was administered by gavage to Fischer 344 rats and the effect on body weight was determined . Next, rats were treated for 5 wk with oil, dispersant, or dispersant + oil . Body and tissue weights, urine mutagenicity, and the impact on the intestinal microflora and three microbial intestinal enzymes linked to bioactivation were determined in the small and large intestines and cecum . Two tested dispersants, Cx9527 and Cx9500, were toxic in vitro (1:1,000 dilution), and oil was not mutagenic in strains TA98 and TA100(+/-S9) . None of the treated rats produced urine mutagens detected by TA98 or TA100 . Undiluted dispersant was lethal to rats, and weight changes were observed depending on the dilution, whereas oil generally was not toxic . In the 5-wk study, body and tissue weights were unaffected at the doses administered . Small-intestinal levels of azoreductase (AR), beta-glucuronidase (BG), and nitroreductase (NR) were considerably lower than cecal and large-intestinal activities at the same time point . A temporal increase in AR activity was observed in control animals in the 3 tissues examined, and large-intestinal BG activity was elevated in 3-wk controls . No significant changes in cecal BG activity were observed . Oil- or dispersant-treated rats had mixed results with reduced activity at 3 wk and elevated activity at 5 wk compared to controls . However, when the dispersant was combined with oil at 3 wk, a reduction in activity was observed that was similar to that of dispersant alone . One-week nitroreductase activity in the small intestine and cecum was unaffected in the three treatment groups, but elevated activity was observed in the large intestines of animals treated with oil or dispersant . The effect of the combination dose was not significantly different from the control value . Due to experimental error, no 3- or 5-wk NR data were available . By 5 wk of treatment, enterobacteria and enterococci were eliminated from ceca of oil-treated rats . When oil was administered in combination with dispersant, an apparent protective effect was observed on the enterococci and lactose-fermenting and nonfermenting enterobacteria . A more detailed analysis at the species level revealed qualitative differences dependent on the treatment . This study suggests that prolonged exposure of mammals to oil, dispersant, or in combination impacts intestinal metabolism, which ultimately could lead to altered detoxification of oil constituents and coexposed toxicants.

Gac Med Mex, 2001 May-Jun, 137(3), 191 - 202
{Trends for bacteremia and risk factors for death in a tertiary hospital in Mexico City . 1981-1992}; Sifuentes-Osornio J et al.; OBJECTIVE: To describe the trends and risk factors of death for bacteremia in adult from a tertiary-care center from 1981 to 1992 . MATERIAL AND METHODS: We randomly included 20% of bacteremic episodes per year . RESULTS: 47,618 blood-cultures from 19,530 patients, 3428 patients (17.6%) had bacteremia (285/y) . From 600 episodes (50/y), 307 were from men, 368 were hospital-acquired (HA), and 88% were monomicrobial . Diabetes mellitus was seen in 103 cases, cirrhosis of the liver in 98, and AIDS in 33, among others . The main microorganisms were: Escherichia coli (177), Klebsiella pneumoniae (53), Enterobacter (50), Salmonella (45) and Pseudomonas aeruginosa (35); coagulase-negative staphylococci (CNS) (116), Staphylococcus aureus (56), and enterococci (22), and Candida (20) . CNS decreased during the study (p < 0.01), but Candida spp., Stenotrophomonas maltophilia and enterococci increased (p < 0.01) . The crude mortality of the HA bacteremia was 70.8%, and 29.2% in the case of community-acquired, the mortality attributable to HA bacteremia was 41.6% . The main risk factors were: cardiac valvular disease (p < 0.001), stay at the intensive-care unit (p < 0.001), sepsis (p < 0.001), and pneumonia (p < 0.001) . DISCUSSION: Bacteremia had a significant impact on mortality during the study period that has not change despite opportune therapy, Enterococci and candida have emerged as significant pathogens.

Int J Food Microbiol, 2001 Jun 15, 66(3), 185 - 9
Amino acid-decarboxylase activity of bacteria isolated from fermented pork sausages; Bover-Cid S et al.; The occurrence of amino acid-decarboxylase activity in 92 strains of lactic acid bacteria, coagulase-negative staphylococci, and Enterobacteriaceae isolated from Spanish fermented pork sausages was investigated . The presence of biogenic amines in a decarboxylase synthetic broth was determined by ion-pair high performance liquid chromatography with o-phtalaldehyde post-column derivatization . Among the 66 lactic acid bacteria strains tested, 21 lactobacilli (in particular, Lactobacillus curvatus) and all 16 enterococci were amine producers . Tyramine was the main amine produced by these bacteria, although they also produced phenylethylamine, tryptamine, and/or the diamines putrescine and cadaverine . None of the lactic acid bacteria produced histamine . Coagulase-negative staphylococci were found to be negative amine-producers . Aromatic monoamines, apart from histamine, were not formed by Enterobacteriaceae . This family was responsible for cadaverine and putrescine production . The results obtained for biogenic amine production by bacteria in a synthetic medium suggest that amino acid-decarboxylase activity is strain dependent rather than being related to specific species.

Int J Food Microbiol, 2001 Jun 15, 66(3), 175 - 84
Characterisation of volatile compounds produced by bacteria isolated from the spoilage flora of cold-smoked salmon; Joffraud JJ et al.; This study investigated the volatile compounds produced by bacteria belonging to nine different bacterial groups: Lactobacillus sake, L . farciminis, L . alimentarius, Carnobacterium piscicola, Aeromonas sp., Shewanella putrefaciens, Brochothrix thermosphacta, Photobacterium phosphoreum and Enterobacteriaceae isolated from cold-smoked salmon . Each bacterial group was represented by several strains . In addition, combinations of the groups were examined as well . Sterile blocks of cold-smoked salmon were inoculated, vacuum-packed and stored at 6 degrees C . After 40 days of storage at 6 degrees C, aerobic viable count and pH were recorded, the volatile fraction of the samples was analysed by gas chromatography-mass spectrometry (GC-MS), and spoilage was assessed by sensory evaluation . Among the 81 volatile compounds identified by GC-MS, 30 appeared to be released as a result of bacterial metabolism . Some of the effects of inoculated bacterial strains on the composition of the volatile fraction seemed to be characteristic of certain bacterial species . Sensory analysis showed relationships between bacteria, the composition of the volatile fraction and the organoleptic quality of smoked salmon.

J Clin Microbiol, 2001 Jul, 39(7), 2627 - 33
Specific detection of Pasteurella multocida in chickens with fowl cholera and in pig lung tissues using fluorescent rRNA in situ hybridization; Mbuthia PG et al.; A Pasteurella multocida species-specific oligonucleotide probe, pmhyb449, targeting 16S rRNA was designed and evaluated by whole-cell hybridization against 22 selected reference strains in animal tissues . It differentiated P . multocida from other bacterial species of the families Pasteurellaceae and Enterobacteriaceae and also from divergent species of the order Cytophagales (except biovar 2 strains of Pasteurella avium and Pasteurella canis, which have high 16S rRNA similarity to P . multocida) . The potential of the probe for specific identification and differentiation of P . multocida was further detected in formalin-fixed paraffin-embedded lung tissues from experimental fowl cholera in chickens and infections in pigs . In chicken lung tissues P . multocida cells were detected singly, in pairs, as microcolonies, and as massive colonies within air capillaries (septa and lumen), parabronchial septa, and blood vessels (wall and lumen) . In pig lung, postmortem-injected P . multocida was detected in the alveoli (lumen and wall), and in both animals the bacterial cells were seen in the bronchi . The results showed that with the oligonucleotide probe pmhyb449, fluorescent in situ hybridization is a suitable and fast method for specific detection of P . multocida in histological formalin-fixed tissues . The test was replicable and reproducible and is recommended as a supplementary test for diagnosis and as a tool in pathogenesis studies of fowl cholera and respiratory tract infections in pigs due to P . multocida.

J Clin Microbiol, 2001 Jul, 39(7), 2379 - 85
Potential impact of the VITEK 2 system and the Advanced Expert System on the clinical laboratory of a university-based hospital; Sanders CC et al.; A study was designed to assess the impact of the VITEK 2 automated system and the Advanced Expert System (AES) on the clinical laboratory of a typical university-based hospital . A total of 259 consecutive, nonduplicate isolates of Enterobacteriaceae members, Pseudomonas aeruginosa, and Staphylococcus aureus were collected and tested by the VITEK 2 system for identification and antimicrobial susceptibility testing, and the results were analyzed by the AES . The results were also analyzed by a human expert and compared to the AES analyses . Among the 259 isolates included in this study, 245 (94.6%) were definitively identified by VITEK 2, requiring little input from laboratory staff . For 194 (74.9%) isolates, no inconsistencies between the identification of the strain and the antimicrobial susceptibility determined by VITEK 2 were detected by the AES . Thus, no input from laboratory staff was required for these strains . The AES suggested one or more corrections to results obtained with 65 strains to remove inconsistencies . The human expert thought that most of these corrections were appropriate and that some resulted from a failure of the VITEK 2 system to detect certain forms of resistance . Antimicrobial phenotypes assigned to the strains by the AES for beta-lactams, aminoglycosides, quinolones, macrolides, tetracyclines, and glycopeptides were similar to those assigned by the human expert for 95.7 to 100% of strains . These results indicate that the VITEK 2 system and AES can provide accurate information in tests for most of the clinical isolates examined and remove the need for human analysis of results for many . Certain problems were identified in the study that should be remediable with further work on the software supporting the AES.

Appl Environ Microbiol, 2001 Jul, 67(7), 3071 - 6
Effect of fermented feed on the microbial population of the gastrointestinal tracts of pigs; van Winsen RL et al.; An in vivo experiment was performed with pigs to study the inhibitory effect of fermented feed on the bacterial population of the gastrointestinal tract . Results demonstrated a significant positive correlation between pH and lactobacilli in the stomach contents of pigs in dry feed as well as in the stomach contents of pigs fed fermented feed . Furthermore, a significant positive correlation between the pH and the numbers of bacteria in the family Enterobacteriaceae in the contents of the stomach of pigs fed dry feed was found . In the stomach contents of pigs fed fermented feed, a significant negative correlation was found between the concentration of the undissociated form of lactic acid and the numbers of Enterobacteriaceae . The numbers of Enterobacteriaceae in the contents of the stomach, ileum, cecum, colon, and rectum of pigs fed fermented feed were significantly lower compared with the contents of the stomach, ileum, caecum, colon, and rectum of pigs fed dry feed . The numbers of total lactobacilli were significantly higher in the stomach contents of pigs fed fermented feed and in the ileum contents of one pig group fed fermented feed compared with the contents of pigs fed dry feed . However, the influence of lactobacilli on numbers of Enterobacteriaceae could not be demonstrated . It was concluded that fermented feed influences the bacterial ecology of the gastrointestinal tract and reduces the levels of Enterobacteriaceae in the different parts of the gastrointestinal tract.

Electrophoresis, 2001 May, 22(9), 1686 - 96
Two-dimensional electrophoresis and peptide mass fingerprinting of bacterial outer membrane proteins; Molloy MP et al.; Many bacterial outer membrane proteins (OMPs) are missing from two-dimensional (2-D) gel proteome maps . Recently, we developed a technique for 2-D electrophoresis (2-DE) of Escherichia coli OMPs using alkaline pH incubation for isolation of OMPs, followed by improved solubilization conditions for array by 2-DE using immobilized pH gradients . In this report, we expanded our study, examining protein components from the outer membranes of two enteric bacteria, Salmonella typhimurium and Klebsiella pneumoniae (also known as Klebsiella aerogenes), as well as the unrelated, free-living alpha-proteobacteria Caulobacter crescentus . Patterns of OMPs expression appeared remarkably conserved between members of the Enterobacteriaceae, while C . crescentus was unique, displaying a greater number of clusters of higher-molecular-weight proteins (>80 kDa) . Peptide mass fingerprinting (PMF) was used for protein identification, and despite matching across-species boundaries, proved useful for first-pass protein assignment of enteric OMPs . In contrast, identification of C . crescentus OMPs was successful only when searching against its recently completed genome . For all three microorganisms examined, the majority of proteins identified on the 2-D gel appear localized to the outer membrane, a result consistent with our previous finding in Escherichia coli . In addition, we discuss some of the benefits and limitations of PMF in cross-species searching.

J Infect Dis, 2001 Jul 15, 184(2), 211 - 4 Epub 2001 Jun 18.
Enterobacter species in a pediatric hospital: horizontal transfer or selection in individual patients?
de Man P, van Der Veeke E, Leemreijze M, van Leeuwen W, Vos G, van Den Anker J, Verbrugh H, van Belkum A.
Enterobacter species were studied longitudinally in a children's hospital . In total, 287 Enterobacter isolates were obtained from 171 children in 15 different wards (from March 1995 through April 1997) . Strains were typed by random amplified polymorphic DNA and pulsed-field gel electrophoresis, which were concordant in outcome . In total, 97 DNA types and 199 colonization events were identified . A predominant clone was isolated 111 times from 62 children; another clone was isolated 19 times from 10 patients . These clones caused 36% of all colonizations . In 34% of the children, Enterobacter clones were found in 2-4 patients . The remaining colonizations were due to unique Enterobacter isolates . A large proportion of the Enterobacter strains was acquired through cross-transmission . This finding contrasts with the prevailing opinion that resistant Enterobacter strains are selected primarily from the patient's own gut flora.

J Ind Microbiol Biotechnol, 1999 Oct, 23(4-5), 314 - 319
Sphingomonas paucimobilis BPSI-3 mutant AN2 produces a red catabolite during biphenyl degradation; Davison AD et al.; The biphenyl degradation pathway of Sphingomonas paucimobilis BPSI-3 was investigated using a degradation-deficient mutant generated by 1-methyl-3-nitro-1-nitrosoguanidine (NTG) mutagenesis . The mutant, designated AN2, was confirmed as originating from BPSI-3 through the use of ERIC (Enterobacterial Repetitive Intergenic Consensus) PCR and by detection of the diagnostic pigment, nostoxanthin, in cellular methanol extracts . Mutant AN2 produced a yellow followed by red extracellular substance when grown in the presence of biphenyl . In the presence of 2,3-dihydroxybiphenyl, yellow followed by red then yellow compounds were formed over time . This colour change was consistent with the characteristics of a quinone, 1-phenyl-2,3-benzoquinone, which could arise from the oxidation of 2,3-dihydroxybiphenyl . A quinone was synthesised from 2,3-dihydroxybiphenyl and compared to the red compound produced by mutant AN2 . Gas chromatography-mass spectrophotometry (GC-MS) confirmed that a similar quinone (4,5-dimethoxy-3-phenyl-1,2-benzoquinone) compared to the structure of the proposed biogenic compound, had been formed . This compound was also found after GC-MS analysis of mutant AN2 culture extracts . Spectrophotometric analysis of the quinone synthesised and the red product produced revealed almost identical spectral profiles . A likely inference from this evidence is that the mutant AN2 is blocked, or its activity altered, in the first gene cluster, bphA to C, of the biphenyl degradation pathway.

Scand J Immunol, 2001 Jun, 53(6), 602 - 9
Elevated levels and different repertoire profile of colostral anti-LPS antibodies may have a significant role in compensating newborn immunity; Nagao AT et al.; A high prevalence of systemic infections caused by enterobacteria such as Escherichia coli is observed during the neonatal period . Lipopolysaccharide (LPS) is one of the major factors responsible for septic shock caused by these Gram-negative bacteria . We have recently demonstrated the presence of anti-LPS immunoglobulin (Ig)G antibodies in cord blood with a repertoire identical to that found in maternal serum . In the present study, we analyzed anti-LPS O111 antibody isotypes in maternal serum and colostrum from mothers and in cord serum from their respective full-term (n = 30) and preterm (n = 13) neonate infants . The main isotype found in serum samples from mothers of term infants was IgM (range between 28 and 54 mg/l), followed by IgA (1-2 mg/l) and IgG (2-3 mg/l) . The range of IgG antibody concentrations in cord blood was between 2 and 3 mg/l, as a result of placental transfer . A novel observation in our study was that the LPS bands recognized by colostral antibodies were completely different from those recognized by IgG in serum . Colostral IgA antibodies recognized several bands not bound by serum IgG antibodies from the respective maternal serum, independently of the antibody quantity . In addition, we verified the pattern of LPS recognition by serum IgA and colostral IgA antibodies was identical, what suggested that the antibody isotype found in serum could probably be derived from differentiated IgA-positive cells which were homing to the mucosa through the mucosal homing mechanism . Identical pattern of recognition was obtained comparing the IgA and IgM isotypes in colostrum . Slight differences in the pattern of recognition were found between colostral and serum IgM antibodies . The fact that colostral antibodies recognize much more bands than serum antibodies may be important for the host to mount an effective immune response in the intestinal lumen, in order to prevent excessive absorption of LPS, reducing possible systemic effects caused by the molecule.

Cell Microbiol, 2001 Jun, 3(6), 407 - 16
Unusual intracellular trafficking of Salmonella typhimurium in human melanoma cells; Martinez-Lorenzo MJ et al.; Salmonella spp . are enterobacteria capable of invading and replicating in both professional and non-professional phagocytes . Here, we investigate the fate of S . typhimurium in human melanoma MelJuSo cells . The bacterium entered MelJuSo cells by a trigger mechanism and resided within a unique organelle, the Salmonella-containing vacuole (SCV) . The SCV acquired early endosomal markers transiently and then underwent a series of membrane modifications . In HeLa cells, vacuole maturation is characterized by the simultaneous acquisition of the lysosomal membrane glycoproteins (Lgps) Lamp1, CD63 and vacuolar (v)-ATPase; in MelJuSo cells, however, acquisition of CD63 and v-ATPase preceded that of Lamp1 . A very striking event in MelJuSo cells was the arrest of bacterial septation starting from 8 h after infection . Bacteria nevertheless continued to elongate, remained morphologically intact and viable and were eventually exocytosed . This original feature was observed in several skin-related cells including melanocytes, suggesting that it may provide the basis for an efficient host defence mechanism against Salmonella infection.

Eur J Pediatr, 2001 Jun, 160(6), 385 - 91
Nosocomial necrotising enterocolitis outbreaks: epidemiology and control measures; Boccia D et al.; Necrotising enterocolitis (NEC) is one of the most serious gastrointestinal diseases among newborns and it mainly affects those in intensive care units . The aetiology of the disease has been reported to be multifactorial and both sporadic cases and nosocomial outbreaks have occurred . In this report, we review 17 epidemics of NEC reported in the literature between 1973 and 1999 . The number of confirmed cases ranged from 1 to 32 with an average of 10.5 confirmed cases . On average, 16.15% of cases required surgery (range 0-66.6%) . The average mortality rate was 6.25% (range 0-87.5%) . The mean age at disease onset was 9.5 days (range 6.6-29 days) . Most of the infants had low birth weight (median weight 1,395 g; range 1,112-2,788 g, calculated on the reported mean weights) . The main risk factors associated with NEC were: low birth weight, low gestational age, low Apgar score, perinatal complications, hyaline membrane disease, and umbilical catheterisation . The bacteria involved often included Enterobacteriaceae, particularly Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae type 3305573 . The causative role of Clostridia in NEC is controversial . With regard to viral agents, coronarovirus, rotavirus and enterovirus, such as echovirus type 22, were isolated during some of the epidemics . The recommended control measures for NEC epidemics are those used for epidemics of other orofaecally transmitted infections . CONCLUSION: Understanding the epidemiology of necrotising enterocolitis is fundamental if adequate preventive control measures are to be developed and applied.

Res Microbiol, 2001 Apr-May, 152(3-4), 303 - 10
ABC transporters catalyzing carbohydrate uptake; Schneider E; ATP binding cassette (ABC) transporters mediating the uptake of carbohydrates comprise two subfamilies (CUT1, CUT2) that differ with respect to the chemical nature of their substrates, subunit composition, and conserved sequence motifs . In this article, current knowledge of members of each family is summarized with special emphasis on the well-characterized transport systems for maltose/maltodextrin and ribose, respectively, of enterobacteria.

J Antimicrob Chemother, 2001 Jul, 48 Suppl 1, 29 - 42
The development of the BSAC standardized method of disc diffusion testing; Andrews JM; The BSAC Working Party on Susceptibility Testing has developed a standardized method of disc susceptibility testing that has been 'field tested' in 19 diagnostic laboratories in the UK and Ireland . The method employs semi-defined media, a semi-confluent inoculum and relates zones of inhibition with BSAC-specified MIC breakpoints to interpret susceptibility . The bacteria selected for the trial included clinical isolates and control strains from the ATCC and NCTC national collections . Organisms were chosen because they had known attributes, such as being fully susceptible or having a demonstrated mechanism of resistance . The results from this survey are very encouraging . With the commonly isolated Enterobacteriaceae, specifically Escherichia coli, Proteus mirabilis and Klebsiella spp., no major problems were observed except with gentamicin and cefuroxime . In the case of gentamicin, problems were associated with resistant strains of P . mirabilis, with MICs of 2 mg/L, being falsely reported as susceptible . For cefuroxime, it is not unexpected that results were unreliable, as the MIC distribution straddles the in vitro breakpoint concentration (following the results of this study the MIC and zone diameter breakpoints have been amended to improve reporting) . No major problems were encountered for Pseudomonas aeruginosa with the agents studied . The 'field survey' has shown that disc testing is unreliable for determining the susceptibility of coagulase-negative staphylococci to teicoplanin, and that the detection of glycopeptide resistance in enterococci is improved by incubation for a full 24 h . Inconsistencies observed with fastidious organisms were associated with incorrect inocula . Zone diameter data for the control strains studied provide information that can be utilized by diagnostic laboratories to monitor the daily performance of testing.

J Antimicrob Chemother, 2001 Jul, 48(1), 23 - 8
Comparative in vitro antimicrobial activity of a new carbapenem, E1010, and tentative disc diffusion test interpretative criteria; Fuchs PC et al.; The susceptibility of 705 bacterial isolates representing 46 different species to E1010 (ER-35786), imipenem, meropenem and cefepime was determined by the NCCLS broth microdilution test . The MIC(90)s for E1010 were < or =1.0 mg/L for Enterobacteriaceae, fastidious Gram-negative bacteria, streptococci and anaerobes . E1010 was two- to four-fold more active than imipenem and meropenem against Pseudomonas aeruginosa, and four-fold more active than the other carbapenems against methicillin-resistant Staphylococcus aureus . Vancomycin-resistant enterococci and most Enterococcus faecium were resistant to all four drugs tested . The NCCLS disc diffusion test was performed simultaneously on the non-fastidious organisms . Assuming the MIC breakpoints for E1010 will be the same as for the other carbapenems, the disc diffusion zone diameter breakpoints of imipenem and meropenem would also be applicable to E1010.

Avian Dis, 2001 Apr-Jun, 45(2), 486 - 91
Serologic reactions against Salmonella in samples from broiler parent stock with and without preceding colibacillosis: a case-control study; Gradel KO et al.; In the Danish Salmonella Control Program, eggs from broiler parent flocks are surveyed by serologic analysis every 4 wk for antibodies against Salmonella lipopolysaccharide O-antigens 1, 4, 5, 9, and 12 (Mix-enzyme-linked immunosorbent assay {ELISA}) and 6 and 7 (Infantis-ELISA) . The antibody response is measured in percentage optical density (OD%) of a strong positive reaction, and the cutoff value has been determined to be 40 OD% . Two or more reactors above 40 OD% will place the parent flock under suspicion . There has been concern about possible cross-reactions between Salmonella spp . and other Enterobacteriaceae, e.g., Escherichia coli, because a high specificity of a Salmonella antibody test is desirable . Moreover, false-positive Salmonella results have economic consequences and impede planning the production . A case-control study based on cases of clinical E . coli infections (colibacillosis) from two Danish hatcheries, supplying about 62% of the Danish broiler production, is described . In order to eliminate a possible bias from age and season, the controls were matched on age of the birds and on time of submitting the samples . This study shows that flocks with preceding colibacillosis did not have higher salmonella reactions than matched flocks without a preceding colibacillosis . This observation was confirmed in longitudinal studies.

Avian Dis, 2001 Apr-Jun, 45(2), 447 - 51
Bacterial flora of the conjunctiva and nasal cavity in normal and diseased captive bustards; Silvanose CD et al.; A survey was carried out to describe the normal aerobic bacterial flora of the conjunctiva and nasal cavity of captive houbara bustards (Chlamydotis undulata), kori bustards (Ardeotis kori), and white-bellied bustards (Eupodotis senegalensis) maintained at the National Avian Research Center, Abu Dhabi, United Arab Emirates . A total of 58 samples were examined from the nasal cavity and 55 samples from the conjunctiva of healthy bustards . There was no bacterial growth in 45% of conjunctival samples . Bacteria isolated from the conjunctiva of healthy birds included Micrococcus spp., Staphylococcus auricularis, Staphylococcus xylosus, Staphylococcus capitis, Staphylococcus warneri, Bacillus spp., and Enterobacter amigenus . Bacteria isolated from the nasal cavity of healthy birds included Bacillus spp., Micrococcus spp., S . auricularis, S . xylosus, Staphylococcus simulans, Staphylococcus saprophyticus, Staphylococcus hyicus, Staphylococcus cohnii, Staphylococcus sciuri, Aerococcus spp., and Providencia rettgeri . These findings were compared with bacterial isolates from bustards with clinical signs of ocular or upper respiratory tract diseases . Mycoplasma spp., Pseudomonas aeruginosa, Pseudomonas stutzeri, Proteus mirabilis, Escherichia coli, Klebsiella spp., Aeromonas hydrophila, and Staphylococcus aureus were the pathogenic bacteria isolated from the conjunctiva of 34.3% bustards with ocular discharges . Mycoplasma spp., P . aeruginosa, Pseudomonas spp., P . mirabilis, E . coli, Klebsiella pneumoniae, and S . aureus were the pathogenic bacteria isolated from the nasal cavity of 74% bustards with upper respiratory tract diseases.

Southeast Asian J Trop Med Public Health, 2000 Dec, 31(4), 668 - 73
Detection and molecular characterization of Vibrio vulnificus from coastal waters of Malaysia; Radu S et al.; A total of 57 Vibrio vulnificus isolates from coastal water were characterized for their antimicrobial resistance, plasmid profiles and were typed by the PCR-based techniques: a random amplification of polymorphic DNA (RAPD) method and the enterobacterial repetitive intergenic consensus sequence (ERIC) method . All isolates were susceptible to chloramphenicol, nalidixic acid, tetracycline and trimethoprim-sulfamethoxazole . Fifty-one isolates were resistant to one or more of the other antibiotics tested . Plasmid analysis indicated that only 18 isolates carried small plasmids of 1.6 to 16 megadaltons . Analysis of the RAPD and ERIC DNA fingerprints of the V . vulnificus isolates with Gel Compare and cluster analysis software revealed significant genetic heterogeneity among these isolates . The combination of RAPD and ERIC analysis allowed us to distinguish all isolates . Thus, the combination of the two techniques is recommended for epidemiological investigation.

Lett Appl Microbiol, 2001 Jun, 32(6), 424 - 7
recA genotyping of Salmonella enteritidis phage type 4 isolates by restriction fragment length polymorphism analysis; Matsui T et al.; AIMS: To subtype Salmonella enteritidis phage type 4 isolates by using recA genotyping . METHODS AND RESULTS: Random amplified polymorphic DNA analysis using a primer ERIC2 of 76 isolates of Salmonella enteritidis phage type 4 obtained in Northern Ireland in 1998 and in 1999 demonstrated the presence of five genotypes . Restriction fragment length polymorphism analysis, using a degenerate primer pair designed to amplify a segment (about 640 bp in length) of the recA gene from several members of the Enterobacteriaceae with restriction enzymes, HhaI and Sau3AI, showed that the resulting fragments could differentiate the isolates into three groups, respectively . CONCLUSION: recA gene amplification and HhaI and Sau3AI restriction digestion was demonstrated to increase the differentiating power between isolates of Salmonella enteritidis phage type 4 by combining the patterns of the random amplified polymorphic DNA analysis procedure using a primer ERIC2 . Significance and Impact of the Study: A novel restriction fragment length polymorphism assay for isolates of Salmonella enteritidis phage type 4, based on the amplification of the recA gene was attained and its comparison and its combination with random amplified polymorphic DNA analysis was provided.

J Appl Microbiol, 2001 Jun, 90(6), 850 - 8
Comparison of methods for determining the numbers and species distribution of coliform bacteria in well water samples; Niemi RM et al.; AIMS: Enumeration of coliform bacteria and Escherichia coli is the most widely used method in the estimation of hygienic quality of drinking water . The yield of target bacteria and the species composition of different populations of coliform bacteria may depend on the method.Three methods were compared . METHODS AND RESULTS: Three membrane filtration methods were used for the enumeration of coliform bacteria in shallow well waters . The yield of confirmed coliform bacteria was highest on Differential Coliform agar, followed by LES Endo agar . Differential Coliform agar had the highest proportion of typical colonies, of which 74% were confirmed as belonging to the Enterobacteriaceae . Of the typical colonies on Lactose Tergitol 7 TTC agar, 75% were confirmed as Enterobacteriaceae, whereas 92% of typical colonies on LES Endo agar belonged to the Enterobacteriaceae . LES Endo agar yielded many Serratia strains, Lactose Tergitol 7 TTC agar yielded numerous strains of Rahnella aquatilis and Enterobacter, whereas Differential Coliform agar yielded the widest range of species . CONCLUSION: The yield of coliform bacteria varied between methods . Each method compared had a characteristic species distribution of target bacteria and a typical level of interference of non-target bacteria . Identification with routine physiological tests to distinct species was hampered by the slight differences between species . High yield and sufficient selectivity are difficult to achieve simultaneously, especially if the target group is diverse . SIGNIFICANCE AND IMPACT OF THE STUDY: The results showed that several aspects of method performance should be considered, and that the target group must be distinctly defined to enable method comparisons.

Int J Syst Evol Microbiol, 2001 May, 51(Pt 3), 925 - 32
Phylogenetic analyses of Klebsiella species delineate Klebsiella and Raoultella gen . nov., with description of Raoultella ornithinolytica comb . nov., Raoultella terrigena comb . nov . and Raoultella planticola comb . nov; Drancourt M et al.; The phylogenetic relationships of the type strains of 9 Klebsiella species and 20 species from 11 genera of the family Enterobacteriaceae were investigated by performing a comparative analysis of the sequences of the 16S rRNA and rpoB genes . The sequence data were phylogenetically analysed by the neighbourjoining and parsimony methods . The phylogenetic inference of the sequence comparison confirmed that the genus Klebsiella is heterogeneous and composed of species which form three clusters that also included members of other genera, including Enterobacter aerogenes, Erwinia clusters I and II and Tatumella . Cluster I contained the type strains of Klebsiella pneumoniae subsp . pneumoniae, Klebsiella pneumoniae subsp . rhinoscleromatis and Klebsiella pneumoniae subsp . ozaenae . Cluster II contained Klebsiella ornithinolytica, Klebsiella planticola, Klebsiella trevisanii and Klebsiella terrigena, organisms characterized by growth at 10 degrees C and utilization of L-sorbose as carbon source . Cluster III contained Klebsiella oxytoca . The data from the sequence analyses along with previously reported biochemical and DNA-DNA hybridization data support the division of the genus Klebsiella into two genera and one genogroup . The name Raoultella is proposed as a genus name for species of cluster II and emended definitions of Klebsiella species are proposed.

C R Acad Sci III, 2001 May, 324(5), 489 - 94
A putative insect intracellular endosymbiont stem clade, within the Enterobacteriaceae, infered from phylogenetic analysis based on a heterogeneous model of DNA evolution; Charles H et al.; Insect intracellular symbiotic bacteria (intracellular endosymbionts, or endocytobionts) were positioned within the gamma 3-Proteobacteria using a non-homogeneous model of DNA evolution, allowing for rate variability among sites, for GC content heterogeneity among sequences, and applied to a maximum likelihood framework . Most of them were found to be closely related within the Enterobacteriaceae family, located between Proteus and Yersinia . These results suggest that such a bacterial group might possess several traits allowing for insect infection and the stable establishment of symbiotic relationships and that this could represent a stem clade for numerous insect endocytobionts . Based on the estimations of the equilibrium GC content and branch lengths in the phylogenetic tree, we have made comparisons of the relative ages of these different symbioses.

Proc Natl Acad Sci U S A, 2001 Jun 19, 98(13), 7546 - 51 Epub 2001 Jun 12.
A novel application of gene arrays: Escherichia coli array provides insight into the biology of the obligate endosymbiont of tsetse flies; Akman L et al.; Symbiotic associations with microorganisms are pivotal in many insects . Yet, the functional roles of obligate symbionts have been difficult to study because it has not been possible to cultivate these organisms in vitro . The medically important tsetse fly (Diptera: Glossinidae) relies on its obligate endosymbiont, Wigglesworthia glossinidia, a member of the Enterobacteriaceae, closely related to Escherichia coli, for fertility and possibly nutrition . We show here that the intracellular Wigglesworthia has a reduced genome size smaller than 770 kb . In an attempt to understand the composition of its genome, we used the gene arrays developed for E . coli . We were able to identify 650 orthologous genes in Wigglesworthia corresponding to approximately 85% of its genome . The arrays were also applied for expression analysis using Wigglesworthia cDNA and 61 gene products were detected, presumably coding for some of its most abundant products . Overall, genes involved in cell processes, DNA replication, transcription, and translation were found largely retained in the small genome of Wigglesworthia . In addition, genes coding for transport proteins, chaperones, biosynthesis of cofactors, and some amino acids were found to comprise a significant portion, suggesting an important role for these proteins in its symbiotic life . Based on its expression profile, we predict that Wigglesworthia may be a facultative anaerobic organism that utilizes ammonia as its major source of nitrogen . We present an application of E . coli gene arrays to obtain broad genome information for a closely related organism in the absence of complete genome sequence data.

Diagn Microbiol Infect Dis, 2001 Apr, 39(4), 251 - 6
Effect of removal of duplicate isolates on cumulative susceptibility reports; White RL et al.; The objective of our study is to assess the impact of different methods of duplicate isolate removal on cumulative susceptibility reports.Over a 1-year period, we studied the effect of 3 methods of duplicate isolate removal on the cumulative percentage susceptibility of 9 Gram-negative bacilli to 15 antimicrobials . Raw data from which no duplicate isolates were removed (NR) were generated by the Sensititre breakpoint susceptibility testing system . D3 and D7 were methods of duplicate isolate removal defined as follows: same patient, bacterial species, irrespective of susceptibility within either three (D3) or seven (D7) calendar days of the date of the previous culture . The third method evaluated was an algorithm utilized by Cerner, a laboratory management program that defines duplicate isolates as follows: same patient, bacterial species, and NCCLS susceptibility category to an individual antimicrobial . Differences in percentage susceptibility between the three methods of duplicate isolate removal and NR were assessed.The number of isolates studied ranged from 80 (E . aerogenes) to 681 (P . aeruginosa) . Of the methods of duplicate isolate removal, the highest percentage susceptibility occurred most frequently with Cerner followed by D7 and D3 . Differences in percentage susceptibility between methods of removal and NR ranged from -11 to 25%, -5 to 8%, and -3 to 10%, with Cerner, D3, and D7, respectively . The percentage susceptibility was at least 5% higher than NR with a method of removal for 15 individual organism/antimicrobial combinations in which susceptibility was > or = 70% by at least one of the methods . These occurred most frequently with Enterobacter species and Cerner . Although there is no consensus on the ideal method of duplicate isolate removal, one should be cognizant that these manipulations may produce different cumulative susceptibility reports.

Diagn Microbiol Infect Dis, 2001 Apr, 39(4), 237 - 43
Can antimicrobial susceptibility testing results for ciprofloxacin or levofloxacin predict susceptibility to a newer fluoroquinolone, gatifloxacin?: Report from The SENTRY Antimicrobial Surveillance Program (1997-99); Jones RN et al.; A serious problem confronting clinical laboratories and hospital formulary practices is the delayed availability of approved, commercially prepared susceptibility test reagents for newer antimicrobials . A current example is gatifloxacin, a new 8-methoxy fluoroquinolone with expanded potency against many Gram-positive pathogens . This study addresses the use of "surrogate marker" fluoroquinolones to predict susceptibility for gatifloxacin . Reference broth microdilution MIC results for 29,632 strains isolated in United States medical centers (SENTRY Antimicrobial Surveillance Program, 1997-99) were used: staphylococci (9,940 strains), enterococci (2,570), Streptococcus pneumoniae (3,784), Enterobacteriaceae (10,670) and Pseudomonas aeruginosa (2,668) . Gatifloxacin interpretation categories were compared to those of ciprofloxacin and levofloxacin by regression statistics and error rate bounding analyses . For the Enterobacteriaceae, the absolute categorical agreement was 97.9 to 98.7% (false-susceptible or very-major error {VME}, 0.03%-0.1%) for comparisons of both ciprofloxacin and levofloxacin with gatifloxacin . P . aeruginosa testing was more problematic (higher minor error rates), but acceptable at 0.6% to 1.1% VME and a 85.7% to 89.9% overall agreement . Ciprofloxacin results used to predict gatifloxacin in Gram-positive species was almost without VME (0.0%-0.2%) because gatifloxacin was significantly superior against these species, especially for S . pneumoniae, where gatifloxacin (MIC(90,) 0.5 microg/ml) was fourfold more potent than levofloxacin (MIC(90,) 2 microg/ml) . The preferred gatifloxacin predictor drug was ciprofloxacin for all species except S . pneumoniae and P . aeruginosa, where levofloxacin results had a slightly greater predictive value . Susceptibility testing results for selected currently available fluoroquinolones can be used to predict susceptibility to gatifloxacin with high confidence . Many Gram-positive cocci, however, will be categorized as false-resistant by this interim method since gatifloxacin has a 11% to 34% wider spectrum of activity compared to ciprofloxacin when testing staphylococci and enterococci . Clinical laboratories can reliably use these suggested "surrogate markers" until reliable tests for gatifloxacin become available.

P N G Med J, 2000 Mar-Jun, 43(1-2), 82 - 90
Antibiotic-resistant bacterial sepsis in Papua New Guinea; Duke T; Infections due to antibiotic-resistant bacteria, especially gram-negative bacteria, are a common cause of child mortality in Papua New Guinea . Antibiotic-resistant bacteria include the enteric gram-negative bacilli, especially Escherichia coli, Klebsiella and Enterobacter, and Haemophilus influenzae type b, a major respiratory tract pathogen and cause of meningitis . Among these bacteria there is now high-level resistance to standard antibiotics, including chloramphenicol, amoxycillin and cotrimoxazole . Reasons behind the increase in antibiotic-resistant bacterial infections are the widespread unregulated use of antibiotics and the very large burden of bacterial infections . Risk factors for development of resistant enteric gram-negative infections include village births, prolonged hospital stay, kwashiorkor in adopted children and previous treatment with broad-spectrum antibiotics . Cost-effective strategies to combat these pathogens will need to be broad and must focus on reducing the use of antibiotics for trivial illnesses, reducing the need to use antibiotics and reducing the risk factors for resistant bacterial sepsis . There must be stricter regulation of commercial pharmacies, education of health workers on how to avoid inappropriate antibiotic prescribing, a focus on the prevention of pneumonia by immunization with new vaccines, improvements in the quality and uptake of formal maternal care services and public health measures within villages . In addition there is a need for better surveillance for antibiotic-resistant bacteria within hospitals; this will require substantial improvements in laboratory facilities and carefully planned research collaboration . A national committee should be established to advise on these matters and coordinate interventions.

Adv Microb Physiol, 2001, 44, 215 - 57
Extracellular sensing components and extracellular induction component alarmones give early warning against stress in Escherichia coli; Rowbury RJ; The work reported here follows from the proposal that, for efficient induction of numerous extracellular stress responses, cultures contain extracellular stress-sensing molecules, termed extracellular sensing components (ESCs) . These are directly converted to extracellular induction components (EICs) by stresses, thus providing an early warning system against stress, with very rapid responses occurring on exposure to increasing levels of stress . Although some stress responses appear to involve activation of intracellular sensors, the proposed ESCs and EICs function for many stress tolerance and sensitization responses and for several cross-tolerance and cross-sensitization responses . Because EICs can induce responses in unstressed cells, and because they are small molecules that can diffuse away from the site of formation, they can be considered to be 'alarmones', both warning unstressed organisms of future stress and preparing both stressed and unstressed ones to resist it . Therefore, EICs produced by one group of organisms could affect another group i.e . there could be 'cross-talk' (cell-to-cell communication) with other organisms in an area, to which the EICs diffuse, that has not yet faced the stress . In particular, stimuli that switch on acid tolerance, alkali tolerance, pH sensitization responses and alkylhydroperoxide tolerance are detected by ESCs; these molecules can give rise to EICs in the presence of the stress without organisms needing to be present . Not only does the ESC-EIC interconversion allow rapid switching on of responses, but for some responses it also allows rapid switching off . For some ESCs, the sensor can be modified by the culture conditions, modification leading to altered responsiveness to stress; such sensor changes appear to have evolved to allow the most efficient responses to stress to occur, under defined sets of conditions . In addition, the receptors on the organisms that interact with EICs are modified by culture conditions, so that extracellular components that function as ESCs for some cultures can act as EICs for others . In view of their role in early warning of stress, EICs and ESCs are likely to have important functions in the natural environment, especially in natural waters, in foods and food preparation and production, in hospital, domestic and commercial locations, and in the animal and human body . Findings of major importance relate to the extreme stress tolerance of some EICs . For example, because the acid-tolerance EIC formed at pH 5.0 is a heat-resistant molecule, heat-killed suspensions of acid-tolerant cultures can confer acid tolerance on living E . coli; cultures killed by extreme acidity and alkalinity and by exposure to high levels of UV irradiation or novobiocin are also able to confer acid tolerance on living E . coli . Extracellular components that inhibit induction of stress responses also occur in enterobacteria, since it has been found that AMP and HCO3-, which inhibit acid-tolerance induction, do so by forming extracellular agents that block the functioning of EICs . Similar agents to the above EICs and ESCs may occur in other non-stress-related processes . Systems using these extracellular components are quite distinct in their properties from quorum-sensing systems in Gram-negative bacteria and from those systems that use small peptides in intercellular communication and which induce virulence-related enzyme synthesis in Staphylococcus aureus and competence in streptococci and bacilli . Additionally, probably because the ESCs have evolved to become modified by cultural conditions, the components in the stress-related systems, although relatively small proteins, are much larger than the extracellular components used in the quorum-sensing processes and related systems . It is possible that the extracellular 'protectants' of Nikolaev, which protect E . coli from stress, act similarly to the EICs described here, e.g . by inducing stress tolerance . The antimutagenic factor of Vorobjeva may act similarly, although there is no evidence, so far, to suggest that it acts by inducing tolerance to mutagens.

Int J Med Microbiol, 2001 Apr, 291(1), 15 - 20
Distribution and expression of the astA gene (EAST1 toxin) in Escherichia coli and Salmonella; Paiva de Sousa C et al.; The distribution and expression of the astA gene (EAST1 toxin) among 358 strains of Enterobacteriaceae were studied . The gene was found in 32.6% and 11.9% of Escherichia coli and Salmonella strains, respectively . The majority of E . coli EAST1-positive strains were found among EHEC (88.0%), EAggEC (86.6%), and A-EPEC (58.3%) . The gene was present in 16.6% of E . coli strains without known virulence genes . There was no significant variation among the different serotypes of E . coli tested regarding the presence of the gene . For EPEC, 13.7% of the tested strains were astA-positive . Among atypical EPEC (eae+, bfp-, EAF-) and (eae+, bfp+, EAF-) 46.2 and 72.7%, respectively, were positive . The majority of the A-EPEC (87%) and EaggEC (83%) strains expressed the EAST-1 toxin as judged from Ussing chamber experiments . Of 32 EIEC strains studied, 2 possessed and expressed the gene as determined in Ussing chamber experiments . Among the Salmonella strains studied, five strains isolated from food were positive for astA and one strain of S . agona showed biological activity in Ussing chamber experiments.

Syst Appl Microbiol, 2001 Apr, 24(1), 54 - 62
Diversity of polyamine patterns in soft rot pathogens and other plant-associated members of the Enterobacteriaceae; Zherebilo OE et al.; Polyamine profiles of 91 pectolytic and other plant-associated strains from 30 taxa of the Enterobacteriaceae were obtained by gradient high performance liquid chromatography (HPLC) . Pectobacterium carotovorum, basonym Erwinia carotovora, contained a high amount of putrescine and less diaminopropane . Diaminopropane was absent in Pectobacterium chrysanthemi, basonym E . chrysanthemi, whereas cadaverine was present in addition to the major compound putrescine . This chemotaxonomic difference reflects the deepest phylogenetic branching point within the recently emended genus Pectobacterium which lies between the two species P . carotovorum and P . chrysanthemi . Both important soft rot pathogens are easily distinguishable from each other and from the type species of the genus Erwinia as diaminopropane is the only major polyamine compound in E . amylovora . Chemotaxonomic heterogeneity is also emerging with respect to DYE's Amylovora group proposed in an early phytopathological concept.

J Food Prot, 2001 Jun, 64(6), 845 - 9
Glove barriers to bacterial cross-contamination between hands to food; Montville R et al.; Human hands are an important source of microbial contamination of foods . However, published data on the effectiveness of handwashing and glove use in a foodservice setting are limited . Bacterial transfer through foodservice quality gloves was quantified using nalidixic acid-resistant Enterobacter aerogenes (a nonpathogenic surrogate with attachment characteristics similar to Salmonella) . Five transfer rates were determined: chicken to bare hand, chicken to hand through gloves, bare hand to lettuce, hand to lettuce through gloves (with low inoculum on hands), and hand to lettuce through gloves (with high inoculum on hands) . At least 30 observations were made for each percent transfer rate using 30 individual volunteers . The logarithm of percent transfer data were then fit to distributions: chicken to bare hand, normal (0.71, 0.42); chicken to hand through gloves, gamma (5.91, 0.40, -5.00); bare hand to lettuce, logistic (1.16, 0.30); hand to lettuce through gloves (low inoculum), normal (0.35, 0.88); hand to lettuce through gloves (high inoculum), normal (-2.52, 0.61) . A 0.01% transfer was observed from food to hands and from hands to food when subjects wore gloves and a 10% transfer was observed without a glove barrier . These results indicate that gloves are permeable to bacteria although transfer from hands to food through a glove barrier was less than without a glove barrier . Our results indicate that gloves may reduce both bacterial transfer from food to the hands of foodservice workers and in subsequent transfer from hands back to food.

Infect Immun, 2001 Jul, 69(7), 4458 - 64
Analysis of the capsule biosynthetic locus of Mannheimia (Pasteurella) haemolytica A1 and proposal of a nomenclature system; Lo RY et al.; A 16-kbp DNA region that contains genes involved in the biosynthesis of the capsule of Mannheimia (Pasteurella) haemolytica A1 has been characterized . The gene cluster can be divided into three regions like those of the typical group II capsule biosynthetic clusters in gram-negative bacteria . Region 1 contains four genes (wzt, wzm, wzf, and wza) which code for an ATP-binding cassette transport apparatus for the secretion of the capsule materials across the membranes . The M . haemolytica A1 wzt and wzm genes were able to complement Escherichia coli kpsT and kpsM mutants, respectively . Further, the ATP binding activity of Wzt was demonstrated by its affinity for ATP-agarose, and the lipoprotein nature of Wza was supported by {(3)H}palmitate labeling . Region 2 contains six genes; four genes (orf1/2/3/4) code for unique functions for which no homologues have been identified to date . The remaining two genes (nmaA and nmaB) code for homologues of UDP-N-acetylglucosamine-2-epimerase and UDP-N-acetylmannosamine dehydrogenase, respectively . These two proteins are highly homologous to the E . coli WecB and WecC proteins (formerly known as RffE and RffD), which are involved in the biosynthesis of enterobacterial common antigen (ECA) . Complementation of an E . coli rffE/D mutant with the M . haemolytica A1 nmaA/B genes resulted in the restoration of ECA biosynthesis . Region 3 contains two genes (wbrA and wbrB) which are suggested to be involved in the phospholipid modification of capsular materials.

Infect Immun, 2001 Jul, 69(7), 4447 - 57
Novel type of fimbriae encoded by the large plasmid of sorbitol-fermenting enterohemorrhagic Escherichia coli O157:H(-); Brunder W et al.; Sorbitol-fermenting (SF) enterohemorrhagic Escherichia coli (EHEC) O157:H(-) have emerged as important causes of diarrheal diseases and the hemolytic-uremic syndrome in Germany . In this study, we characterized a 32-kb fragment of the plasmid of SF EHEC O157:H(-), pSFO157, which differs markedly from plasmid pO157 of classical non-sorbitol-fermenting EHEC O157:H7 . We found a cluster of six genes, termed sfpA, sfpH, sfpC, sfpD, sfpJ, and sfpG, which mediate mannose-resistant hemagglutination and the expression of fimbriae . sfp genes are similar to the pap genes, encoding P-fimbriae of uropathogenic E . coli, but the sfp cluster lacks homologues of genes encoding subunits of a tip fibrillum as well as regulatory genes . The major pilin, SfpA, despite its similarity to PapA, does not cluster together with known PapA alleles in a phylogenetic tree but is structurally related to the PmpA pilin of Proteus mirabilis . The putative adhesin gene sfpG, responsible for the hemagglutination phenotype, shows significant homology neither to papG nor to other known sequences . Sfp fimbriae are 3 to 5 nm in diameter, in contrast to P-fimbriae, which are 7 nm in diameter . PCR analyses showed that the sfp gene cluster is a characteristic of SF EHEC O157:H(-) strains and is not present in other EHEC isolates, diarrheagenic E . coli, or other Enterobacteriaceae . The sfp gene cluster is flanked by two blocks of insertion sequences and an origin of plasmid replication, indicating that horizontal gene transfer may have contributed to the presence of Sfp fimbriae in SF EHEC O157:H(-).

Int J Antimicrob Agents, 2001 Jun, 17(6), 521 - 4
Another look at differences in the susceptibility of Escherichia coli and Klebsiella pneumoniae to cephalothin and cefazolin; Yeh LL et al.; The significance of in vitro susceptibility tests on Enterobacteriaceae to cephalothin and cefazolin has not been exactly defined in the guidelines of the National Committee for Clinical Laboratory Standards . In the hope of clarifying this confusion, we provide additional information from an ancillary study of the Taiwan Surveillance of Antimicrobial Resistance 1998 (TSAR I) . There were 505 Escherichia coli and 227 Klebsiella pneumoniae isolates susceptible to cephalothin, reported by 42 participating hospitals . The susceptibility of these isolates were re-tested at the Microbial Infections Reference Laboratory using cefazolin, with the result that 72% of the 252 cephalothin-resistant E . coli isolates and 24% of the 41 cephalothin-resistant K . pneumoniae isolates were found to be susceptible to cefazolin . We further surveyed the availability of cephalothin and cefazolin in Pharmacy Departments; all of the TSAR I hospitals had cefazolin available in their pharmacies . The resistance rate of E . coli was significantly lower for 12 hospitals that had cefazolin in both pharmacy and laboratory compared with 11 hospitals that had cefazolin available in pharmacy but cephalothin in laboratory . In addition, for all the hospitals that had cephalothin available for clinical use, the resistance rate was twice as low in two hospitals reporting cefazolin susceptibility as in the seven hospitals reporting cephalothin susceptibility . Our findings suggest that inappropriate selection of cephalothin and cefazolin for susceptibility testing contribute to inaccurate indications of in vivo activity for first generation cephalosporins in the treatment of E . coli infections.

Int J Antimicrob Agents, 2001 Jun, 17(6), 477 - 81
Nosocomial bloodstream infections in a Turkish university hospital: study of Gram-negative bacilli and their sensitivity patterns; Koseoglu O et al.; Treatment of nosocomial bacteraemia is usually governed by the surveillance results of the particular unit . Such results are especially important when antimicrobial resistance rates are high . Multiresistant isolates including Gram-negatives producing extended-spectrum beta-lactamases have been frequently reported in tertiary care units in Turkey . In this study, antimicrobial susceptibilities of Gram-negative blood isolates (n=348) were determined by microbroth dilution tests . The results showed carbapenems (meropenem and imipenem) to be uniformly more potent in vitro than any other drug against the Enterobacteriaceae . Quinolone antibiotics were more active in vitro than aminoglycosides against a range of bacteria . Gram-negative bloodstream isolates were highly resistant to many antimicrobial agents in the hospital . In order to prevent hospital infection and antimicrobial resistance, surveillance of aetiological agents must be performed regularly.

Cad Saude Publica, 2001 May-Jun, 17(3), 713 - 7
{Antimicrobial resistance of coliform isolates from expressed human milk}; Novak FR et al.; The dispersion of potentially pathogenic, antibiotic-resistant microorganisms via expressed human milk can be considered a risk factor . The aim of this study was to contribute to a better understanding of coliform isolates from expressed human milk and their antimicrobial resistance profiles . The sampling scheme followed a totally randomized design, using 837 samples of expressed human milk . Of these, 71 (8.48%) were identified as contaminated with total coliforms, although in none of the samples did the population exceed 1.0x10(3) MPN/ml . Most of the microorganisms isolated (91.6%) belonged to only two species, Enterobacter cloacae and Klebsiella pneumoniae, which when subjected to antibiograms, revealed that several strains showed prior resistance to some of the antimicrobials tested . Coliforms may grow in expressed human milk if it is improperly stored, depleting protection factors and reducing the milk's nutritional value.

J Am Vet Med Assoc, 2001 May 15, 218(10), 1608 - 10
Bacterial isolates from blood and their susceptibility patterns in critically ill foals: 543 cases (1991-1998); Marsh PS et al.; OBJECTIVE: To assess microorganisms isolated from blood specimens obtained from critically ill neonatal foals and to evaluate their antimicrobial susceptibility patterns . DESIGN: Retrospective study . ANIMALS: 543 neonatal foals . PROCEDURE: Medical records of foals that were < 1 month old and were admitted to a referral neonatal intensive care unit were reviewed for results of bacteriologic culture of blood and antimicrobial susceptibility patterns . RESULTS: At least 1 microorganism was isolated from 155 of 543 (28.5%) foals . Escherichia coli was the most commonly isolated bacterium . A single gram-positive organism was detected in 49 foals . Although 90% of the E coli isolates were susceptible to amikacin, some gram-negative and gram-positive organisms had resistance against multiple antimicrobials . CONCLUSIONS AND CLINICAL RELEVANCE: Gram-negative bacteria remain the most common isolates from blood of neonatal foals; however, gram-positive organisms were also found, and with greater prevalence than reported elsewhere . Susceptibility patterns may vary, and resistance to multiple antimicrobials may develop . This is especially true for organisms such as Enterobacter spp and Enterococcus spp . Prudent empirical treatment for neonatal sepsis should include broad-spectrum antimicrobials.

Paediatr Drugs, 2001, 3(5), 365 - 77
Fluoroquinolones in paediatrics; Gendrel D et al.; The fluoroquinolones are an important group of antibiotics, which are widely used in adult patients because of their high penetration in tissues and bactericidal activity . However, they are not licensed for paediatric use (except the limited indication of Pseudomonas infection in cystic fibrosis) because of their potential to cause joint toxicity (observed in experiments using juvenile animal models) . In recent years, there has been a change in the susceptibility of pathogens to widely used antibiotics; however, many of these pathogens remain sensitive to the fluoroquinolones (agents which can often be administered orally to treat severe infections) . Fluoroquinolones have a number of potential indications in children: cystic fibrosis, intestinal infections due to resistant strains of Salmonella spp . and Shigella spp., severe infections due to Enterobacteriaceae (including the neonatal period), complicated urinary tract infections, the immunocompromised host, and some mycobacterial infections . The third generation fluoroquinolones have improved activity against Gram-positive bacteria and could be useful in respiratory tract, and ear, nose and throat infections in adult patients . Their potential role in routine use for paediatric patients will remain limited because of potential joint complications and the availability of other treatment options . However, available clinical data does indicate that the incidence of arthrotoxicity in children treated with ciprofloxacin appears to be the same as that in adult patients . The use of other fluoroquinolones is too rare to obtain meaningful information on their toxicity in children . For future fluoroquinolones, pneumococcal meningitis will probably be a potential indication . Despite their important activity, fluoroquinolones remain a second-line treatment in children, for use following the failure of a well established antibiotic treatment, to avoid potential adverse effects and the emergence of resistant strains.

Antonie Van Leeuwenhoek, 2001 Jan, 79(1), 89 - 96
Microbiology and physiology of Cachaça (Aguardente) fermentations; Schwan RF et al.; Cachaca (aguardente) is a rum-style spirit made from sugar cane juice by artisanal methods in Brazil . A study was made of the production, biochemistry and microbiology of the process in fifteen distilleries in Sul de Minas . Identification of 443 yeasts showed Saccharomyces cerevisiae to be the predominant yeast but Rhodotorula glutinis and Candida maltosa were predominant in three cases . Bacterial infection is a potential problem, particularly in older wooden vats, when the ratio of yeasts:bacteria can be 10:1 or less . A study of daily batch fermentations in one distillery over one season in which 739 yeasts were identified revealed that S . cerevisiae was the predominant yeast . Six other yeast species showed a daily succession: Kluyveromyces marxianus, Pichia heimii and Hanseniaspora uvarum were present only at the beginning, Pichia subpelliculosa and Debaryomyces hansenii were detected from mid to the end of fermentation, and Pichia methanolica appeared briefly after the cessation of fermentation . Despite a steady influx of yeasts from nature, the species population in the fermenter was stable for at least four months suggesting strong physiological and ecological pressure for its maintenance . Cell densities during the fermentation were: yeasts - 4 x 108/ml; lactic acid bacteria -4 x 10(5)/ml; and bacilli - 5 x 10(4)/ml . Some acetic acid bacteria and enterobacteriaceae appeared at the end . Sucrose was immediately hydrolysed to fructose and glucose . The main fermentation was complete after 12 hours but not all fructose was utilised when harvesting after 24 hours.

Microb Ecol, 2001 Apr, 41(3), 281 - 288
Expression of the ACC Deaminase Gene fromEnterobacter cloacae UW4 in Azospirillum brasilense; Holguin G et al.; The ACC deaminase structural gene (acdS) from Enterobacter cloacae UW4 was cloned in the broad host range plasmid pRK415 under the control of the lac promoter and transferred into Azospirillum brasilense Cd and Sp245 . A . brasilenseCd and Sp245 transformants showed high ACC deaminase activity, similar to that observed in Enterobacter cloacae UW4 . The expression of ACC deaminase improved the existing growth promoting activity of Azospirillum . The roots of tomato and canola seedlings were significantly longer in plants inoculated with A . brasilense Cd transformants than those in plants inoculated with the nontransformed strains of the same bacterium . In the case of wheat seedlings, inoculation with A . brasilense Cd transformants did not promote root growth . The difference in plant response (canola and tomato versus wheat) is attributed to the greater sensitivity of canola and tomato plants to ethylene as compared to wheat plants.

Am J Infect Control, 2001 Jun, 29(3), 162 - 7
Clinical assay of N-duopropenide alcohol solution on hand application in newborn and pediatric intensive care units: control of an outbreak of multiresistant Klebsiella pneumoniae in a newborn intensive care unit with this measure; Herruzo-Cabrera R et al.; Outbreaks of gram-negative colonization (generally by antibiotic-resistant enterobacteria) are common in newborn intensive care units (NICUs), and control methods are not always effective . We studied the effectiveness of an alcohol solution of N-duopropenide (NDP) in vivo (germicidal effect on flora of teams in the NICU and the pediatric intensive care unit vs handwashing with nonantiseptic soap) and its effect on the control of a multiresistant (MR) Klebsiella pneumoniae outbreak in our NICU that had persisted for 13 months, despite the use of classic control measures . For educational purposes, we also performed 4 prevalence studies of microbial hand flora in NICU staff (two before and two after introducing NDP) . The alcohol solution of NDP was highly germicidal in vivo, destroying microorganisms better than classic handwashing on the hands of 69 health care staff of our NICU and PICU . The flora in both units was reduced from an average of 63% to an average of 95% . Application of this disinfectant to the hands of health care workers after handling newborns helped to eliminate the MR Klebsiella strain in our NICU, (relative risk compared with the period preceding use of the disinfectant: 8.6, with 95% confidence intervals, 4.8-145.5) . Four prevalence studies of hand microbial contamination, before and after NDP introduction in the NICU, showed a significant reduction of enterobacteriaceae, mainly MR K pneumoniae, in health care workers . In conclusion, NDP in alcohol was very effective in vivo . It proved to be a useful complementary measure to handwashing and reduced exogenous microorganism transmission in a unit with a heavy patient-care workload.

Am J Infect Control, 2001 Jun, 29(3), 133 - 8
Reduction in colonization and nosocomial infection by multiresistant bacteria in a neonatal unit after institution of educational measures and restriction in the use of cephalosporins; Calil R et al.; INTRODUCTION: Previous administration of third-generation cephalosporins predisposes to colonization and infections by multiresistant Enterobacter sp . The emergence of multiresistant bacteria infections in a neonatal unit during 1995, especially Enterobacter cloacae, stimulated this study . OBJECTIVE: To evaluate the efficacy of measures to control colonization and nosocomial infection by multiresistant bacteria in a neonatal unit . SETTING: A tertiary care university hospital . PATIENTS AND METHODS: This study was conducted from October 1995 through December 1999 in 4 phases: a cross-sectional study, a longitudinal study with intervention measures, monthly cross-sectional studies, and determination of nosocomial infections caused by multiresistant bacteria (oxacillin-resistant Staphylococcus aureus and gram-negative bacteria resistant to either aminoglycosides or third-generation cephalosporins) . Specimens for surveillance culture were obtained through umbilical and rectal swabs, and tracheal aspirates from intubated babies . The intervention measures were as follows: (1) appropriated training of the whole health care team, emphasizing measures to reduce cross-colonization, and the importance of rational usage of antibiotics and (2) suppression of usage of third-generation cephalosporins . Risk factors were analyzed through univariate and multivariate logistic regression . RESULTS: In the first phase, 32% (10/31) of the patients were colonized by multiresistant bacteria (29% by multiresistant E cloacae ) . In the second phase, 342 patients were evaluated; 33% of them were colonized by E cloacae, and a multiresistant strain was isolated in 10.8% (37/342) of the babies . A logistic regression model indicated parenteral nutrition and antibiotic usage as risk factors for colonization by multiresistant E cloacae . In the third phase, for 6 months, only 2 patients were colonized by multiresistant E cloacae . In the fourth phase, the analysis of bacterial resistance profile indicated a reduction of nosocomial infections due to multiresistant bacteria from 18 cases in 1995 to 2 cases per year until 1999 . CONCLUSION: These results have shown that the measures adopted were effective.

Transplantation, 2001 May 27, 71(10), 1414 - 7
Bacterial translocation in clinical intestinal transplantation; Cicalese L et al.; BACKGROUND: Bacterial translocation (BT) has been suggested to be responsible for the high incidence of infections occurring after small bowel transplantation (SBTx) . Bacterial overgrowth, alteration of the mucosal barrier function as a consequence of preservation injury or acute rejection (AR), and potent immunosuppression are all associated with BT . The aim of this study was to evaluate and quantify the correlation of BT with these events . METHODS: Fifty pediatric SBTx recipients on tacrolimus and prednisone immunosuppression were analyzed . Blood, stool, and liver biopsies and peritoneal fluid were cultured (circa 4000 total specimens) when infection was clinically suspected or as part of follow-up . BT episodes were considered when microorganisms were found simultaneously in blood or liver biopsy and stool . RESULTS: BT (average of 2.0 episodes/patient) was evident in 44% of patients and was most frequently caused by Enterococcus, Staphylococcus, Enterobacter, and Klebsiella . The presence of a colon allograft was associated with a higher rate of BT (75% vs . 33.3%) . Furthermore, the transplantation procedure (colon vs . no colon) affected the rate of BT: SBTx=40% vs . 25%, combined liver and SBTx=100% vs . 30%, multivisceral transplantation=25% vs . 50% . AR was associated with 39% of BT episodes . BT followed AR in 9.6% of the cases . In 5.2% of the cases, positive blood cultures without stool confirmation of the bacteria were seen . Prolonged cold ischemia time (CIT) affected BT rate significantly (CIT>9 hr 76% vs . CIT<9 hr 20.8%) . CONCLUSIONS: This study shows that 1) a substantial percentage of, but not all, BT is associated with AR, 2) the presence of a colon allograft increases the risk for BT, and 3) a long CIT is associated with a high incidence of BT after SBTx.

J Antimicrob Chemother, 2001 Jun, 47(6), 773 - 80
Antibiotic susceptibility of bacterial strains isolated from urinary tract infections in Poland; Hryniewicz K et al.; Worldwide data show that there is increasing resistance among urinary tract pathogens to conventional drugs . The aim of this study was to obtain data on susceptibility patterns of pathogens responsible for urinary tract infections (UTIs) in Poland to currently used antimicrobial agents . A multicentre study of 141 pathogens from hospital-acquired infections and 460 pathogens from community-acquired infections was carried out between July 1998 and May 1999 . The most prevalent aetiological agent was Escherichia coli (73.0%), followed by Proteus spp . (8.9%) and other species of Enterobacteriaceae (9.6%) . Few community infections were caused by Gram-positive bacteria (2.2%) . Gram-positive cocci were isolated more frequently from a hospital setting (14.1%) and the most common were Enterococcus spp . (8.5%) . Pseudomonas aeruginosa was found only among hospital isolates and was responsible for 10.7% of infections . E . coli isolates from both community and hospital infections were highly susceptible to many antimicrobial agents with the exception of those isolates producing extended-spectrum beta-lactamases (ESBLs) . Of all Enterobacteriaceae tested, 38 strains (6.9%) were capable of producing ESBLs.

J Antimicrob Chemother, 2001 Jun, 47(6), 745 - 54
Characterization, cloning and sequence analysis of the inducible Ochrobactrum anthropi AmpC beta-lactamase; Higgins CS et al.; Ochrobactrum anthropi is resistant to most cephalosporins and penicillins due, at least in part, to the inducible expression of a single beta-lactamase . The beta-lactamase gene has been cloned and sequenced . It encodes an AmpC-type class 1 serine active-site enzyme that hydrolyses mainly cephalosporins and is resistant to inhibition by clavulanic acid . Expression of the ampC gene is inducible via a typical AmpR regulator, which is encoded upstream of ampC . Inducible expression is retained following cloning of O . anthropi ampR-ampC into Escherichia coli, confirming that the signal for AmpR activation in O . anthropi is the same as that used in the Enterobacteriaceae . This is the first reported example of an AmpC beta-lactamase outside of the gamma-subdivision of the bacterial kingdom . Genomic searches of other non-gamma-subdivision bacteria revealed a homologous ampR-ampC cluster in the plant symbiont, Sinorhizobium meliloti.

FEMS Microbiol Lett, 2001 May 30, 199(2), 241 - 6
Phenotypic variability of beta-glucoside utilization and its correlation to pathogenesis process in a few enteric bacteria; Kharat AS; Utilization of beta-glucosides is markedly variable in the members of the family Enterobacteriaceae . The results presented here provide molecular clues for evolutionary events that resulted in the phenotypic variability seen amongst the members of these species . The genomic hybridization of selected Enterobacteriaceae members with the Escherichia coli bgl and cel genes resulted in detection of a complete homolog of the bgl and cel operons in Shigella sonnei, a member that is evolutionarily closest to E . coli . However, the Salmonella group of organisms have been shown to carry only a homolog of bglR and bglG regions and the deletions of the bglF and bglB genes . Similarly, Proteus mirabilis, Enterobacter aerogenes and a non-enteric Gram-negative bacterium Pseudomonas aeruginosa have been shown to carry a homolog of the bglR and bglG regions and deletions of the bglF and bglB genes . The homolog of the cel operon could be identified in S . sonnei and Salmonella groups of organisms . Possible implications of these observations, in connection with the phenotypic variability seen in beta-glucoside utilization amongst these members, are discussed.

J Clin Microbiol, 2001 Jun, 39(6), 2184 - 90
Coexistence of SHV-4- and TEM-24-producing Enterobacter aerogenes strains before a large outbreak of TEM-24-producing strains in a French hospital; Mammeri H et al.; In 1996, a monitoring program was initiated at the teaching hospital of Amiens, France, and carried out for 3 years . All extended-spectrum beta-lactamase (ESBL)-producing Enterobacter aerogenes isolates recovered from clinical specimens were collected for investigation of their epidemiological relatedness by pulsed-field gel electrophoresis and enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and determination of the type of ESBL harbored by isoelectric focusing and DNA sequencing . Molecular typing revealed the endemic coexistence, during the first 2 years, of two clones expressing, respectively, SHV-4 and TEM-24 ESBLs, while an outbreak of the TEM-24-producing strain raged in the hospital during the third year, causing the infection or colonization of 165 patients . Furthermore, this strain was identified as the prevalent clone responsible for outbreaks in many French hospitals since 1996 . This study shows that TEM-24-producing E . aerogenes is an epidemic clone that is well established in the hospital's ecology and able to spread throughout wards . The management of the outbreak at the teaching hospital of Amiens, which included the reinforcement of infection control measures, failed to obtain complete eradication of the clone, which has become an endemic pathogen.

Appl Environ Microbiol, 2001 Jun, 67(6), 2404 - 9
Hydrolysis of 4-hydroxybenzoic acid esters (parabens) and their aerobic transformation into phenol by the resistant Enterobacter cloacae strain EM; Valkova N et al.; Enterobacter cloacae strain EM was isolated from a commercial dietary mineral supplement stabilized by a mixture of methylparaben and propylparaben . It harbored a high-molecular-weight plasmid and was resistant to high concentrations of parabens . Strain EM was able to grow in liquid media containing similar amounts of parabens as found in the mineral supplement (1,700 and 180 mg of methyl and propylparaben, respectively, per liter or 11.2 and 1.0 mM) and in very high concentrations of methylparaben (3,000 mg liter(-1), or 19.7 mM) . This strain was able to hydrolyze approximately 500 mg of methyl-, ethyl-, or propylparaben liter(-1) (3 mM) in less than 2 h in liquid culture, and the supernatant of a sonicated culture, after a 30-fold dilution, was able to hydrolyze 1,000 mg of methylparaben liter(-1) (6.6 mM) in 15 min . The first step of paraben degradation was the hydrolysis of the ester bond to produce 4-hydroxybenzoic acid, followed by a decarboxylation step to produce phenol under aerobic conditions . The transformation of 4-hydroxybenzoic acid into phenol was stoichiometric . The conversion of approximately 500 mg of parabens liter(-1) (3 mM) to phenol in liquid culture was completed within 5 h without significant hindrance to the growth of strain EM, while higher concentrations of parabens partially inhibited its growth.

Int Orthop, 2001, 25(1), 55 - 9
Urinary infection after orthopedic procedures; Herruzo-Cabrera R et al.; We have investigated prospectively the incidence of urinary tract infection (UTI) in 5320 orthopaedic patients . There were 74 UTIs (1.39%) . Enterobacteriaceae was the most frequent etiological agent . Each infection increased the length of stay in hospital by more than 8 days . Statistically independent risk factors for the development of urinary infection were a preoperative stay of more than 4 days, inadequate preoperative preventive measures, central venous catheterization and urinary catheterization . Sex, age, or type of surgery had no statistical influence on the development of infection.

Microbiol Res, 2001, 156(1), 75 - 82
Phenotypic and genotypic characterization of antagonistic bacteria associated with roots of transgenic and non-transgenic potato plants; Lottmann J et al.; Rhizobacteria obtained during a risk assessment study from parental and transgenic T4 lysozyme-expressing potato plants were investigated to determine whether or not the strains could be grouped based on the source of isolation, transgenic or non-transgenic plants, respectively . A total of 68 representative bacterial strains of the group of enterics and pseudomonads were investigated by phenotypic profiling (the antagonistic activity towards bacterial and fungal plant pathogens, the production of the plant growth hormone indole-3-acetic acid {auxin}, and the sensitivity to T4 lysozyme in vitro) and genotypic profiling by PCR fingerprints using BOX primers . All isolates were identified by fatty acid methyl ester (FAME) analysis . Computer-based analysis of the phenotypic characteristics showed that both, enterics and Pseudomonas strains clustered into six to seven groups at an Euclidian distance of 10 . According to their BOX-PCR-generated fingerprints the Pseudomonas strains clustered into seven groups and the enterobacteria into two groups at the same genetic distance level of 10 . The majority of groups were heterogeneous and contained isolates from all plant lines . In conclusion, cluster analysis of the phenotypic and genotypic features did not reveal correlations between bacterial isolates and transgenic character of plants.

J Bacteriol, 2001 Jun, 183(12), 3564 - 73
Genetic characterization of the Klebsiella pneumoniae waa gene cluster, involved in core lipopolysaccharide biosynthesis; Regue M et al.; A recombinant cosmid containing genes involved in Klebsiella pneumoniae C3 core lipopolysaccharide biosynthesis was identified by its ability to confer bacteriocin 28b resistance to Escherichia coli K-12 . The recombinant cosmid contains 12 genes, the whole waa gene cluster, flanked by kbl and coaD genes, as was found in E . coli K-12 . PCR amplification analysis showed that this cluster is conserved in representative K . pneumoniae strains . Partial nucleotide sequence determination showed that the same genes and gene order are found in K . pneumoniae subsp . ozaenae, for which the core chemical structure is known . Complementation analysis of known waa mutants from E . coli K-12 and/or Salmonella enterica led to the identification of genes involved in biosynthesis of the inner core backbone that are shared by these three members of the Enterobacteriaceae . K . pneumoniae orf10 mutants showed a two-log-fold reduction in a mice virulence assay and a strong decrease in capsule amount . Analysis of a constructed K . pneumoniae waaE deletion mutant suggests that the WaaE protein is involved in the transfer of the branch beta-D-Glc to the O-4 position of L-glycero-D-manno-heptose I, a feature shared by K . pneumoniae, Proteus mirabilis, and Yersinia enterocolitica.

Am J Respir Crit Care Med, 2001 May, 163(6), 1371 - 5
Resolution of infectious parameters after antimicrobial therapy in patients with ventilator-associated pneumonia; Dennesen PJ et al.; Although recommended durations of antimicrobial therapy for ventilator-associated pneumonia (VAP) range from 7 to 21 d, these are not based on prospective studies and little is known about the resolution of symptoms after start of antibiotics . Resolution of these symptoms was investigated in 27 patients . VAP was diagnosed on clinical, radiographic, and microbiological criteria, including quantitative cultures of bronchoalveolar lavage . All patients received appropriate antibiotic therapy . Highest temperatures, leukocyte counts, Pa(O(2))/FI(O(2)) ratios, and semiquantitative cultures of endotracheal aspirates were recorded from start of therapy until Day 14 . Resolution was defined as the first day that these parameters fulfilled the following definition: temperature < or = 38 degrees C, leukocytes < or = 10 x 10(9)/L, Pa(O(2))/FI(O(2)) ratio > or = 25 kPa, and no or +1 of bacterial growth of etiologic pathogens in cultures of endotracheal aspirate . VAP was caused by Enterobacteriaceae (n = 14), P . aeruginosa (n = 7), S . aureus (n = 6), H . influenzae (n = 3), and S . pneumoniae (n = 1) . H . influenzae and S . pneumoniae were eradicated from tracheal aspirates, whereas Enterobacteriaceae, S . aureus, and P . aeruginosa persisted, despite in vitro susceptibility to antibiotics administered . Significant improvements were observed for all clinical parameters, most apparently within the first 6 d after start of antibiotics . Newly acquired colonization, especially with P . aeruginosa and Enterobacteriaceae, occurred in the second week of therapy . Six patients developed a recurrent episode of VAP, four of them with P . aeruginosa . Clinical responses to therapy for VAP occur within the first 6 d of therapy, endotracheal colonization with Gram-negative bacteria persists despite susceptibility to therapy, and acquired colonization usually occurs in the second week of therapy and frequently precedes a recurrent episode.

Biochemistry, 2001 May 29, 40(21), 6233 - 9
Inhibition of class C beta-lactamases: structure of a reaction intermediate with a cephem sulfone; Crichlow GV et al.; The crystallographic structure of the Enterobacter cloacae GC1 extended-spectrum class C beta-lactamase, inhibited by a new 7-alkylidenecephalosporin sulfone, has been determined by X-ray diffraction at 100 K to a resolution of 1.6 A . The crystal structure was solved by molecular replacement using the unliganded structure {Crichlow et al . (1999) Biochemistry 38, 10256-10261} and refined to a crystallographic R-factor equal to 0.183 (R(free) 0.208) . Cryoquenching of the reaction of the sulfone with the enzyme produced an intermediate that is covalently bound via Ser64 . After acylation of the beta-lactam ring, the dihydrothiazine dioxide ring opened with departure of the sulfinate . Nucleophilic attack of a side chain pyridine nitrogen atom on the C6 atom of the resultant imine yielded a bicyclic aromatic system which helps to stabilize the acyl enzyme to hydrolysis . A structural assist to this resonance stabilization is the positioning of the anionic sulfinate group between the probable catalytic base (Tyr150) and the acyl ester bond so as to block the approach of a potentially deacylating water molecule . Comparison of the liganded and unliganded protein structures showed that a major movement (up to 7 A) and refolding of part of the Omega-loop (215-224) accompanies the binding of the inhibitor . This conformational flexibility in the Omega-loop may form the basis of an extended-spectrum activity of class C beta-lactamases against modern cephalosporins.

Arch Biochem Biophys, 2001 Jan 1, 385(1), 170 - 8
Quantitative structure-activity relationships in two-electron reduction of nitroaromatic compounds by Enterobacter cloacae NAD(P)H:nitroreductase; Nivinskas H et al.; Enterobacter cloacae NAD(P)H:nitroreductase (NR; EC 1.6.99.7) catalyzes the reduction of a series of nitroaromatic compounds with steady-state bimolecular rate constants (kcat/Km) ranging from 10(4) to 10(7) M(-1) s(-1) . In agreement with a previously proposed scheme of two-step four-electron reduction of nitroaromatics by NR (Koder, R . L., and Miller, A.-F . (1998) Biochim . Biophys . Acta 1387, 395-405), 2 mol NADH per mole mononitrocompound were oxidized . An oxidation of excess NADH by polinitrobenzenes, including explosives 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenyl-N-methylnitramine (tetryl), has been observed as a slower secondary process, accompanied by O2 consumption . This type of "redox cycling" was not related to reactions of nitroaromatic anion-radicals, but was caused by the autoxidation of relatively stable reaction products . The initial reduction of tetryl and other polinitrophenyl-N-nitramines by E . cloacae NR was analogous to a two-step four-electron reduction mechanism of TNT and other nitroaromatics . The logs kcat/Km of all the compounds examined exhibited parabolic dependence on their enthalpies of single-electron or two-electron (hydride) reduction, obtained by quantum mechanical calculations . This type of quantitative structure-activity relationship shows that the reactivity of nitroaromatics towards E . cloacae nitroreductase depends mainly on their hydride accepting properties, but not on their particular structure, and does not exclude the possibility of multistep hydride transfer.

Can J Microbiol, 2001 Apr, 47(4), 368 - 72
Levels of ACC and related compounds in exudate and extracts of canola seeds treated with ACC deaminase-containing plant growth-promoting bacteria; Penrose DM et al.; It was previously proposed that plant growth-promoting bacteria that possess 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase could utilize ACC that is present in the exudate of germinating canola seeds . The uptake and cleavage of ACC by these bacteria would lower the level of ACC, and thus ethylene within the plant, and reduce the extent of its inhibition on root elongation . To test part of the above mentioned model, ACC levels were monitored in canola seed tissues and exudate during germination . Lower amounts of ACC were present in the exudate and tissues of seeds treated with the plant growth-promoting bacterium Enterobacter cloacae CAL3, than in control seeds treated with MgSO4 . The ACC-related compounds, alpha- and gamma-aminobutyric acids, both known to stimulate ethylene production, were also measured in the canola seed exudate and tissues . Approximately the same levels of alpha-aminobutyric acid were present in the exudates of the bacterium-treated seeds and the control seeds, but the amount of alpha-aminobutyric acid was lower in the tissues of the bacterium-treated seeds than in the control seeds . Smaller quantities of gamma-aminobutyric acid were seen in both the exudate and tissues of the E . cloacae CAL3-treated seeds than in the control seeds.

Can J Microbiol, 2001 Apr, 47(4), 359 - 67
Transcriptional regulation of the Enterobacter cloacae UW4 1-aminocyclopropane-1-carboxylate (ACC) deaminase gene (acdS); Li J et al.; Based on DNA sequence analysis and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, the region of DNA immediately upstream of the Enterobacter cloacae UW4 ACC deaminase gene (acdS) contains several features that appear to be involved in its transcriptional regulation . In the present study, the 5' upstream region of acdS was cloned into the promoter-probe vector, pQF70, which carries the promoterless luciferase gene (luxAB), and luciferase expression was monitored . The data obtained from studying the expression of the luciferase gene showed that (i) a leucine responsive regulatory protein (LRP)-like protein encoded within the upstream region is located on the opposite strand from acdS under the control of a promoter stronger than the one responsible for acdS transcription, (ii) luciferase gene expression required both ACC and the LRP-like protein, (iii) luciferase expression was increased three-fold under anaerobic conditions, consistent with the involvement of a fumarate-nitrate reduction (FNR)-like regulatory protein box within the upstream region, and (iv) the addition of leucine to the growth medium decreased luciferase activity in the presence of ACC and increased luciferase activity in the absence of ACC, consistent with leucine acting as a regulator of the expression of the LRP-like protein.

Rev Pneumol Clin, 2001 Apr, 57(2), 132 - 8
{Epidemiology and antibiotic therapy in nosocomial pneumonia}; Fagon JY; Nosocomial pneumonia occurs in 0.5 to 1.5% of all hospitalized patients and in 10 to 30% of those under artificial ventilation . The main causal agents are Staphylococcus aureus and resistant Gram-negative bacilli, particularly Pseudomonas aeruginosa . In case of early onset (before the fifth day), Haemophilus influenzae, Streptococcus pneumoniae and susceptible enterobacteria predominate . These infections are associated with overmortality, particularly in patients with P . aeruginosa pneumonia, severe respiratory failure, shock syndrome or given a poorly adapted antibiotic regimen . Management of patients with nosocomial pneumonia depends on the clinical presentation and prior bacteriology data often leading to empiric antibiotic prescription . Published guidelines, for example those recommended by the American Thoracic Society, can also be used to adapt the antibiotic therapy as a function of the severity of the clinical situation, the patient's comorbidities, and the date of onset . This type of strategy remains to be evaluated . It would be advisable to base therapeutic management on reliable microbiological data allowing selection of patients requiring antibiotics and treatment based on culture results . Currently a two-drug regimen is recommended for nosocomial pneumonia due to P . aeruginosa or particularly resistant strains.

Antimicrob Agents Chemother, 2001 Jun, 45(6), 1923 - 7
In vitro activities of three nonfluorinated quinolones against representative bacterial isolates; Barry AL et al.; In vitro susceptibility tests were performed to document the inhibitory activities of three nonfluorinated quinolone (NFQ) compounds (PGE 9262932, PGE 9509924, and PGE 4175997) compared to those of ciprofloxacin, levofloxacin, and trovafloxacin against 3,030 bacterial isolates . The spectra of the NFQ agents included most gram-positive species as well as quinolone-susceptible Enterobacteriaceae . Ciprofloxacin-resistant, methicillin-resistant Staphylococcus aureus strains were inhibited by the NFQ series at < or =1.0 microg/ml . The NFQ compounds were not very active against Pseudomonas aeruginosa and most other nonfermentative gram-negative bacilli . Against other species, the potency of the NFQ agents was similar to that of trovafloxacin . Continued investigation of the NFQ compounds seems to be warranted.

Antimicrob Agents Chemother, 2001 Jun, 45(6), 1915 - 8
In vitro activities of ertapenem (MK-0826) against clinical bacterial isolates from 11 North American medical centers; Fuchs PC et al.; This study compared the in vitro activities of the new long-half-life carbapenem ertapenem (also known as MK-0826 and L-749,345) with those of imipenem, amoxicillin-clavulanate, and ciprofloxacin against 5,558 recent clinical isolates from 11 North American medical centers . We confirmed the greater activity of ertapenem than of imipenem against the Enterobacteriaceae and the greater activity of imipenem against pseudomonads and gram-positive bacteria.

Pharmacotherapy, 2001 May, 21(5), 583 - 92
Therapeutic challenges associated with extended-spectrum, beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae; Wong-Beringer A; The emergence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, particularly Escherichia coli and Klebsiella pneumoniae, presents significant diagnostic and therapeutic challenges to the management of infections due to these organisms . Detection of resistant isolates is difficult based on routine susceptibility testing performed by a clinical microbiology laboratory . In addition, the utility of penicillins, cephalosporins, and aztreonam in treating serious infections due to these organisms is uncertain due to reports of treatment failure despite apparent in vitro susceptibility . A critical evaluation of the English literature was performed on treatment outcomes associated with ESBL-producing Enterobacteriaceae . Imipenem and extended-spectrum cephalosporins were commonly administered . Discordant outcomes in relation to in vitro susceptibility of the agent did not occur exclusively with cephalosporins but with all drugs including imipenem . Until more outcome data are available, drug selection must take into consideration whether or not an outbreak is occurring and whether therapy is empirical or definitive.

J Food Prot, 2001 May, 64(5), 721 - 4
Effects of epiphytic Enterobacteriaceae and pseudomonads on the growth of Listeria monocytogenes in model media; Campo JD et al.; Four Enterobacteriaceae (Enterobacter agglomerans and Rhanella aquatilis) and six pseudomonads (Pseudomonas fluorescens, Pseudomonas chlororaphis, Pseudomonas putida) isolated from minimally processed green endive were coinoculated at 10 degrees C with Listeria monocytogenes in a minimal medium . Pseudomonads did not modify the growth of L . monocytogenes, whereas Enterobacteriaceae reduced its maximal population by 2 to 3 log CFU/ml . The same effect was observed in a diluted yeast extract medium supplemented with amino acids and glucose, in which L . monocytogenes grown alone reached 10(9) to 10(10) CFU/ml . In the same diluted yeast extract medium, not supplemented with glucose and amino acids, the maximal population of L . monocytogenes in the presence of both Enterobacteriaceae and pseudomonads was only slightly reduced (less than 0.5 log CFU/ml) . Culture filtrates of the Enterobacteriaceae had no inhibitory activity on L . monocytogenes . The effect of the Enterobacteriaceae on L . monocytogenes growth was presumably due to a competition for glucose and/or amino acids.

J Food Prot, 2001 May, 64(5), 635 - 9
Evaluation of surface contamination and the presence of Listeria monocytogenes in fish processing factories; Miettinen H et al.; The main objective of this study was to determine the level of surface contamination in fish processing factories and the presence of Listeria in the factory environment and products . Another objective was evaluation of the different hygiene-monitoring methods . Total aerobic heterotrophic and enterobacteria, yeast and mold samples were collected and ATP levels measured in 28 factories . The number of well or adequately washed and disinfected factories was small (2 of 28), in terms of total aerobic heterotrophic bacterial counts on the surfaces . Most surfaces contaminated with bacteria were heavily contaminated . Results of the ATP and the total bacteria contact agar slide methods were poorly correlated (r = 0.21) although 68% of the samples were categorized as good to moderate or unacceptable with both methods . The Listeria-positive surface samples usually contained increased numbers of total bacteria (70.9%) . The contamination of products and raw fish together with Listeria spp . was 45% and with Listeria monocytogenes 12% . Cold smoked fish was the most contaminated, with 75% Listeria spp . and cold salted fish with 20% L . monocytogenes . Listeria innocua was found in the samples more than twice as often as L . monocytogenes.

J Bacteriol, 2001 Jun, 183(11), 3318 - 27
Functional analysis of the galactosyltransferases required for biosynthesis of D-galactan I, a component of the lipopolysaccharide O1 antigen of Klebsiella pneumoniae; Guan S et al.; D-Galactan I is an O-antigenic polymer with the repeat unit structure {-->3)-beta-D-Galf-(1-->3)-alpha-D-Galp-(1-->}, that is found in the lipopolysaccharide of Klebsiella pneumoniae O1 and other gram-negative bacteria . A genetic locus containing six genes is responsible for the synthesis and assembly of D-galactan I via an ATP-binding cassette (ABC) transporter-dependent pathway . The galactosyltransferase activities that are required for the processive polymerization of D-galactan I were identified by using in vitro reactions . The activities were determined with endogenous lipid acceptors in membrane preparations from Escherichia coli K-12 expressing individual enzymes (or combinations of enzymes) or in membranes reconstituted with specific lipid acceptors . The D-galactan I polymer is built on a lipid acceptor, undecaprenyl pyrophosphoryl-GlcpNAc, a product of the WecA enzyme that participates in the biosynthesis of enterobacterial common antigen and O-antigenic polysaccharide (O-PS) biosynthesis pathways . This intermediate is directed into D-galactan I biosynthesis by the bifunctional wbbO gene product, which sequentially adds one Galp and one Galf residue from the corresponding UDP-sugars to form a lipid-linked trisaccharide . The two galactosyltransferase activities of WbbO are separable by limiting the UDP-Galf precursor . Galactosyltransferase activity in membranes reconstituted with exogenous lipid-linked trisaccharide acceptor and the known structure of D-galactan I indicate that WbbM catalyzes the subsequent transfer of a single Galp residue to form a lipid-linked tetrasaccharide . Chain extension of the D-galactan I polymer requires WbbM for Galp transferase, together with Galf transferase activity provided by WbbO . Comparison of the biosynthetic pathways for D-galactan I and the polymannose E . coli O9a antigen reveals some interesting features that may reflect a common theme in ABC transporter-dependent O-PS assembly systems.

Biochim Biophys Acta, 2001 Feb 9, 1510(1-2), 185 - 97
Physico-chemical analysis of lipid A fractions of lipopolysaccharide from Erwinia carotovora in relation to bioactivity; Fukuoka S et al.; Highly purified bisphosphoryl, monophosphoryl and dephosphoryl lipids A from Erwinia carotovora with different acylation patterns were characterized physico-chemically . Applying matrix assisted laser desorption/ionization mass spectrometry, the purity of the lipid A fractions was determined, and from monolayer measurements the molecular space requirement was estimated . Fourier transform infrared spectroscopy allowed the elucidation of the gel to liquid crystalline phase transition of the acyl chains as well as the determination of the tilt angle of the diglucosamine backbone with respect to the acyl chain direction applying dichroitic measurements with attenuated total reflectance . With synchrotron radiation small-angle X-ray diffraction the supramolecular aggregate structure was determined, and with fluorescence resonance energy transfer spectroscopy the lipopolysaccharide binding protein induced intercalation of lipid A into a phospholipid matrix corresponding to that of the macrophage membrane was investigated . From the results, a clear dependence of the physico-chemical parameters on the particular lipid A structure can be followed . Furthermore, these parameters correlate well with the biological activities of the various lipids A as deduced from their ability to induce biological activity (Limulus assay and cytokine induction in mononuclear cells) . These results contribute to a closer interpretation of the physico-chemical prerequisites for endotoxic activity as found for enterobacterial lipid A.

Infection, 2001 Mar-Apr, 29(2), 75 - 9
Adult Enterobacter meningitis: a high incidence of coinfection with other pathogens and frequent association with neurosurgical procedures; Huang CR et al.; BACKGROUND: The clinical characteristics of Enterobacter infection in adult bacterial meningitis were defined . PATIENTS AND METHODS: The clinical manifestations and therapeutic outcomes of ten adult patients with Enterobacter infections in acute bacterial meningitis were analyzed . RESULTS: Enterobacter infection was found in 4.5% (10/223) of our adult patients with culture-proven bacterial meningitis . The ten patients comprised seven men and three women aged between 16-69 years (mean 47 years) . Coinfections with other pathogens were found in 50% of the cases, the most common pathogen being Klebsiella pneumoniae . Nine of the ten patients had a history of neurosurgery, and seven patients contracted the infection nosocomially . Multiple antibiotic-resistant strains, including resistance to third-generation cephalosporins, were found in three patients with polymicrobial infections . These three patients received iv imipenem/cilastin therapy . The therapeutic results showed that two of the ten patients died; five of the eight surviving patients had neurological sequelae . CONCLUSION: The predominant coinfection with Enterobacteriaceae in adult Enterobacter meningitis may reflect the fact that most of the cases of polymicrobial Enterobacter infections have a potential gastrointestinal source . A postneurosurgical state was the most important predisposing factor for the development of Enterobacter infection in adult bacterial meningitis in our patients . The strains of the Enterobacter species in adult polymicrobial Enterobacter meningitis were commonly resistant to multiple antibiotics, including third-generation cephalosporins . In light of the high incidence of multiple antibiotic-resistant Enterobacter strains in adult polymicrobial Enterobacter meningitis, the choice of initial empiric antibiotics may include carbapenem (imipenem/cilastin or meropenem) . Although the mortality rate was not high in this group of patients, most survivors suffered neurological sequelae.

J Med Microbiol, 2001 May, 50(5), 396 - 406
Natural antibiotic susceptibility of Klebsiella pneumoniae, K . oxytoca, K . planticola, K . ornithinolytica and K . terrigena strains; Stock I et al.; The natural susceptibility of 221 Klebsiella strains to 71 antibiotics was examined . The strains were isolated from clinical specimens and the environment, and belonged to K . pneumoniae subsp . pneumoniae (n = 40), K . pneumoniae subsp . ozaenae (37), K . pneumoniae subsp . rhinoscleromatis (10), K . oxytoca (44), K . planticola (40), K . ornithinolytica (25) and K . terrigena (25) . MIC values were determined by a microdilution procedure in IsoSensitest broth according to the German standard (DIN) . All Klebsiella spp . were naturally resistant or intermediate to amoxicillin, ticarcillin and to antibiotics to which other Enterobacteriaceae are also intrinsically resistant . Klebsiella spp . were naturally sensitive or intermediate to several penicillins, all tested cephalosporins, aminoglycosides, quinolones, tetracyclines, trimethoprim, cotrimoxazole, chloramphenicol and nitrofurantoin . K . pneumoniae subsp . ozaenae and subsp . rhinoscleromatis strains were generally more susceptible to antibiotics than strains of other Klebsiella taxa . K pneumoniae subsp . rhinoscleromatis was the most susceptible taxon, being highly susceptible to cefuroxime, anti-folates and naturally intermediate to erythromycin and clarithromycin . K . pneumoniae subsp . ozaenae was most susceptible to glycopeptides . K . oxytoca and K . terrigena strains were least susceptible to cefazoline, cefoperazone and fosfomycin, respectively . The results of the present study describe a database of the natural antimicrobial susceptibility of Klebsiella spp., which can be used for the validation of antibiotic susceptibility results of these bacteria . MIC patterns to beta-lactams indicate the expression of chromosomally encoded class A gamma-lactamases in all the species, including the subspecies of K . pneumoniae . Similar natural susceptibility patterns of K . planticola and K . ornithinolytica to all tested antibiotics support the status of K . ornithinolytica as a biovar of K . planticola.

Int J Antimicrob Agents, 2001 May, 17(5), 371 - 6
Performance of the VITEK2 system for identification and susceptibility testing of routine Enterobacteriaceae clinical isolates; Perez-Vazquez M et al.; The VITEK2 system was evaluated with 138 fresh consecutive routine clinical Enterobacteriaceae isolates . Susceptibility results to 10 beta-lactams, three aminoglycosides and a quinolone were compared with those obtained following the NCCLS standard microdilution . API20E was used as reference method for identification . All but three isolates were correctly identified in 3 h at species level (97.8%), two isolates (1.4%) at genus level and only one isolate was misidentified . Overall essential agreement for susceptibility testing was 97.1% . Discrepancies were mainly observed with piperacillin (1.1%), cefuroxime (0.6%) and amoxycillin/clavulanate (0.3%) . Discrepancies for aminoglycosides and ciprofloxacin were low (<0.1%) . Minor, major and very major errors (NCCLS categories) were 4.1%, 0.2% and 6.1%, respectively . Very major errors were due to piperacillin (4.5%), ampicillin (0.8%) and amoxycillin/clavulanate (0.8%) . The VITEK2 system gave accurate identification and susceptibility testing results of routine Enterobacteriaceae clinical isolates.

Avian Dis, 2001 Jan-Mar, 45(1), 173 - 81
Genetic variability of avian Escherichia coli strains evaluated by enterobacterial repetitive intergenic consensus and repetitive extragenic palindromic polymerase chain reaction; Carvalho de Moura AC et al.; In this study, we tested the capability of enterobacterial repetitive intergenic consensus (ERIC) and repetitive extragenic palindromic (REP) polymerase chain reaction (PCR) to detect genetic diversity among Escherichia coli strains isolated from chickens bearing clinical signs of colibacillosis and compared the genotypes so obtained with the O:H serotypes and virulence of those strains . The DNAs from 50 avian E . coli strains and from E . coli ATCC 25922 were used to amplify ERIC and REP sequences . DNA from avian strains produced from 8 to 17 bands by ERIC-PCR and from 6 to 20 bands by REP-PCR; E . coli ATCC produced 11 bands by both methods . ERIC and REP-PCR showed good discriminating power, and the dendograms based on the different patterns revealed extensive genetic diversity among the avian strains . Those strains were allocated into four major clonal clusters, each one with 60% of similarity by ERIC and REP-PCR, and those clusters corresponded to strains with different degrees of pathogenicity . However, 56% of the pathogenic strains (28/50) belonged to two out of three major clonal clusters, and 86% of the nonpathogenic strains tended to group in one cluster and one subgroup . The 32 serotypes detected were distributed in all clusters, and within a serogroup, different DNA fingerprints were observed; however, strains with same serotypes tended to form clusters with similarity coefficients greater than 80% . These results suggest that no specific serotype and genotype is responsible for colibacillosis and that REP and ERIC-PCR are reproducible techniques that can improve the studies needed to clarify the pathways to the pathogenesis of colibacillosis.

Acta Paediatr, 2001 Mar, 90(3), 356 - 8
Enterobacter sakazakii infection in the newborn; Bar-Oz B et al.; Enterobacter sakazakii, a Gram-negative bacillus, previously known as "yellow pigmented Enterobacter cloacae", is a rare cause of neonatal infection . We describe the detailed clinical presentation of two cases in whom E . sakazakii was isolated in our neonatal service during the course of 1 mo . These include one case of sepsis and meningitis complicated by cerebral infarction, and one case of sepsis . In addition, three cases of intestinal colonization were identified . The source of the organism was thoroughly sought and was found to be a blender in the milk kitchen that was used for preparation of the reconstituted powdered milk formula . CONCLUSION: Our paper adds clinical and laboratory information about the disease spectrum caused by this relatively rare organism and emphasizes the importance of a thorough search for the source of the infection.

J Chemother, 2001 Apr, 13(2), 195 - 201
Enterobacter spp . infections complicating the course of HIV disease; Manfredi R et al.; Through a retrospective review of clinical and laboratory data of 2517 consecutive patients with HIV disease hospitalized since 1991, 13 patients were identified (0.52%), who suffered from a confirmed Enterobacter spp . infection (urinary tract disease in 7 cases, sepsis in 4 patients, and pneumonia in 2 cases) . A severe immunodeficiency was recognized in all cases, as expressed by a mean CD4+ lymphocyte count <60 cells/microL, and frequently, a prior diagnosis of AIDS . Bloodstream infection proved linked to a lower mean CD4+ cell count, a more frequent occurrence of leukopenia-neutropenia, and nosocomial origin of the infecting pathogen . Hospital-acquired Enterobacter spp . disease was more frequent than community-acquired, and was significantly associated with leukopenia-neutropenia, and a diagnosis of AIDS . Antibiotic susceptibility assays showed a resistance rate to ampicillin and cephalothin involving >90% of tested strains, and a higher (but varied) sensitivity to other beta-lactams, aminoglycosides, fluoroquinolones, and cotrimoxazole . Adequate chemotherapy provided clinical and bacteriological success in all evaluated patients, in the absence of mortality or relapses . Only 34 episodes of HIV-associated Enterobacter spp . infection have been reported to date in 11 different literature studies . Our data point out that also Enterobacter spp . organisms may have an appreciable pathogenic potential in patients with HIV disease, especially in those with a low CD4+ lymphocyte count, leukopenia-neutropenia, who are hospitalized . Despite the unpredictable antibiotic susceptibility profile of these organisms, HIV-related Enterobacter spp . disease may be properly managed through rapid identification and timely and appropriate antimicrobial treatment.

Biochemistry, 2001 Feb 13, 40(6), 1550 - 9
Asparagine 23 and aspartate 305 are essential residues in the active site of UDP-N-acetylglucosamine enolpyruvyl transferase from Enterobacter cloacae; Samland AK et al.; UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) catalyzes the transfer of the intact enolpyruvyl moiety of phosphoenolpyruvate (PEP) to the 3'-hydroxyl group of UDP-N-acetylglucosamine (UDPNAG) . This reaction constitutes the first committed step in the biosynthesis of the bacterial cell wall component peptidoglycan (murein) . The transfer reaction involves the nucleophilic attack of the 3'-hydroxyl group of UDPNAG at the C-2 of PEP . The three-dimensional structure of MurA complexed with UDPNAG revealed an aspartate residue (D305 in the En . cloacae sequence) close to the 3'-hydroxyl group of UDPNAG, suggesting that it may act as an acid-base catalyst in the active center of the enzyme . In addition to aspartate 305, asparagine 23 also interacts with the 3'-hydroxyl group; however, its role in catalysis or binding of the UDPNAG substrate is unclear . To gain information on the role of these two amino acids in the MurA-catalyzed reaction we have exchanged D305 for alanine, cysteine, histidine, and glutamate, and N23 for alanine and serine using site-directed mutagenesis . While the D305 alanine, cysteine, and histidine mutant proteins do not have detectable enzymatic activity, the D305E mutant protein exhibits a low residual activity (ca . 0.1% of the wild-type enzyme) . Unlike with wild-type MurA, no exothermic signal was obtained when the D305A and -E mutant proteins were titrated with UDPNAG, demonstrating that the affinity of the sugar nucleotide substrate is reduced as a result of the amino acid exchange . The reduced affinity to UDPNAG leads to a lower propensity of C115 to form either the O-phosphothioketal with PEP or the thioether with the antibiotic fosfomycin . These findings emphasize the dual role of D305 as a general base and an essential binding partner to UDPNAG in the active site of MurA . Similarly, the two N23 mutant proteins showed a much lower catalytic activity although binding of UDPNAG was not as much affected as in the case of the D305 mutant proteins . This result indicates that this amino acid residue is mainly involved in stabilization of transition states.

J Clin Microbiol, 2001 May, 39(5), 1985 - 8
Evidence of in vivo transfer of a plasmid encoding the extended-spectrum beta-lactamase TEM-24 and other resistance factors among different members of the family Enterobacteriaceae; Neuwirth C et al.; The epidemiological study of several multidrug-resistant Enterobacteriaceae isolated from five patients demonstrated in vivo dissemination of a 100-kb plasmid encoding the extended-spectrum beta-lactamase TEM-24 from a clonal strain of Enterobacter aerogenes to different strains of Klebsiella pneumoniae, Escherichia coli, Proteus vulgaris, Proteus mirabilis, and Serratia marcescens.

J Clin Microbiol, 2001 May, 39(5), 1865 - 70
Dynamics of a nosocomial outbreak of multidrug-resistant Pseudomonas aeruginosa producing the PER-1 extended-spectrum beta-lactamase; Luzzaro F et al.; From November 1998 to August 1999, a large outbreak occurred in the general intensive care unit of the Ospedale di Circolo in Varese (Italy), caused by Pseudomonas aeruginosa producing the PER-1 extended-spectrum beta-lactamase . A total of 108 clinical isolates of P . aeruginosa resistant to broad-spectrum cephalosporins were recovered from 18 patients . Epidemic isolates were characterized by synergy between clavulanic acid and ceftazidime, cefepime, and aztreonam . Isoelectric focusing of crude bacterial extracts detected two nitrocefin-positive bands with pI values of 8.0 and 5.3 . PCR amplification and characterization of the amplicons by restriction analysis and direct sequencing indicated that the epidemic isolates carried a bla(PER-1) determinant . The outbreak was of clonal origin as shown by pulsed-field gel electrophoresis analysis . This technique also indicated that the epidemic strain was not related to three other PER-1-positive isolates obtained at the same hospital in 1997 . Typing by enterobacterial repetitive intergenic consensus-PCR showed that minor genetic variations occurred during the outbreak . The epidemic strain was characterized by a multiple-drug-resistance phenotype that remained unchanged over the outbreak, including extended-spectrum cephalosporins, monobactams, aminoglycosides, and fluoroquinolones . Isolation of infected patients and appropriate carbapenem therapy were successful in ending the outbreak . Our report indicates that the bla(PER-1) resistance determinant may become an emerging therapeutic problem in Europe.

J Clin Microbiol, 2001 May, 39(5), 1845 - 9
Adaptation of Escherichia coli to the bovine mammary gland; Bradley AJ et al.; Clinical mastitis in six Somerset dairy herds was monitored over a 12-month period . Escherichia coli was implicated in 34.7% of all clinical cases . Forty-one percent of all clinical E . coli mastitis cases occurred in just 2.2% of the population . A total of 23.9% of clinical E . coli cases occurred in quarters suffering recurrent cases of E . coli mastitis . The genotypes of strains involved in recurrent cases of clinical E . coli mastitis were compared by DNA fingerprinting with enterobacterial repetitive intergenic consensus primers . In 85.7% of cases of recurrent quarter E . coli mastitis, the same genotype was implicated as the cause of disease, suggesting persistence of the organism within the mammary environment . The same genotype as that in the original case was also implicated in 8.5% of recurrent cases occurring in different quarters of the same cow, suggesting spread between quarters . These findings challenge our current understanding of the epidemiology of E . coli mastitis and suggest that pathogen adaptation and host susceptibility may be playing a part in the changing pattern of clinical mastitis experienced in the modern dairy herd.

J Bacteriol, 2001 May, 183(10), 3134 - 41
Osmoregulated periplasmic glucan synthesis is required for Erwinia chrysanthemi pathogenicity; Page F et al.; Erwinia chrysanthemi is a phytopathogenic enterobacterium causing soft rot disease in a wide range of plants . Osmoregulated periplasmic glucans (OPGs) are intrinsic components of the gram-negative bacterial envelope . We cloned the opgGH operon of E . chrysanthemi, encoding proteins involved in the glucose backbone synthesis of OPGs, by complementation of the homologous locus mdoGH of Escherichia coli . OpgG and OpgH show a high level of similarity with MdoG and MdoH, respectively, and mutations in the opgG or opgH gene abolish OPG synthesis . The opg mutants exhibit a pleiotropic phenotype, including overproduction of exopolysaccharides, reduced motility, bile salt hypersensitivity, reduced protease, cellulase, and pectate lyase production, and complete loss of virulence . Coinoculation experiments support the conclusion that OPGs present in the periplasmic space of the bacteria are necessary for growth in the plant host.

J Bacteriol, 2001 May, 183(10), 3127 - 33
Osmoregulated periplasmic glucans of Erwinia chrysanthemi; Cogez V et al.; We report the initial characterization of the osmoregulated periplasmic glucans (OPGs) of Erwinia chrysanthemi . OPGs are intrinsic components of the bacterial envelope necessary to the pathogenicity of this phytopathogenic enterobacterium (F . Page, S . Altabe, N . Hugouvieux-Cotte-Pattat, J.-M . Lacroix, J . Robert-Baudouy and J.-P . Bohin, J . Bacteriol . 183:0000-0000, 2001 {companion in this issue}) . OPGs were isolated by trichloracetic acid treatment and gel permeation chromatography . The synthesis of these compounds appeared to be osmoregulated, since lower amounts of OPGs were produced when bacteria were grown in media of higher osmolarities . However, a large fraction of these OPGs were recovered in the culture medium . Then, these compounds were characterized by compositional analysis, high-performance anion-exchange chromatography, matrix-assisted laser desorption mass spectrometry, and (1)H and (13)C nuclear magnetic resonance analyses . OPGs produced by E . chrysanthemi are very heterogeneous at the level of both backbone structure and substitution of these structures . The degree of polymerization of the glucose units ranges from 5 to 12 . The structures are branched, with a linear backbone consisting of beta-1,2-linked glucose units to which a variable number of branches, composed of one glucose residue, are attached by beta-1,6 linkages in a random way . This glucan backbone may be substituted by O-acetyl and O-succinyl ester-linked residues.

Int J Food Microbiol, 2001 Apr 11, 65(1-2), 113 - 23
Effect of the interaction between a low tyramine-producing Lactobacillus and proteolytic staphylococci on biogenic amine production during ripening and storage of dry sausages; Bover-Cid S et al.; The interaction between tyrosine-decarboxylase and proteolytic activities of a Lactobacillus curvatus and Staphylococcus xylosus, respectively, on biogenic amine production during the ripening and the storage of dry fermented sausages was investigated . Water content, pH, proteolysis parameters, microbial counts, and biogenic amine contents were monitored in spontaneously and starter fermented sausages . The use of proteolytic staphylococci as starter resulted in a higher content of non-protein nitrogen and total free amino acids . Tyramine was the main amine produced in all batches . However, tyrosine-decarboxylase activity of the L . curvatus starter strain was weak and yielded lower amounts of tyramine than those produced by the wild mioroflora in the control batch . Association between tyramine production and proteolysis could only be established in a defectively dried batch . Putrescine and cadaverine accumulation was efficiently reduced in the starter-mediated fermentation, in agreement with the lower development of enterobacteria . Phenylethylamine and tryptamine were only detected in the spontaneously fermented sausages, while histamine, spermine and spermidine did not vary during the ripening . Biogenic amine levels and related parameters showed significant changes during the storage of dry sausages depending on the temperature and the batch . As a general rule, changes in the pH, proteolysis, microbial counts, and biogenic amine contents were stronger at 19 degrees C than at 4 degrees C . The results suggest that refrigeration would be advisable for preventing further accumulation of biogenic amines during the storage of dry fermented sausages.

J Mol Microbiol Biotechnol, 2001 Apr, 3(2), 319 - 24
Comparative approach to analysis of regulation in complete genomes: multidrug resistance systems in gamma-proteobacteria; Rodionov DA et al.; Comparative approach is a powerful tool for analysis of gene regulation in bacterial genomes . Here we apply it to analysis of regulation of the multidrug resistance transport (MDRT) systems in enterobacteria Escherichia coli, Salmonella typhi, Klebsiella pneumoniae and Yersinia pestis . Comparison of nucleotide sequences upstream of MDRT genes was performed in order to predict new regulatory sites (operators) and identify candidate regulons . Since the regulatory sites diverge slower than the non-coding regions in general, they are visible as strongly conserved islands . This analysis resulted in description of a regulatory network for known and hypothetical MDRT systems and porins . New candidate members of the MarA regulon were detected . Putative binding sites for EmrR and AcrR were suggested . A new hypothetical MarX regulon was described that includes some multidrug transporters and porins.

Int J Syst Evol Microbiol, 2001 Mar, 51(Pt 2), 513 - 26
Molecular characterization of planktic cyanobacteria of Anabaena, Aphanizomenon, Microcystis and Planktothrix genera; Lyra C et al.; Toxic and non-toxic cyanobacterial strains from Anabaena, Aphanizomenon, Calothrix, Cylindrospermum, Nostoc, Microcystis, Planktothrix (Oscillatoria agardhii), Oscillatoria and Synechococcus genera were examined by RFLP of PCR-amplified 16S rRNA genes and 16S rRNA gene sequencing . With both methods, high 16S rRNA gene similarity was found among planktic, anatoxin-a-producing Anabaena and non-toxic Aphanizomenon, microcystin-producing and non-toxic Microcystis, and microcystin-producing and non-toxic Planktothrix strains of different geographical origins . The respective sequence similarities were 99.9-100%, 94.2-99.9% and 99.3-100% . Thus the morphological characteristics (e.g . Anabaena and Aphanizomenon), the physiological (toxicity) characteristics or the geographical origins did not reflect the level of 16S rRNA gene relatedness of the closely related strains studied . In addition, cyanobacterial strains were fingerprinted with repetitive extragenic palindromic (REP)- and enterobacterial repetitive intergenic consensus (ERIC)-PCR . All the strains except two identical pairs of Microcystis strains had different band profiles . The overall grouping of the trees from the 16S rRNA gene and the REP- and ERIC-PCR analyses was similar . Based on the 16S rRNA gene sequence analysis, four major clades were formed . (i) The clade containing filamentous heterocystous cyanobacteria was divided into three discrete groups of Anabaena/Aphanizomenon, Anabaena/Cylindrospermum/ Nodularia/Nostoc and Calothrix strains . The three other clades contained (ii) filamentous non-heterocystous Planktothrix, (iii) unicellular non-heterocystous Microcystis and (iv) Synechococcus strains.

Med Pregl, 2000 Nov-Dec, 53(11-12), 564 - 7
{Analysis of the plasmid profile of various Salmonella serotypes}; Jelesic Z et al.; INTRODUCTION: Every year foodborne infections cause millions of illnesses but many of them go undiagnosed and unreported . The epidemiology of these illnesses is changing, new pathogens have emerged (Escherichia coli O157:H7, Cyclospora cayetanensis, Vibrio vulnificus) . Salmonella spp . is the most common bacterial cause of acute enterocolitis with us . All over the world, as well as in our country the most often isolated serotype is Salmonella Enteritidis . A great problem in many countries is the multiresistant Salmonella Typhimurium, as well as other serotypes resistant to a great number of antimicrobial drugs (S . Hadar, S . Typhi) . Clinical microbiologists are often asked to determine the relatedness of bacterial isolates . Recently, traditional methods of strain typing such as bacteriophage typing, resistotyping and serotyping, have been supplemented or replaced in many laboratories with newer molecular methods such as plasmid fingerprinting, ribotyping . PCR-based methods, etc . The goal of strain typing is to provide evidence that epidemiologically related isolates collected during an outbreak are also genetically related and thus represent the same strain . MATERIAL AND METHODS: In the laboratory for Enterobacteriaceae of the Institute of Public Health Novi Sad in the four year period (1995-1998) 3659 primary isolates of Salmonella spp . were isolated using standard bacteriological methods (cultural, biochemical and serological examination) . For certain strain of Salmonella Enteritidis, S . Typhimurium and S . Hadar susceptibility to antimicrobial agents was tested by disc-diffusion test (Kirby-Bauer) and plasmid profiles were analyzed . Plasmid DNA was extracted by Birnboim and Doly alkaline lysis method and plasmid bands were separated by electrophoresis in agarose gel . RESULTS: In the period of 1995-1998 the most common serotype isolated was Salmonella Enteritidis with 3017 (82.5%) of the total number of isolated Salmonellas; S . Typhimurium 203 (5.5%), S . Hadar 118 (3.2%) . Plasmid profiles were tested in 10 S . Enteritidis isolates that originated from patients with sporadic cases of diarrhea . All investigated strains had one plasmid band with molecular weight of 38 MDa . All isolates were susceptible to all antibiotics tested . Ten isolates of S . Hadar originated from one outbreak from food samples and stools of patients with diarrheal disease and from the worker in the restaurant . All isolates were resistant to ampicillin and streptomycin, and plasmid profile analysis showed 5 plasmid bands with molecular weights of 13, 5.4, 4.2, 2.0 and 1.7 MDa . Chosen strains of S . Typhimurim were not epidemically related . Strains number 1, 3, 4, 5 were susceptible to all antibiotics tested, and had only one plasmid of 50 MDa, strain number 7 was resistant to streptomycin and had 2 plasmid bands of 50 and 1.7 MDa, other strains were multiresistant and had different plasmid profiles with 4-7 plasmid bands with molecular weights ranging from 50-1.4 MDa . CONCLUSION: Plasmid profile analysis is not a sufficient method for examination of Salmonella Enteritidis which is the most common cause of enterocolitis with us . It is, however, a helpful method for proving epidemiological and clonal relatedness of Salmonella isolates that are resistant to antimicrobial agents and have a great number of plasmids (such as some strains of S . Typhimurim and S . Hadar).

Clin Infect Dis, 2001 May 15, 32 Suppl 2, S94 - 103
Variations in the prevalence of strains expressing an extended-spectrum beta-lactamase phenotype and characterization of isolates from Europe, the Americas, and the Western Pacific region; Winokur PL et al.; To evaluate the prevalence of extended-spectrum beta-lactamase (ESBL)-producing strains among species of Enterobacteriaceae, a microdilution susceptibility test was performed with strains of Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, and Salmonella species that were isolated as part of the SENTRY project . The highest percentage of ESBL phenotype (defined as a minimum inhibitory concentration {MIC} > or =2 microg/mL for ceftazidime, ceftriaxone, or aztreonam) was detected among K . pneumoniae strains from Latin America (45%), followed by those from the Western Pacific region (25%), Europe (23%), the United States (8%), and Canada (5%) . P . mirabilis and E . coli strains for which MICs of extended-spectrum cephalosporins or monobactams were elevated also were more prominent in Latin America . Testing with ceftazidime revealed more isolates with elevated MICs than did testing with ceftriaxone or aztreonam . ESBL strains showed high levels of co-resistance to aminoglycosides, tetracycline, trimethoprim-sulfamethoxazole, and ciprofloxacin . Imipenem remains highly effective against ESBL strains . Organisms expressing an ESBL are widely distributed worldwide, although prevalence rates are significantly higher in certain geographic regions.

J Ind Microbiol Biotechnol, 2000 Dec, 25(6), 305 - 309
Purification, cloning, and characterization of an arylsulfotransferase from the anaerobic bacterium Eubacterium rectale IIIH; Goldberg SL et al.; A bacterium, Eubacterium rectale IIIH, which possessed arylsulfotransferase (ASST) activity was isolated from human feces . The ASST gene (astA) was cloned and the corresponding protein partially characterized . This gene shows only moderate homology to the previously sequenced ASST genes of Klebsiella and Enterobacter, which are very closely related to each other.

Ann Dermatol Venereol, 2001 Mar, 128(3 Pt 2), 394 - 403
{The therapeutic approach to necrotizing fasciitis}; Brun-Buisson C; Necrotizing fasciitis are characterized by the necrosis of fascias, and their severe consequences in terms of morbidity and mortality . An early diagnosis, based on sometimes subtle cutaneous lesions (associated to a sepsis syndrome) allows to start resuscitation and decide on a probable surgery . 3 major forms can be distinguished: streptococcal fasciitis, due to beta-hemolytic streptococci, often following minor trauma, and increasingly associated to a streptococcal toxic shock syndrome (STTS); clostridial gangrene (often polymicrobial when developed on a open wound or after surgery); and synergistic gangrene due to a mixed aerobic-anaerobic flora . Other apparently "primitive" necrotizing fasciitis, caused by specific organisms, may occur in debilitated patients . The prognosis depends on age, comorbidity, and above all on the severity of the sepsis syndrome . Initial resuscitation involves controlling the hypotension and organ dysfunction associated with severe sepsis, and is usually dominated by a severe hypovolemia . Penicillin G remains the key antibiotic for streptococcal and clostridial fasciitis, with a broad spectrum including enterobacteriaceae, streptococci and enterococci, and anaerobes (including Bacteroides spp.) in other types or when the etiology is unknown . In patients presenting with STSS, a combination of clindamycin (or rifampin) to penicillin is recommended, because of their effect on exotoxin production; administration of non-specific immunoglobulins also appears to improve the outcome of patients affected . Hyperbaric oxygen therapy has not proved effective . Early surgical debridement largely influences the prognosis . The prevention of complications associated with long-term intensive care, including early nutritional support and prevention of a thromboembolic disease, is also important.

Sante, 2001 Jan-Feb, 11(1), 63 - 6
{Antimicrobial activity of ciprofloxacin and netilmicin compared to various antibiotics in Lome, Togo}; Dagnra AY et al.; We report the antimicrobial activity of ciprofloxacin and netilmicin on 577 strains such as S . aureus, Pseudomonas, E . coli, Salmonella, Proteus, Klebsiella and Enterobacter . Isolation and identification were performed by standard methods . Disk diffusion tests were performed to evalute the susceptibility . The percentage resistance to ciprofloxacin for bacteria was: E . coli = 15%, Enterobacter = 13%, Proteus = 10%, Pseudomonas = 9%, S . aureus and Klebsiella = 4% . The percentage resistance to netilmicin for bacteria was: Pseudomonas = 29%, Proteus = 26%, S . aureus = 21%, Enterobacter = 16%, Klebsiella = 14% and E . coli = 5% . The antimicrobial activity of ciprofloxacin and netilmicin was higher than that of others antibiotics.

FEMS Microbiol Lett, 2001 Apr 13, 197(2), 139 - 43
Use of repetitive DNA elements to define genetic relationships among Anaplasma marginale isolates; Ferreira AM et al.; Anaplasma marginale genomic DNA was tested for the presence of repetitive extragenic palindromic (REP) and enterobacterial repetitive intergenic consensus (ERIC)-like sequences in order to evaluate the genetic diversity of multiple A . marginale isolates . A . marginale isolates were obtained from cattle of six different states of Brazil, from the US and an Anaplasma centrale strain was obtained from Uruguay . Patterns obtained from A . marginale isolates varied from 14 to 17 fragments by REP-polymerase chain reaction (PCR) and 6 to 14 fragments by ERIC-PCR . All A . marginale isolates presented a 0.75-kb fragment by REP and two common fragments (0.38 and 1.0 kb) by ERIC-PCR . These two fragments were not detectable in A . centrale . Both methods produced similar patterns (80%) among A . marginale isolates obtained from the same region, although some isolates within regions shared less similarity . Isolates from Parana and Pernambuco, were differentiated by these methods . The study demonstrates the presence of ERIC and REP-like elements in A . marginale isolates and shows that A . marginale isolates and strains can be differentiated by these methods.

FEMS Microbiol Ecol, 2001 May, 35(3), 239 - 247
Effect of Photorhabdus luminescens phase variants on the in vivo and in vitro development and reproduction of the entomopathogenic nematodes Heterorhabditis bacteriophora and Steinernema carpocapsae; Han R et al.; Photorhabdus luminescens (Enterobacteriaceae) is a symbiont of entomopathogenic nematodes Heterorhabditis spp . (Nematoda: Rhabditida) used for biological control of insect pests . For industrial mass production, the nematodes are produced in liquid media, pre-incubated with their bacterial symbiont, which provides nutrients essential for the nematode's development and reproduction . Particularly under in vitro conditions, P . luminescens produces phase variants, which do not allow normal nematode development . The phase variants were distinguished based on dye absorption, pigmentation, production of antibiotic substances, occurrence of crystalline inclusion proteins and bioluminescence . To understand the significance of the phase shift for the symbiotic interaction between the bacterium and the nematode, feeding experiments tested the effect of homologous and heterologous P . luminescens phase variants isolated from a Chinese Heterorhabditis bacteriophora (HO6), the Heterorhabditis megidis type strain from Ohio (HNA) and the type strain of Heterorhabditis indica (LN2) on the in vivo and in vitro development and reproduction of the nematode species H . bacteriophora (strain HO6) and another rhabditid and entomopathogenic nematode, Steinernema carpocapsae (A24) . In axenically cultured insect larvae (Galleria mellonella) and in vitro in liquid media, H . bacteriophora produced offspring on phase I of its homologous symbiont and on the heterologous symbiont of H . megidis, but not on the two corresponding phase II variants . In solid media, nematode yields were much lower on phase II than on phase I variants . On the heterologous phase I symbiont isolated from H . indica the development of H . bacteriophora was not beyond the fourth juvenile stage of the nematode in any of the media tested, but further progressed on phase II with even a small amount of offspring recorded in solid media . Infective juveniles of S . carpocapsae did not develop beyond the J3 stage on all phase I P . luminescens . They died in phase I P . luminescens isolated from H . bacteriophora . Development to adults was recorded for S . carpocapsae on all phase II symbionts and offspring were produced in all media except in liquid . It is concluded that a lack of essential nutrients or the production of toxins is not responsible for the negative impact of homologous phase II symbiont cells on the development and reproduction of H . bacteriophora . The infective juveniles of H . bacteriophora retained cells of the homologous phase I symbiont, but not phase II cells and cells from heterologous symbionts, indicating that the transmission of the symbiont by the infective juvenile is selective for phase I cells and the homologous bacterial associate.

Lab Invest, 2001 Mar, 81(3), 375 - 84
Helicobacter pylori lipopolysaccharide hinders polymorphonuclear leucocyte apoptosis; Hofman V et al.; A prominent histologic feature of Helicobacter pylori infection is a dense infiltration of polymorphonuclear leukocytes (PMNL) in gastric mucosa . H . pylori lipopolysaccharide (LPS) has been recognized as a primary virulence factor evoking acute mucosal inflammatory reaction . Previous works have shown that H . pylori LPS immunologic activities are lower than those of enterobacterial LPS . However, the effect of H . pylori LPS on spontaneous PMNL apoptosis, and mechanisms by which this H . pylori LPS may promote PMNL survival remain to be established . In this study, we investigated, by both morphologic and biochemical approaches, the action of H . pylori LPS on PMNL apoptosis in vitro, using broth culture filtrates (BCF) of H . pylori strains with different genotypes . We found that BCF from H . pylori caused a significant delay in spontaneous PMNL apoptosis and this delay was independent of the VacA, cag pathogenicity island and urease status . We demonstrated that LPS in BCF is responsible for this effect because it was abrogated by the LPS antagonist B287 (a synthetic analog of Rhodobactersphaeroides lipid A) . Moreover, BCF from H . pylori induced P42/44MAP kinase activation in PMNL . Similar results were obtained with BCF of an Escherichia coli strain . Taken together these data suggest that longer survival of PMNL induced by H . pylori LPS may increase gastric epithelium injury in H . pylori-associated diseases.

Paediatr Drugs, 2001, 3(3), 219 - 27
Urinary tract infections in children younger than 5 years of age: epidemiology, diagnosis, treatment, outcomes and prevention; Schlager TA; Although the true incidence of urinary tract infections (UTIs) in children is difficult to estimate, they are one of the most common bacterial infections seen by clinicians who care for young children . Except for the first 8 to 12 weeks of life, when infection of the urinary tact may be secondary to a haematogenous source, UTI is believed to arise by the ascending route after entry of bacteria via the urethra . Enterobacteriaceae are the most common organisms isolated from uncomplicated UTI . Infection with Staphylococcus aureus is rare in children without in-dwelling catheters or other sources of infection, and coagulase-negative staphylococci and Candida spp . are associated with infections after instrumentation of the urinary tract . The diagnosis of UTI in young children is important as it is a marker for urinary tract abnormalities and, in the newborn, may be associated with bacteraemia . Early diagnosis is critical to preserve renal function of the growing kidney . A urine specimen for culture is necessary to document a UTI in a young child . Prior to culture, urinalysis may be useful to detect findings supporting a presumptive diagnosis of UTI . The goals of the management of UTI in a young child are: (i) prompt diagnosis of concomitant bacteraemia or meningitis, particularly in the infant; (ii) prevention of progressive renal disease by prompt eradication of the bacterial pathogen, identification of abnormalities of the urinary tract and prevention of recurrent infections; and (iii) resolution of the acute symptoms of the infection . Delay in initiation of the antibacterial therapy is associated with an increased risk of renal scarring . The initial choice of antibacterial therapy is based on the knowledge of the predominant pathogens in the patient's age group, antibacterial sensitivity patterns in the practice area, the clinical status of the patient and the opportunity for close follow-up . Imaging studies to detect congenital or acquired abnormalities are recommended following the first UTI in all children aged <6 years . Patients with significant urinary tract abnormalities and/or frequent symptomatic UTI may benefit from prophylactic antibacterials . The main long term consequence of UTI is renal scarring which may lead to hypertension and end-stage renal disease . Prevention of recurrent UTI focuses on detection, and correction if possible, of urinary tract abnormalities . Interventions that have been associated with a decrease in symptomatic UTI in children with a history of recurrent UTI include relief of constipation and voiding dysfunction.

J Appl Microbiol, 2001 Apr, 90(4), 578 - 87
Research of quality indices for cold-smoked salmon using a stepwise multiple regression of microbiological counts and physico-chemical parameters; Leroi F et al.; AIMS: The aim of the study was to assess the relationships between the remaining shelf-life (RSL) of cold-smoked salmon and various microbiological and physico-chemical parameters, using a multivariate data analysis in the form of stepwise forward multiple regression . METHODS AND RESULTS: Thirteen batches of French cold-smoked salmon were analysed weekly during vacuum-packed storage at 5 degrees C for their lipid, water, salt, phenol, pH, total volatile basic nitrogen (TVBN) and trimethylamine contents, total psychrotrophic count, lactic acid bacteria, lactobacilli, B . thermosphacta, Enterobacteriaceae and yeast counts . At the sensory rejection time, the flora was dominated by lactobacilli, lactobacilli/Enterobacteriaceae or Carnobacteria/B . thermosphacta . Shelf-life was very variable (1->6 weeks) and was related to the initial Enterobacteriaceae load (P < 0.05), depending on hygienic conditions in the smokehouse . High correlations existed between the RSL and lactobacilli count (P < 0.01), yeast count (P < 0.05) and TVBN concentration (P < 0.01) . A polynomial fitting the RSL as a function of those three factors was proposed (R(2) = 0.80) . Assuming that lactobacilli count could not exceed 109 cfu g-1, a minimum of 36 mg-N 100 g-1 was necessary for a product to be rejected, with a yeast count of 104 cfu g-1 . CONCLUSION: Estimation of cold-smoked salmon quality is possible by measuring three parameters: lactobacilli and yeast counts and TVBN concentration . SIGNIFICANCE AND IMPACT OF THE STUDY: The technical content is important for the smoked salmon industry and for development of quality standards for cold-smoked salmon.

J Food Prot, 2001 Apr, 64(4), 498 - 502
Microbiological quality of chilled beef carcasses in Northern Ireland: a baseline survey; Murray KA et al.; To standardize the assessment of the hygienic quality of beef carcasses in Northern Ireland (NI) abattoirs, swabbing techniques were evaluated . Six materials, including two commercially produced swabs, were compared for their ability to recover spoilage and pathogenic bacteria and for their ease of use as carcass swabs . A sponge retailed for domestic use was selected on the basis of efficiency of recovery of microorganisms, ease of use, and cost . On sample carcasses, 1,000 cm2 of the brisket was swabbed, since this site is normally readily contaminated . For 9 months, 420 carcasses in seven of the nine European Union-approved abattoirs in NI were sampled while in the chiller (24 to 48 h after kill) . Total viable count (TVC), yeasts and molds, and Enterobacteriaceae were enumerated after incubation at 22 (48 h) and 37 degrees C (48 h), and the results were expressed as log CFU/cm2 . The mean TVC results at 22 and 37 degrees C were 2.80+/-0.70 and 2.75+/-0.64, respectively . Although 63% of samples had yeasts that grew at 22 degrees C, only 35% were positive at 37 degrees C . The respective mean yeast counts were 1.12+/-0.59 and 0.46+/-0.51 . Enterobacteriaceae were present in 15% of samples at 22 degrees C and 21% of samples at 37 degrees C . The mean counts for positive samples were 0.41+/-0.37 and 0.40+/-0.30, respectively . Molds were found in less than 4% of samples . Given that the brisket is normally one of the most heavily contaminated parts of the carcass, these results suggest that good hygienic practices are in operation in NI abattoirs . The results also enabled the abattoirs with the cleanest carcasses to be identified, hence permitting best practices to be found.

Medicine (Baltimore), 2001 Mar, 80(2), 113 - 22
Enterobacter sakazakii infections among neonates, infants, children, and adults . Case reports and a review of the literature; Lai KK; Enterobacter sakazakii can cause serious infections especially among the very young and the elderly . It continues to be more common among neonates and infants than adults . Its tropism for the central nervous system in neonates and infants remains a mystery . Among neonates and infants, E . sakazakii has a propensity to cause meningitis resulting in ventriculitis, brain abscess or cyst formation, and development of hydrocephalus requiring ventricular-peritoneal shunt . Computed tomography of the head is therefore useful in following patients with E . sakazakii meningitis . Mortality and morbidity of E . sakazakii meningitis is high, and virtually all patients recovering from the central nervous system infection suffered mental and physical developmental delays . The case-fatality rate decreased among patients with meningitis treated with the third-generation cephalosporins . Most adults with E . sakazakii infection had serious underlying diseases and 50% of the adults with the infection had malignancies . However there has never been a known case of meningitis . Increasing antibiotic resistance among Enterobacter species should lead one to consider using the carbapenems or the newer cephalosporins in combination with a second agent such as an aminoglycoside . Limited data suggest that trimethoprim-sulfamethoxazole may be a useful agent in the treatment of infections caused by the Enterobacter species, especially in view of the production of extended-spectrum beta-lactamases capable of inactivating the cephalosporins and extended-spectrum penicillin.

Eur J Clin Microbiol Infect Dis, 2001 Feb, 20(2), 97 - 103
Development of a latex agglutination test for rapid identification of Escherichia coli; Huang YH et al.; Escherichia coli, one of the most important human pathogens, is usually identified by a battery of biochemical tests that require overnight incubation . For rapid identification of Escherichia coli, a latex agglutination test (LAT) was developed . Rabbits were immunized with cell-surface antigens extracted from Escherichia coli CCRC 15481 with 4 M urea, and the affinity-purified antibodies were used to coat latex particles for the identification of the bacterium . The following gram-negative bacteria were used to evaluate the LAT: Escherichia coli (n = 761), Enterobacteriaceae other than Escherichia coli (n = 632), Aeromonas spp . (n = 21), Pseudomonas spp . (n = 75), Vibrio spp . (n = 18), and other bacteria (n = 64) . The LAT had a sensitivity and specificity of 99.2 and 93.3%, respectively . If the LAT was used in conjunction with the tests of indole production or lactose fermentation, the specificity values for the identification of Escherichia coli increased from 93.3 to 98.8 and 98.7%, respectively . If the LAT, indole production, and lactose fermentation were used together for the identification of Escherichia coli, the sensitivity and specificity were 94 and 99.7%, respectively . Lactose fermentation could be detected by observing the colonies grown on selective media (e.g . MacConkey agar), and indole production could be analyzed simply by the spot indole test . Strains producing negative reactions (i.e . not identified as Escherichia coli) should be processed by the conventional procedures for identification . The present protocol integrating the LAT, indole production, and lactose fermentation for the identification of Escherichia coli offers considerable savings of time, manpower, and cost.

Ned Tijdschr Geneeskd, 2001 Mar 31, 145(13), 643 - 7
{Enterobacter cloacae epidemic on a neonatal intensive care unit due to the use of contaminated thermometers}; Donkers LE et al.; From December 1999 to March 2000 a nosocomial outbreak of multiresistant Enterobacter cloacae occurred in the neonatal intensive care unit (NICU) at the VU Medical Center, Amsterdam, the Netherlands . Twenty-six patients were infected or colonized with this strain resistant to third generation cephalosporins and with decreased sensitivity for aminoglycosides . Three neonates experienced sepsis with E . cloacae with serious clinical symptoms and two of them died . Comparison of the Enterobacter isolates by amplified-fragment length polymorphism indicated that this outbreak was caused by the spread of a single strain . Infection control precautions were initiated in order to stop further spread; barrier precautions, enforcement of hand disinfection and cohorting of colonized patients . A multidisciplinary crisis team coordinated these infection control precautions and informed all persons involved . Analysis of antibiotic usage in 1999 showed an increase in the use of third generation cephalosporins from November onwards . Due to the resistance pattern of the epidemic strain the use of third generation cephalosporins was discontinued in February 2000 . At the end of February the NICU was temporarily closed . The epidemic strain of E . cloacae was isolated from one digital rectal thermometer . Patient use of thermometers and disposable coverings for rectal thermometers were introduced to eliminate this possible means of spread . No spread of multiresistant E . cloacae was found following the introduction of these interventions . Once all the neonates had been transferred, the NICU was disinfected and reopened in March.

Scand J Infect Dis, 2001, 33(3), 188 - 93
Clinical significance and impact on mortality of extended-spectrum beta lactamase-producing Enterobacteriaceae isolates in nosocomial bacteremia; Menashe G et al.; During an 8-month period, 55 episodes of nosocomial bacteremia caused by Enterobacteriaceae species were identified in a tertiary medical center, of which 26 (47%) were caused by extended-spectrum beta lactamase (ESBL)-producing organisms . ESBL production was associated with resistance to aminoglycosides, fluoroquinolones, tetracycline and co-trimoxazole compared with non-ESBL-producing organisms (p < 0.01) . By multivariate analysis, infection with ESBL-producing organisms was associated with previous antibiotic therapy and central venous catheter insertion and mortality was associated with heart failure, malignancy and a prolonged hospital stay . Nineteen (73%) patients infected with ESBL-producing organisms received adequate empirical antibiotic therapy and all 26 received adequate definitive therapy . The in-hospital mortality rate did not differ between patients infected with ESBL producers and those infected by non-ESBL-producing Enterobacteriaceae species {13/26 (50%) and 11/29 (38%), respectively} (p > 0.5).

Biosci Biotechnol Biochem, 2001 Feb, 65(2), 456 - 8
Isolation and characterization of the Enterobacter cloacae cheR mutant defective in phosphate taxis; Kato J et al.; A chemotaxis-defective mutant of Enterobacter cloacae IFO3320, designated EC1, was isolated after N-methyl-N'-nitro-N-nitrosoguanidine (NTG) mutagenesis . Computer-assisted capillary assays showed that EC1 failed to show chemotactic responses to peptone and inorganic phosphate (Pi) . Cloning and sequence analysis showed that EC1 is a cheR mutant, suggesting that Pi taxis by E . cloacae is dependent on a methyl-accepting chemotaxis protein(s) (MCP) . EC1 was further mutagenized with NTG to construct cheR pstS and cheR pstA double mutants . A recombinant plasmid pECT01.2, which contained the E . cloacae cheR gene, restored the ability of these double mutants to show chemotaxis toward peptone but not Pi . These results suggest that the phosphate-specific transport (Pst) system, together with a MCP(s), is required for detecting Pi in E . cloacae.

Bioorg Chem, 2001 Apr, 29(2), 77 - 95
The relative catalytic efficiency of beta-lactamase catalyzed acyl and phosphyl transfer; Slater MJ et al.; Phosphonamidates which bear a simple resemblance to penicillin type structures have been synthesised as potential inhibitors of beta-lactamases: -ethyl N-(benzyloxycarbonyl) amidomethyl phosphonyl amides, PhCH(2)OCONHCH(2)P(O)(OEt)NR(2), the amines HNR(2) being l-proline, d-proline, l-thiazolidine, and o-anthranilic acid . The proline derivatives completely and irreversibly inactivated the class C beta-lactamase from Enterobacter cloacae P99, in a time-dependent manner, indicative of covalent inhibition . The inactivation was found to be exclusive to the class C enzyme and no significant inhibition was observed with any other class of beta-lactamase . The anthranilic acid derivative exhibited no appreciable inactivation of the beta-lactamases . The phosphonyl proline and phosphonyl thioproline derivatives were separated into their diastereoisomers and their individual second order rate constants for inhibition were found to be 7.72 +/- 0.37 and 8.3 x 10(-2) +/- 0.004 M(-1) s(-1) for the l-proline derivatives, at pH 7.0 . The products of the inhibition reaction of each individual diastereoisomer, analyzed by electrospray mass spectroscopy, indicate that the more reactive diastereoisomers phosphonylate the enzyme by P-N bond fission with the elimination of proline . Conversely, gas chromatographic detection of ethanol release by the less reactive proline diastereoisomer suggests phosphonylation occurs by P-O bond fission . The enzyme enhances the rate of phosphonylation with P-N fission by at least 10(6) compared with that effected by hydroxide-ion . The pH dependence of the rate of inhibition of the beta-lactamase by the more reactive diasteroisomer is consistent with the reaction of the diprotonated form of the enzyme, EH(2), with the inhibitor, I (or its kinetic equivalents EH with IH) . This pH dependence and the rate enhancement indicate that the enzyme appears to use the same catalytic apparatus for phosphonylation as that used for hydrolysis of beta-lactams . The stereochemical consequences of nucleophilic displacement at the phosphonyl centre are discussed .

Biochemistry, 2001 Mar 27, 40(12), 3623 - 8
Conformational investigation of a cyclic enterobacterial common antigen employing NMR spectroscopy and molecular dynamics simulations; Staaf M et al.; The three-dimensional structure of a cyclic enterobacterial common antigen (ECA) having four trisaccharide repeating units has been investigated by NMR spectroscopy and molecular dynamics simulations . Three different NMR parameters were determined: (a) (1)H,(1)H cross-relaxation rates from NOE experiments were used for determination of proton-proton distances; (b) trans-glycosidic (3)J(C,H) scalar coupling constants analyzed via a Karplus-type relationship provided information on torsion angles; and (c) (1)H,(13)C one-bond dipolar couplings obtained in a dilute liquid-crystalline medium were interpreted in terms of the orientational order and molecular conformations . The molecular dynamics simulations of the dodecasaccharide were performed with explicit water and counterions, which are important factors that strongly influence molecular conformation . Subsequently, the results from computer simulation were used to generate a three-dimensional structure of the cyclic ECA which is consistent with the experimental NMR parameters.

Biochemistry, 2001 Apr 17, 40(15), 4610 - 21
Mechanism of reaction of acyl phosph(on)ates with the beta-lactamase of Enterobacter cloacae P99; Kaur K et al.; A series of acyl phosph(on)ates has been prepared to more closely examine the details of the interactions of this class of molecule with beta-lactamases . In general, they were found to react with the class C beta-lactamase of Enterobacter cloacae P99 in two ways, by acylation and by phosphylation . The acyl-enzymes generated by the former reaction were transiently stable with half-lives of between 3 and 45 s, of comparable lifetime therefore to those generated by the inhibitory beta-lactams cefotaxime, cefuroxime, and cefoxitin . On the other hand, phosphylation led to a completely inactive enzyme . In general, the second-order rate constants for acylation (k(cat)/K(m)) were larger than for phosphylation (k(i)) . As expected on chemical grounds, phosphylation was found to be relatively more effective for the phosphonates than the phosphates . The acyl phosphates were much more effective acylating agents however . The acylation reaction was found to be enhanced by hydrophobic substituents in both the acyl and leaving group moieties . Thus, the most reactive compound in this series was benzo{b}thiophene-2-carbonyl 2'-naphthyl phosphate with a K(m) value of 0.15 microM and a k(cat) of 0.2 s(-1); k(cat)/K(m) is therefore 1.3 x 10(6) s(-1) M(-1), making this compound the most specific acyclic acylation reagent for this beta-lactamase yet described . Significant substrate inhibition by this compound suggested that further binding regions may be available for exploitation in inhibitor design . A linear free energy analysis showed that the transition states for acylation of the beta-lactamase by aroyl phosphates are analogues of the corresponding aryl boronic acid adducts . Molecular modeling suggested that the aroyl phosphates react with the P99 beta-lactamase with the aroyl group in the side chain/acyl group site of normal substrates and the phosphate in the leaving group site . In this orientation, the phosphate leaving group interacts strongly with Lys 315.

Acta Microbiol Pol, 2000, 49(3-4), 217 - 24
Isolation and insecticidal effects of some bacteria from Euproctis chrysorrhoea L . (Lepidoptera: Lymantriidae); Yaman M et al.; In this study, we investigated the bacterial pathogens of Euproctis chrysorrhoea and tested for their insecticidal activities . Based on colony color and morphology, four isolates were determined . According to morphological, physiological and biochemical characters of the isolates, they were identified as Enterobacter aerogenes, Lactobacillus sp., Bacillus thuringiensis and Micrococcus luteus . The insecticidal effects of these bacterial isolates on third-fourth instar larvae of Euproctis chrysorrhoea were investigated . The highest insecticidal effect determined on this pest is 68% with Bacillus thuringiensis . The effects of the other isolates are 45% with Enterobacter aerogenes, 15% Micrococcus luteus and 0% with Lactobacillus sp.

Am J Infect Control, 2001 Apr, 29(2), 94 - 8
Unique epidemiology of nosocomial urinary tract infection in children; Langley JM et al.; BACKGROUND: Nosocomial urinary tract infection (NUTI) occurs with varying frequency in children and is thought to be associated with urethral instrumentation . In response to changing infection control resources at our facility, we reviewed NUTI to determine whether the frequency of NUTI, associated complications, or presence of a remediable risk factor (instrumentation) justified ongoing routine infection control surveillance . METHODS: Prospective surveillance was conducted on all wards 8 months per year from January 1991 through December 1997 by an infection control nurse coordinator . NUTI was defined by laboratory evidence according to Center for Disease Control and Prevention definitions and detected 48 hours after admission . Urinary catheterization in the previous 7 days was categorized as continuous/indwelling or intermittent . RESULTS: NUTI was the fifth most common nosocomial infection (129/1375; approximately 9%) and decreased in frequency during the decade from 0.9 to approximately 0.6 cases/1000 patient days . Incidence was equal among men and women . Only 50% of cases had prior instrumentation of the urinary tract . NUTI occurred disproportionately in newborns and infants (P <.001) . The most common pathogen was Escherichia coli (28%; 38/132), followed by Candida sp (18%; 24/134), Enterococcus (13%; 18/134), gram-negative nonfermenters (13%; 17/132), Enterobacter (approximately 10%; 13/134), Pseudomonas (9.7%; 13/134), and other (16%; 22/134) . Three cases of secondary bacteremia occurred (2.3%; 95% confidence interval 0.5-6.6); there was no mortality . CONCLUSIONS: NUTI poses a less significant burden of illness (incidence, associated morbidity) than other nosocomial infection in children . If resources do not permit hospital-wide surveillance, high-risk children with urethral instrumentation and newborns and infants could be targeted . Although E coli remains the most common cause of pediatric NUTI, fungi have become the second most common pathogen in this tertiary care population . Risk factors for NUTI in noncatheterized children remain to be delineated.

Curr Infect Dis Rep, 2001 Apr, 3(2), 123 - 130
Recent Advances in the Management of Infections in Liver Transplant Recipients; Singh N; Antimicrobial-resistant bacteria (vancomycin-resistant enterococci and Staphylococcus aureus) have emerged as leading pathogens in liver transplant recipients . Liver transplant recipients have also been shown to be uniquely more susceptible to harboring extended-spectrum beta-lactamase-producing Enterobacteriaceae . The frequency of mycelial fungal infections has increased; however, effective prophylaxis and management of these infections remains suboptimal . Emerging reports have highlighted the morbidity due to novel herpesviruses in these patients . Finally, the emergence of ganciclovir resistance in cytomegalovirus has implications relevant for all solid organ transplant recipients.

Microbiology, 2001 Apr, 147(Pt 4), 1059 - 67
Topological investigations of the FomA porin from Fusobacterium nucleatum and identification of the constriction loop L6; Kleivdal H et al.; Porin FomA in the outer membrane of Fusobacterium nucleatum is a trimeric protein, which exhibits permeability properties similar to that of the well-known enterobacterial diffusion porins . The proposed topology model of the FomA monomer depicts the beta-barrel motif typical of diffusion porins, consisting of 16 antiparallel beta-strands . To investigate the accuracy of the FomA model and assess the topological relationship with other porins, individual deletions of variable size in seven of the eight surface-exposed regions of the porin were genetically engineered . Deletions in the predicted loops L1 to L7 were tolerated by the FomA porins, as judged by a normal assembly in the outer membrane of Escherichia coli and a sustained pore-forming ability . Deletions in the largest proposed external region, loop L6, made the FomA porins considerably more permeable to antibiotics, indicating larger pore channels . The distinctly increased uptake rates and size exclusion limits displayed by the L6 deletion mutant porins, suggest that loop L6 folds back into the beta-barrel thereby constricting the native FomA channel . Thus, the position of the channel constriction loop appears to be shifted towards the C terminus in the FomA porin, as compared to the crystal structures of five non-specific diffusion porins.

Int J Hyg Environ Health, 2001 Mar, 203(3), 205 - 13
Prevalence and growth of pathogens on salad vegetables, fruits and sprouts; Viswanathan P et al.; A total of 120 samples, comprising different types of raw vegetables (seven), fruits (three) and sprouts (three) obtained from street vendors, were tested for aerobic plate count, coliform count and various food-borne pathogens . Average aerobic plate counts for salad vegetables, fruits and sprouts were greater than 10(10) cfu/g and 10(9) cfu/g respectively . Pathogens isolated were S . aureus, E . coli, Enterobacter sp., Klebsiella sp., S . typhi, Serratia sp., Providencia sp . and P . aeruginosa . The antibiotic resistant patterns of the isolates revealed P . aeruginosa to be the most antibiotic resistant, E . coli, Salmonella, Enterobacter and P . aeruginosa also showed the presence of plasmids . The model development phase of this study involved 27 growth curves conducted under 9 combinations of temperature and pH in the Brain Heart Infusion Broth . Models for specific growth rate and lag period were developed by response surface modelling using multiple linear regression analysis . The model provides an estimate of bacterial growth in response to any combination of the variables studied within specified ranges . Growth patterns of organisms on vegetable and fruits were also studied at room temperature (32 degrees C) to assess the growth in the actual food environment . Cucumber and watermelon supports the growth of S . aureus and S . typhi, carrot retarded their growth while pineapple did not support the growth.

Biochimie, 2001 Feb, 83(2), 219 - 29
Roles of Escherichia coli histone-like protein HU in DNA replication: HU-beta suppresses the thermosensitivity of dnaA46ts; Bahloul A et al.; The HU protein is a small, basic, heat-stable DNA-binding protein that is well-conserved in prokaryotes and is associated with the bacterial nucleoid . In enterobacteria, including Escherichia coli, HU is a heterotypic dimer, HUalphabeta, composed of two closely related sub-units encoded by the hupA and hupB genes, respectively . HU was shown to participate in vitro in the initiation of DNA replication as an accessory factor to assist the action of DnaA protein in the unwinding of oriC DNA . To further elucidate the role of HU in the regulation of the DNA replication initiation process, we tested the synchrony phenotype in the absence of either one or both HU sub-units . The hupAB mutant exhibits an asynchronous initiation, the hupA mutant shows a similar reduced synchrony, whereas the hupB mutant shows a normal phenotype . Using a thermosensitive dnaA46 strain (dnaA46ts), an initiation mutant, we reveal a special role of HUbeta . The presence of a plasmid overproducing HUbeta in a dnaA46ts lacking HU (hupAB background) compensates for the thermosensitivity of this initiation mutant . Moreover, the overproduction of HUbeta confers to dnaA46ts a pattern of asynchrony similar to that of a dnaAcos, the intragenic suppressor of dnaA46ts . We show that the relative ratio of HUalpha versus HUbeta is greatly perturbed in dnaA46ts which accumulates little, if any, HUbeta . Therefore, the suppression of thermosensitivity in dnaA46hupAB by HUbeta may be caused by an unexpected absence of HUbeta in the dnaA46ts mutant . Visibly the HU composition is sensitive to the different states of DnaA, and may play a role during the regulation of the initiation process of the DNA replication by affecting subsequent events along the cell cycle.

J Invertebr Pathol, 2001 Feb, 77(2), 120 - 8
The association of Western flower thrips, Frankliniella occidentalis, with a near Erwinia species gut bacteria: transient or permanent?
de Vries EJ, Breeuwer JA, Jacobs G, Mollema C.
Associations between insects and gut bacteria are ubiquitous . It is possible to make a distinction between permanent associations (called symbiosis), in which the same type of bacteria is present in more than one generation of the insect, and transient associations . Transient bacteria are ingested together with food but do not settle in the insect gut in such a way that they will be passed on to the next generation . In this study, we describe the permanent association between Western flower thrips (Frankliniella occidentalis), a polyphagous insect species that is a major pest worldwide, and one type of gut bacteria . On the basis of direct microscopic observations and counts of bacteria, it was found that thrips from the populations studied contained large numbers of bacteria in their hindgut . Bacteria were isolated from their host and grown on 10 different agar media . The number of bacteria isolated on agar media equaled the number of direct counts . All isolates had the same colony morphology . On the basis of their 16S rDNA sequence these bacteria were identified as Enterobacteriaceae, closely related to Escherichia coli . Isolates tested with API 20E biochemical tests were Erwinia species . This was the only type of bacteria found in all thrips individuals on any of the 10 different agar media . Universal primers, which would potentially pick up DNA from any bacterium present in the insect, were applied on crude DNA extracts from thrips with bacteria . We only found 16S rDNA sequences similar to those of the isolated thrips gut bacteria . The same type of bacteria was present in all life stages of the thrips and was found to persist in the thrips populations for at least 2 years (more than 50 generations) .

J Assoc Physicians India, 1998 May, 46(5), 445 - 7
Central venous catheter related infections in a tertiary care hospital; Verghese SL et al.; Intravascular catheters are increasingly important causes of nosocomial infections . Catheter related complications range from local exit site or tunnel infections to frank bacteremias . A semiquantitative method of culture of central venous catheters (CVC) was done in our hospital from January to December 1996 . A total of 119 catheter tips sent to the Microbiology Department were cultured and 11 (9.24%) showed significant growth with associated blood stream infection . 14 (11.76%) of the CVCs showed scanty or less than 15 colonies in roll or contents and there was no associated blood stream infection . 7 (5.88%) showed moderate to heavy growth in roll and contents and there was no blood stream infection . The age groups ranged from 2 months to 66 years . The results of the study indicate that Gram negative organisms formed the predominant isolates . Gram negative isolates included Klebsiella species, Enterobacter species, E . coli species, Serratia and non-fermenting Gram negative bacilli . Coagulase negative staphylococcus which is often believed to be an important pathogen was not associated with bacteremia or septicemia in our hospital, during this study period . Considering the fact that 1553 operations were performed during the study period, the infection rate through CVC's would work out to a negligible 0.71%.

Planta Med, 2001 Feb, 67(1), 3 - 12
Inhibitors of bacterial topoisomerases: mechanisms of action and resistance and clinical aspects; Heisig P; The quinolone class of inhibitors of bacterial type II topoisomerases has gained major clinical importance during the last years due to improvements in both pharmacokinetic and pharmacodynamic properties . These include favorable bioavailability allowing oral administration, good tolerability, high tissue concentrations as well as superior bactericidal activity against a broad spectrum of clinically relevant pathogens, like enterobacteria, Pseudomonas aeruginoso, Staphylococcus aureus, and Streptococcus pneumoniae . In addition, no enzymatic mechanism of drug inactivation exists in bacteria and no indications for transfer of clinically relevant resistance exist . Nevertheless, resistance is being increasingly reported, even for naturally highly susceptible species like Escherichia coli . The underlying mechanisms of resistance include alterations in both bacterial targets, DNA gyrase and topoisomerase IV, often combined with mutations affecting drug accumulation, e.g., by increased drug efflux, reduced drug influx, or both . Investigations aiming at understanding the molecular mechanisms of quinolone action and resistance in more detail should provide a basis for a rational design of more potent derivatives . In addition, a prudent use of these highly valuable "magic bullets" is necessary to preserve their potential for the future.

Phytother Res, 2001 Mar, 15(2), 139 - 41
Antimicrobial activity of honokiol and magnolol isolated from Magnolia officinalis; Ho KY et al.; The antimicrobial activity of honokiol and magnolol, the main constituents of Magnolia officinalis was investigated . The antimicrobial activity was assayed by the agar dilution method using brain heart infusion medium and the minimum inhibitory concentration (MIC) were determined for each compound using a twofold serial dilution assay . The results showed that honokiol and magnolol have a marked antimicrobial effect (MIC = 25 microg/mL) against Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Micrococcus luteus and Bacillus subtilis, but did not show antimicrobial activity (MIC > or = 100 microg/mL) for Shigella flexneii, Staphylococcus epidermidis, Enterobacter aerogenes, Proteus vulgaris, Escherichia coli and Pseudomonas aeruginosa . Our results indicate that honokiol and magnolol, although less potent than tetracycline, show a significant antimicrobial activity for periodontal pathogens . Hence we suggest that honokiol and magnolol might have the potential to be an adjunct in the treatment of periodontitis .

FEMS Microbiol Lett, 2001 Mar 15, 196(2), 147 - 51
Enterobactin: the characteristic catecholate siderophore of Enterobacteriaceae is produced by Streptomyces species.(1); Fiedler HP et al.; Enterobactin is described in the literature as the typical iron-chelating compound (siderophore) produced by bacteria of the family Enterobacteriaceae . In the course of a HPLC with diode array detection screening programme for detection of novel secondary metabolites, enterobactin, its biosynthetic precursor 2,3-dihydroxy-N-benzoylserine and its linear dimer and trimer condensation products were found to be produced by two Streptomyces strains besides the trihydroxamate-type siderophores desferri-ferrioxamine B and E.

MMWR Morb Mortal Wkly Rep, 2000 Jan 7, 48(51-52), 1167 - 71
Laboratory capacity to detect antimicrobial resistance, 1998; Release of complement regulatory proteins from ocular surface cells in infections; Institute of Pathology, Case Western Reserve University, Cleveland, Ohio 44106, USAPURPOSE: The decay accelerating factor (DAF or CD55) and the membrane inhibitor of reactive lysis (MIRL or CD59), two complement regulatory proteins that protect self cells from autologous complement-mediated injury, are attached to corneal and cqonjunctival epithelial cells by glycosylphos-phatidylinositol (GPI) anchors . We sought to 1) determine the frequency with which bacteria recovered from patients with infections of the eye elaborate factors that can remove these surface proteins from ocular cells, 2) determine the spectrum of bacteria from other sites that have similar effects, and 3) establish the time interval required for reconstitution of the two regulators . METHODS: Culture supernatants of 18 ocular isolates {P . aeruginosa (n = 3), S . marcescens (n = 1), S . epidermidis (n = 9), and S . aureus (n = 5)}, and > 100 other clinical specimens isolated in the hospital's microbiology laboratory {P . mirabilis (n = 1), S . aureus (n = 65), S . epidermidis (n = 24), B . cereus (n = 12), H . influenzae (n = 15), and Enterobacter sp . (n = 21)} were incubated at 37 degrees C for various times with conjunctival epithelial cells, conjunctival fibroblasts or HeLa cells and the release of DAF and CD59 proteins from the surfaces of the cells analyzed by 2-site immunoradiometric assays and by Western blotting . The kinetics of recovery of DAF and CD59 expression on the cells was measured by flow cytometry . RESULTS: DAF and/or CD59 release from the cell monolayers varied from < 5% to > 99% at as much as a 1:81 dilution of the supernatant from some bacteria . On conjunctival epithelial cells, more than 8 hr was required for 44% recovery of DAF expression and for 50% recovery of CD59 expression . CONCLUSIONS: Bacteria produce phospholipases and/or other enzymes which can efficiently remove DAF and CD59 from ocular cell surfaces . This phenomenon may correlate with their in vivo pathogenicity.

Can J Microbiol, 2001 Feb, 47(2), 110 - 7
Isolation and 16S rRNA sequence analysis of the beneficial bacteria from the rhizosphere of rice; Mehnaz S et al.; The present study deals with the isolation of plant growth promoting rhizobacteria (PGPR) from rice (variety NIAB IRRI-9) and the beneficial effects of these inoculants on two Basmati rice varieties . Nitrogen-fixing activity (acetylene-reduction activity) was detected in the roots and submerged shoots of field-grown rice variety NIAB IRRI-9 . Estimation of the population size of diazotrophic bacteria by ARA-based MPN (acetylene reduction assay-based most probable number) in roots and shoots indicated about 10(5)-10(6) counts/g dry weight at panicle initiation and grain filling stages . Four bacterial isolates from rice roots and shoots were obtained in pure culture which produced phytohormone indoleacetic acid (IAA) in the growth medium . Among these, three isolates S1, S4, and R3 reduced acetylene to ethylene in nitrogen-free semi-solid medium . Morphological and physiological characteristics of the isolates indicated that three nitrogen-fixing isolates S1, S4, and R3 belonged to the genus Enterobacter, while the non-fixing isolate R8 belonged to the genus Aeromonas . 16S rRNA sequence of one isolate from root (R8) and one isolate from shoot (S1) was obtained which confirmed identification of the isolates as Aeromonas veronii and Enterobacter cloacae, respectively . The 1517-nucleotide-long sequence of the isolate R8 showed 99% similarity with Aeromonas veronii (accession No . AF099023) while partial 16S rRNA sequence (two stretches of total 1271 nucleotide length) of S1 showed 97% similarity with the sequence of Enterobacter cloacae (accession No . AJ251469) . The seedlings of two rice varieties Basmati 385 and Super Basmati were inoculated with the four bacterial isolates from rice and one Azospirillum brasilense strain Wb3, which was isolated from wheat . In the rice variety Basmati 385, maximum increase in root area and plant biomass was obtained in plants inoculated with Enterobacter S1 and Azospirillum Wb3, whereas in the rice variety Super Basmati, inoculation with Enterobacter R3 resulted in maximum increase of root area and plant biomass . Nitrogen fixation was quantified by using 15N isotopic dilution method . Maximum fixation was observed in Basmati 385 with the inoculants Azospirillum Wb3 and Enterobacter S1 where nearly 46% and 41% of the nitrogen was derived from atmosphere (%Ndfa), respectively . In general, higher nitrogen fixation was observed in variety Basmati 385 than in Super Basmati, and different bacterial strains were found more effective as inoculants for the rice varieties Basmati 385 and Super Basmati.

Int J Environ Health Res, 2001 Mar, 11(1), 95 - 105
Bacteriological profile and holding temperatures of street-vended foods from Addis Ababa; Muleta D et al.; A total of 150 samples of street foods comprising 30 each of 'sambussa', 'macaroni', 'lentil sandwich', 'kitfo' (raw minced meat) and 'egg sandwich' were examined for the relation between their holding temperatures and bacteriological profile . Over 90% of the samples were stored within a temperature range of 15.5-34.5 degrees C . At this holding temperature counts of coliforms and members of the Enterobacteriaceae were below detectable levels in 'sambussa' samples . In 'macaroni', 'lentil sandwich', 'kitfo' and 'egg sandwich' these counts were higher than 10(6) cfu g(-1) in most cases . Over 70% of the street food samples had aerobic mesophilic counts higher than 10(7) cfu g(-1) . Of the total of 1552 bacterial strains isolated from the different food samples, Bacillus spp . (29.1%), staphylococci (22.8%) and micrococci (15.4%) were among the dominant groups . Members of the family Enterobacteriaceae (14.5%) were also frequently encountered.

Int J Environ Health Res, 2000 Dec, 10(4), 291 - 9
Use of norfloxacin in poultry production in the eastern province of Saudi Arabia and its possible impact on public health; Al-Mustafa ZH et al.; Samples of market-ready chicken muscle and liver from 32 local broiler farms were first screened for antibiotic residues by microbiological assay . The antibiotic-residue-positive muscles and livers from 22 farms were further analysed for norfloxacin (NFX) residues by high performance liquid chromatography . NFX was detected in 35.0% and 56.7% of raw antibiotic-residue-positive muscles and livers, respectively . The NFX-positive muscles and livers were respectively obtained from 11 (50.0%) and 14 (63.6%) of the 22 antibiotic-residue-positive farms . Since the maximum residue limit (MRL) for NFX has not yet been fixed, the MRL for enrofloxacin was used in the study . All NFX-positive farms had mean raw tissue levels, which were 2.7- to 34.3-fold higher than the MRL . Although cooking markedly reduced NFX tissue concentrations, mean detectable levels remained above MRL in large proportions of NFX-positive samples and farms . Susceptibility patterns of Enterobacteriaceae isolates from chicken and human patients to NFX showed alarmingly high rates of resistance in chicken isolates especially among Escherichia coli (45.9%) and Pseudomonas spp . (70.6%) compared with patients' isolates (10.5% and 18.2%, respectively) . The study reveals widespread misuse of NFX in the local poultry industry, which may pose a major risk to public health including possible stimulation of bacterial resistance and hypersensitivity reactions to fluoroquinolones . More prudent use of fluoroquinolones in food-producing animals is therefore recommended . Further, there is a need to establish MRL values for NFX.

Mol Microbiol, 2001 Mar, 39(6), 1533 - 45
Identification of a non-haem catalase in Salmonella and its regulation by RpoS (sigmaS); Robbe-Saule V et al.; We report the identification and functional analysis of katN, a gene encoding a non-haem catalase of Salmonella enterica serotype Typhimurium . katN, which is not present in Escherichia coli, is located between the yciGFE and yciD E . coli homologues in the Salmonella genome . Its predicted protein product has a molecular weight of 31 826 Da and is similar to the Mn-catalases of Lactobacillus plantarum and Thermus spp . Its product, KatN, was visualized as a 37 kDa protein in E . coli maxicells . A KatN recombinant protein, containing six histidine residues at its C-terminus, was purified, and its catalase activity was observed on a non-denaturing polyacrylamide gel . KatN was also visualized by catalase activity gel staining of bacterial cell extracts . Its expression was shown to be regulated by growth phase and rpoS . Northern blotting indicated that kat forms an operon with the upstream yciGFE genes . A putative rpoS-regulated promoter was identified upstream of yciG . Southern blotting revealed that katN is conserved within Salmonella serovars . katN homologues were found in Pseudomonas aeruginosa, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae and Serratia marcescens . A katN mutation did not appear to affect the hydrogen peroxide (H2O2) response of Salmonella . However, the expression of katN increased the H2O2 resistance of unadapted cells in the exponential phase and of rpoS mutants in stationary phase . Thus, KatN may contribute to hydrogen peroxide resistance in Salmonella in certain environmental conditions.

FEMS Microbiol Lett, 2001 Mar 1, 196(1), 1 - 6
Epigenetic regulation of carnitine metabolising enzymes in Proteus sp . under aerobic conditions; Engemann C et al.; Proteus sp . is able to catalyse the reversible transformation of crotonobetaine into L(-)-carnitine during aerobic growth . Contrary to other Enterobacteriaceae no reduction of crotonobetaine into gamma-butyrobetaine could be detected in the culture supernatants . Activities of L(-)-carnitine dehydratase, carnitine racemasing system and crotonobetaine reductase could be determined enzymatically in cell-free extracts of Proteus sp . Small amounts of gamma-butyrobetaine were found in cell-free extracts, indicating that it accumulates in the cell and inhibits the crotonobetaine reductase . Crotonobetaine and L(-)-carnitine were able to induce enzymes of carnitine metabolism . gamma-Butyrobetaine and glucose repress carnitine metabolism in Proteus sp . Other betaines are neither inducers nor repressors . Monoclonal antibodies against purified CaiA from Escherichia coli O44K74 recognise an analogous protein in cell-free extract of Proteus sp . No cross-reactivity could be detected with monoclonal antibodies against purified CaiB and CaiD from E . coli O44K74.

Antimicrob Agents Chemother, 2001 Apr, 45(4), 1022 - 9
Rapid screening technique for class 1 integrons in Enterobacteriaceae and nonfermenting gram-negative bacteria and its use in molecular epidemiology; Maguire AJ et al.; A screening technique for integrons in members of the family Enterobacteriaceae and nonfermenting gram-negative bacteria by real-time PCR is reported . A total of 226 isolates of gram-negative bacteria obtained from a variety of clinical specimens were screened for class 1 integrons by real-time PCR performed on a LightCycler instrument . This technique used a primer pair specific for a 300-bp conserved region at the 5' ends of class 1 integrons . The screening assay was evaluated by comparison with results obtained by the conventional, thermal-block PCR (long PCR) by using established conditions and primers for the detection of class 1 integrons, and the real-time PCR technique was thus shown to be both sensitive and specific . DNA from 50 of 226 (22%) isolates screened was identified as containing an integron by the screening PCR, and sequence data were obtained across the integron for 34 of 50 (68%) of these isolates . In an attempt to study the molecular epidemiology of antimicrobial resistance genes carried within integrons, a comparison of the types of gene cassettes carried by isolates from different patients was made . Adenyltransferase genes conferring resistance to streptomycin and spectinomycin were the predominant gene cassettes amplified in the study . Resistance to trimethoprim was also frequently found to be encoded within integrons . Furthermore, multiple bacterial isolates obtained from one patient over a 5-month period were all shown to carry an integron containing the same single adenyltransferase gene cassette, suggesting that these elements were relatively stable in this case.

Infect Immun, 2001 Apr, 69(4), 2493 - 501
Identification of stress-responsive genes in Streptococcus mutans by differential display reverse transcription-PCR; Chia JS et al.; Streptococcus mutans, which causes dental caries in the human oral cavity and occasionally causes infective endocarditis in the heart, withstands adverse environmental stress through diverse alterations in protein synthesis . Differential gene expression in response to environmental stress was analyzed by RNA fingerprinting using arbitrarily primed PCR with a panel of 11mer primers designed for differential display in Enterobacteriaceae . Dot and Northern blot hybridization confirmed that the transcription of several genes was up- or down-regulated following exposure to acid shock from pH 7.5 to 5.5 . RNA of a gene designated AP-185 (acid-stress protein) was induced specifically by acid treatment, while RNA of GSP-781 (general-stress protein) was up-regulated significantly when bacteria were exposed to high osmolarity and temperature, as well as low pH . The deduced amino acid sequence of AP-185 shares homology (78% identity) with branched-chain amino acid aminotransferase . Cloning and sequence analysis of GSP-781 revealed a potential secreted protein of a molecular mass of about 43 kDa and with a pI predicted to be 5.5 . Transcriptional levels of another gene, designated AR-186 (acid-repressed protein), which encodes putative aconitase, were repressed by acid treatment but were enhanced by plasma or serum components . Analogous results were identified in icd and citZ genes, and repression of these genes, along with AR-186, was also observed when they were exposed to high osmolarity and temperature . These results indicate that differential regulation of specific genes at the transcriptional level is triggered by different stress and that genes responsible for glutamate biosynthesis in the citrate pathway are coordinately regulated during the stress response of S . mutans.

Int J Food Microbiol, 2001 Feb 28, 64(1-2), 167 - 74
Cresol red thallium acetate sucrose inulin (CTSI) agar for the selective recovery of Carnobacterium spp; Wasney MA et al.; Carnobacterium spp . are commonly isolated from a variety of foods, especially from meats stored under anaerobic atmospheres at refrigeration temperatures, but the role of these organisms in the spoilage of meat and meat products is yet to be determined . Cresol Red Thallium Acetate Sucrose (CTAS) agar was developed as a selective medium for enumeration of carnobacteria, however problems such as poor recovery of Carnobacterium spp . and interference by other microorganisms have precluded its general use . The aim of this study was to improve CTAS agar by broadening its spectrum of selective recovery for carnobacteria while restricting the ability of interfering species to grow . Ten Carnobacterium spp . (five ATCC cultures and five isolates from fresh pork) and 20 other genera were used in testing the agar . A wider range of Carnobacterium spp . recovery was obtained by modifying concentrations of sucrose, manganese sulphate and thallium acetate . Additions of inulin and thiamine hydrochloride also improved growth response . The additions of vancomycin and Chrisin (nisin) eliminated interference from other microorganisms . A two-temperature incubation procedure was included to improve the characteristic growth of Carnobacterium spp . on the modified medium, identified as Cresol Red Thallium Sucrose Inulin (CTSI) agar . Lactic acid bacteria and Enterobacteriaceae were unable to grow on CTSI incubated aerobically . Growth of Carnobacterium spp . on CTSI yielded pink colonies, except for Cb . mobile, which formed gray colonies . In some instances, a red precipitate formed in the center of the colony . Yellowing and clearing of the growth medium was also frequently observed . Recovery of carnobacteria using CTSI was identical to that obtained with All Purpose Tween (APT) agar.

Int J Food Microbiol, 2001 Feb 28, 64(1-2), 1 - 11
PCR primers designed from malic acid dehydrogenase gene and their use for detection of Escherichia coli in water and milk samples; Hsu SC et al.; Escherichia coli has been the appropriate focus for monitoring of potential enteric pathogens in water and foods . Although several methods have been used for the detection or enumeration of E . coli cells in water and foods, the time and accuracy limitations of these methods suggest the need of a rapid and specific method . By comparison of the gene sequences coding for malic acid dehydrogenase (mdh) of E . coli and non-E . coli strains, two oligonucleotides were designed and their possible use as E . coli-specific PCR primers was tested . All of the 110 E . coli strains tested, including non-pathogenic and various pathogenic strains, generated the expected PCR products with Mw equal to 392 bp . On the other hand, only 97 of these 110 E . coli strains were detectable using the BAM gas production method . With the exception of Shigella strains, non-E . coli strains, including strains of the family of Enterobacteriaceae, did not generate any false positive PCR results . When this PCR system was used for the monitoring of E . coli cells inoculated into water and milk samples, as low as 10(0) cfu per 100 ml of water or per ml of milk sample could be detected if an 8 h preculture step was performed prior to the PCR . Including the preculture step, the whole PCR detection process may be completed within 12 h.

Mol Ecol, 2001 Jan, 10(1), 217 - 28
Independent origins and horizontal transfer of bacterial symbionts of aphids; Sandstrom JP et al.; Many insect groups have obligate associations with primary endosymbionts: mutualistic bacteria that are maternally transmitted and derived from an ancient infection . Often, the same insects are hosts to 'secondary' bacterial symbionts which are maternally transmitted but relatively labile within host lineages . To explore the dynamics of secondary symbiont associations in aphids, we characterized bacteria infecting 15 species of macrosiphine aphids using DNA sequencing, diagnostic polymerase chain reaction (PCR), diagnostic restriction digests, phylogenetic analyses, and electron microscopy to examine aphids from nature and from laboratory colonies . Three types of bacteria besides Buchnera were found repeatedly; all three fall within the Enterobacteriaceae . The R-type has a 16S rDNA less than 0.1% different from that of the secondary symbiont previously reported from Acyrthosiphon pisum and is related to Serratia species . The T-type includes a symbiont previously reported from a whitefly; the U-type comprises a new cluster near the T-type . The T-type was found in every one of 40 Uroleucon ambrosiae clones collected throughout the United States . In contrast, A . pisum individuals were infected by any combination of the three symbiont types . Secondary symbionts were maternally transmitted for 11 months within laboratory-reared A . pisum clones and were present in sexually produced eggs . PCR screens for a bacteriophage, APSE-1, indicated its presence in both A . pisum and U . ambrosiae containing secondary symbionts . Electron microscopy of R-type and T-type bacteria in A . pisum and in U . ambrosiae revealed rod-shaped organisms that attain extremely high densities within a few bacteriocytes.

Diagn Microbiol Infect Dis, 2001 Feb, 39(2), 125 - 7
Carbapenem-resistant Serratia marcescens isolates producing Bush group 2f beta-lactamase (SME-1) in the United States: results from the MYSTIC Programme; Gales AC et al.; Two carbapenem (imipenem, meropenem)-resistant Serratia marcescens strains were isolated in the United States (Chicago, IL) through the 1999 MYSTIC (Meropenem Yearly Susceptibility Test Information Collection) Programme . The S . marcescens antimicrobial susceptible patterns were: susceptible to ceftriaxone, ceftazidime, and cefepime (MICs, < or = 0.25 microg/ml), and resistance to the carbapenems (imipenem and meropenem; MIC, > 32 microg/ml) and aztreonam (MIC, > = 16 microg/ml) . Each S . marcescens isolate shared an identical epidemiologic type (ribotype and PFGE) and the outer membrane protein profile was also identical to those of the wild type susceptible strains from the same medical center . The PCR utilizing bla(sme-1) primers amplified a gene product that was identified as consistent with SME-1 after DNA sequencing . Imipenem and meropenem resistance due to production of carbapenem-hydrolyzing enzymes among clinical isolates is still very rare, but microbiology laboratories should be aware of these chromosomally encoded enzymes among class C beta-lactamases producing enteric bacilli such as S . marcescens and Enterobacter cloacae.

Diagn Microbiol Infect Dis, 2001 Feb, 39(2), 105 - 16
Antibacterial activity of 41 antimicrobials tested against over 2773 bacterial isolates from hospitalized patients with pneumonia: I--results from the SENTRY Antimicrobial Surveillance Program (North America, 1998); Mathai D et al.; Pneumonia is the second most frequent cause of nosocomial infection, and hospitalization frequently is needed for community-acquired pneumonia . Knowledge of causative pathogens through periodic surveillance, and their prevailing antimicrobial susceptibility patterns becomes paramount in choosing appropriate empiric therapy . The SENTRY Antimicrobial Surveillance Program, tracks pathogen distribution worldwide since 1997 and documents emerging resistance to a wide range of antimicrobial agents . During the respiratory disease season in 1998, each of 30 medical centers (25 in the United States {US}, and five in Canada {CAN}) contributed 100 consecutive isolates obtained from hospitalized patients with suspected pneumonia . The 2773 organisms, processed by the monitor consisted of a total of 35 species, with Staphylococcus aureus comprising 25.6% of all isolates and five other species (Pseudomonas aeruginosa 18.7%, Haemophilus influenzae 9.4%, Streptococcus pneumoniae 7.8%, Klebsiella spp . 7.0%, and Enterobacter spp . 6.7%) making up almost 50% of the total . In the US, pneumococci (8.5%) were more prevalent than in CAN (4.1%; p = 0.001) . The US isolates of S . pneumoniae were variably susceptible to penicillin (76.8%), with non-susceptible strains demonstrating greater levels of cross resistance to macrolides (31.8%), cefepime (9.0%) and cefotaxime (6.8%), but remaining susceptible to gatifloxacin and quinupristin/dalfopristin . H . influenzae and Moraxella catarrhalis were generally ampicillin-resistant, 40.4-44.4% and 93.7-95.7%, respectively . P . aeruginosa remained very susceptible to amikacin (91.3-93.8%) > tobramycin > meropenem > piperacillin/tazobactam > gentamicin > piperacillin > cefepime (80.0-81.8%) . Extended spectrum beta-lactamase phenotypes among the Klebsiella spp . were isolated from five medical centers in the US and were 4.8-6.0% overall; a rate similar to the previous year . Among the US isolates of Enterobacter spp., only 77.6% and 79.6% were susceptible to ceftazidime and cefotaxime, respectively, but >90% were inhibited by cefepime, imipenem, meropenem, aminoglycosides, and fluoroquinolones . Isolates from CAN were generally more susceptible, except for Pseudomonas isolates, where resistance to aminoglycosides, fluoroquinolones and imipenem was greater . The SENTRY Program results outline important national differences in the frequencies of pathogen occurrence, but more importantly, identify unstable patterns of resistance to available antimicrobial drugs, and serves as a reference for results of other local, national or international investigations.

What Is Protein?, What Is Pcr?, What Is Staphylococcus Aureus?, What Is Bioengineering?, What Is Amino Acid?, s, Microbiology, a, Microbes, o, Bacteria, a, Bacterium, s, Microorganism, e, Salmonella typhimurium, n, Lactococci, i, Cholera, i, Microorganism, n, Micrococci, e, Antimicrobials, s, Streptococci, s, Cryptococci, n, Antibiotic prophylaxis, c, Antibiotics, n, Antibiotics, n, Antibiotics, i, Salmonella typhimurium, c, Fermentations, r, Halophilic bacterium, c, Cholera, o, Bifidobacterium, s, Escherichia coli, c, Multidrug resistant, o, Antibiotics, s, Antibiotics

Scientific Publications - Work Done by Microbiology Reader Bioscreen C
Agricultural Microbiology Anaerobic Microbiology Antimicrobial Susceptibility Artificial Atmosphere Bioassay of Antibiotics Biofilm Microbiology Bioreactor Technology Biotechnology Cell Biology Clinical Microbiology Environmental Microbiology Experiments with Yeast	Fermentation Food Microbiology Functional Genomics Gene Technology Growth Media Development Growth Rate and Lag Time Industrial Microbiology Medical/Pharmaceutical Field Microbiological Assay Microbiological Research Microbiology of Cosmetics go to a specific theme...	Military Microbiology Molecular Microbiology Mutagenicity and Genotoxicity Oral Microbiology Patents Postantibiotic Studies Soil Microbiology Spore Microbiology Veterinary Microbiology Waste/Wastewater Treatment Water Microbiology Wine Microbiology

� 2005 Transgalactic Ltd (manufacturer of Bioscreen C software) | Privacy Statement | P.O. Box 1393, 00101 Helsinki, Finland, phone: +358 9 85172920, fax: +358 9 8749481, e-mail: microbiology@bionewsonline.com

Last modified: May 25, 2005