Enterobacters

J AOAC Int, 2003 Jul-Aug, 86(4), 802 - 14
3M Petrifilm enterobacteriaceae count plate method for enumeration of enterobacteriaceae in selected foods: collaborative study; Silbernagel KM et al.; The practice of detecting and enumerating all oxidase-negative, glucose-fermenting-Gram-negative rods (i.e., the family Enterobacteriaceae) is used to indicate unsanitary or inadequate food processing conditions . The objective of this interlaboratory collaborative study was to evaluate and compare the methods described in Standard Methods for the Examination of Dairy Products (SMEDP) and the Compendium of Methods for the Microbiological Examination of Foods (Compendium) with a commercial product, the 3M Petrifilm Enterobacteriaceae Count Plate, for the recovery of Enterobacteriaceae in foods . Six foods--cheddar cheese, milk, flour, frozen prepared meals, frozen broccoli, and nut pieces--were analyzed for Enterobacteriaceae by 12 collaborating laboratories . For each food tested, the collaborators received 8 blind test portions consisting of a control test portion and 3 levels of inoculated test portion, each in duplicate . Each test portion was tested by the Petrifilm Enterobacteriaceae Count Plate method as well as the SMEDP or Compendium methods . The precision estimates (repeatability or within-laboratory variation, and reproducibility or between-laboratory variation) were calculated with standard statistical techniques.

Curr Microbiol, 2003 Aug, 47(2), 87 - 92
2-ketogluconic acid production and phosphate solubilization by Enterobacter intermedium; Hwangbo H et al.; Enterobacter intermedium, isolated from grass rhizosphere, exhibited a strong ability to solubilize insoluble phosphate . This bacterium oxidized glucose to gluconic acid and sequentially to 2-ketogluconic acid (2-KGA), which was identified using HPLC and GC-MS . The ability of E . intermedium to solubilize phosphate and produce 2-KGA produce in broth medium containing different components was monitored with air and without air supply . With an air supply, the production of 2-KGA markedly increased to about 110 g/l at day 10 in media containing 0.2 M gluconic acid, while it was about 65 g/l without gluconic acid addition . With an air supply, the concentration of soluble phosphate significantly decreased to 200-250 mg/l in media containing 1% CaCO3, whereas it was about 1000 mg/l without CaCO3 addition . Without an air supply, the concentration of 2-KGA and phosphate were negligible throughout the culture period.

Antimicrob Agents Chemother, 2003 Oct, 47(10), 3089 - 98
In vitro susceptibilities of gram-negative bacteria isolated from hospitalized patients in four European countries, Canada, and the United States in 2000-2001 to expanded-spectrum cephalosporins and comparator antimicrobials: implications for therapy; Wenzel RP et al.; Access to current antimicrobial agent surveillance data is an important prerequisite for the optimal management of patients with hospital-acquired infections . The present study used data collected in 2000 to 2001 from 670 laboratories in Europe (France, Germany, Italy, and Spain), Canada, and the United States to report on the in vitro activities of ceftriaxone, cefotaxime, and comparative agents against >125,000 isolates of gram-negative bacteria from hospitalized patients . All but two isolates of Enterobacteriaceae (one isolate of Proteus mirabilis from France and one isolate of Morganella morganii from Canada) were susceptible to imipenem . The susceptibility of Escherichia coli to ceftriaxone or cefotaxime was > or = 97% in each country, and for P . mirabilis, susceptibility was 99% in each country except Italy . In contrast, susceptibility of E . coli to ciprofloxacin varied from 80.5% (Spain) to 94.0% (France); levofloxacin susceptibility ranged from 75.2% (Spain) to 91.6% (United States) . Among Klebsiella pneumoniae and Klebsiella oxytoca isolates, ceftriaxone and cefotaxime susceptibilities ranged from 86.6 to 98.7% and 83.5 to 99.7%, respectively, depending upon the country . Considerable geographic variation in the susceptibilities (generally 85 to 95% susceptible) of Serratia marcescens and M . morganii to ceftriaxone and cefotaxime were observed . For S . marcescens, susceptibility to piperacillin-tazobactam varied from 81.5% (France) to 94.1% (Italy) and susceptibility to ciprofloxacin ranged from 66.2% (Germany) to 90.7% (Spain) . Enterobacter cloacae and Enterobacter aerogenes were less susceptible to ceftriaxone and cefotaxime than were the other species of Enterobacteriaceae studied . The present study demonstrated that established parenteral expanded-spectrum cephalosporin antimicrobial agents retain significant in vitro activity against many clinically important gram-negative pathogens.

Toxicon, 2003 Sep 15, 42(4), 359 - 66
Identification of Enterobacter bacteria as saxitoxin producers in cattle's rumen and surface water from Venezuelan Savannahs; Sevcik C et al.; We have previously shown that a paralytic toxin able to block sodium channels in nerve is associated with a cattle disease known as bovine paraplegic syndrome (BPS) {Toxicon . 31 (1993) 1581} . We have now identified this as saxitoxin (STX) using HPLC by either the methods of {Toxicon . 31 (1993) 1581}, or {Toxicon . 25 (1987) 1105} . In recent experiments we were able to collect and cultivate facultative anaerobic bacteria growing on rumen, grass and ponds of corrals with high incidence of BPS; the cultured bacteria produce compounds indistinguishable from STX under both HPLC procedures described above . Two species of the Enterobacter genus (E . asburiae and E . cloacae) and a strain of Klebsiella pneumoniae, were identified using standard biochemical criteria as well as gas chromatography of bacterial lipids . All these bacteria produced STX in aerobic cultures.

Chemotherapy, 2003 Sep, 49(5), 229 - 36
Beta-lactamase stability of faropenem; Dalhoff A et al.; Faropenem (FAR) is an orally available member of the penem class unique among carbapenems and other available beta-lactams . This study compared FAR to cephalosporins and imipenem with respect to beta-lactamase (BLA) stability and emergence of resistance to Staphylococcus aureus and Escherichia coli . BLA stability was studied using enzyme preparations from sonicated/centrifuged 24-hour cultures of E . coli, Enterobacter cloacae, Proteus vulgaris, Providencia rettgeri, Klebsiella pneumoniae, S . aureus, and Bacteroides fragilis grown in the presence of 20 mg/l ampicillin or cephaloridine to induce penicillinase or cephalosporinase, respectively . Substrate hydrolysis was quantitated spectrophotometrically . Multistep acquisition of resistance was promoted by growing bacteria in broth containing 2-fold dilutions of antibiotic over 10 cycles . Aliquots from test tubes with visible growth provided the inoculum for the next series of dilutions . FAR as well as other cephalosporins tested were highly stable to penicillinase derived from S . aureus and E . coli . However, E . coli- and P . vulgaris-derived cephalosporinase hydrolyzed cephaloridine, cefaclor and cefotiam considerably, whereas FAR was highly stable . FAR was highly stable against hydrolysis by various BLAs prepared from four B . fragilis strains and the rate of FAR hydrolysis by metallo-BLA was 5 times lower than that for imipenem . Additionally, the acquisition of resistant S . aureus strains was less pronounced for FAR compared to other agents tested . MICs rose 8-fold after the 10th sub-MIC exposure, while MICs rose 16-, 31- and 512-fold for cefixime, cefazolin and cefaclor, respectively . E . coli shifts in MICs were moderate for all the agents tested . In conclusion, FAR is characterized by pronounced BLA stability compared to other cephalosporins and imipenem . Furthermore, a lower propensity for resistance development with FAR as compared to cephalosporins was observed .

J Food Prot, 2003 Sep, 66(9), 1716 - 9
Effect of microorganism characteristics on leak size critical to predicting package sterility; Keller S et al.; The effects of microorganism size and motility on the leak size critical to the sterility of a package, along with the imposed pressure required to initiate liquid flow for the critical leak size, were measured . Pseudomonas fragi Lacy-1052, Bacillus atrophaeus ATCC 49337, and Enterobacter aerogenes ATCC 29007 were employed to assess package sterility . One hundred twenty-six 7-mm-long microtubes with interior diameters of 5, 10, and 20 microm were used to simulate package defects . Forty-two solid microtubes were used as controls . No significant differences were found between sizes or motility statuses of test organisms with respect to loss of sterility as a result of microbial ingress into test cells with microtube interior diameters of 5, 10, and 20 microm (P > 0.05) . Interactions between the initiation of liquid flow as a result of applied threshold pressures and sterility loss for test cells were significant (P < 0.05).

Ann Hematol, 2003 Oct, 82 Suppl 2, S167 - 74 Epub 2003 Sep 09.
Antimicrobial therapy of febrile complications after high-dose chemo-/radiotherapy and autologous hematopoietic stem cell transplantation--guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO); Bertz H et al.; Infectious complications occur in 60-100% of patients following high-dose chemotherapy (HDC) and autologous hematopoietic stem cell transplantation (HSCT), and are commonly caused by Gram-negative aerobic bacteria (such as Pseudomonas aeruginosa and enterobacteriacea e) and Gram-positive cocci (such as enterococci, streptococci and staphylococci), which should be covered by empiric first-line antibiotic therapy . Less frequently, infections are caused by fungi and anaerobic bacteria, and initial therapy does not necessarily have to cover coagulase-negative staphylococci, oxacillin-resistant S . aureus (MRSA), anaerobic bacteria and fungi . Patients who already receive antibiotics and develop pulmonary infiltrates should immediately be treated with systemic antifungals . Patients with fever and diarrhea or other signs and symptoms of gastrointestinal or perianal infection should be treated with antibiotics covering anaerobic bacteria and enterococci . Clinically stable patients with skin infections or central venous catheter-related infections can be treated with standard empiric antibiotic therapy including a beta-lactam active against Pseudomonas aeruginosa with or without an aminoglycoside, and should only receive glycopeptides if they do not respond to first-line therapy within 72 hours, become clinically unstable, have severe mucositis, or when resistance against the empiric antibiotics is demonstrated . Recombinant hematopoietic growth factors should not be added routinely but may be considered in life-threatening situations such as invasive pulmonary mycoses or sepsis.

Int J Antimicrob Agents, 2003 Sep, 22(3), 270 - 3
4-alkoxy and 4-thioalkoxyquinoline derivatives as chemosensitizers for the chloramphenicol-resistant clinical Enterobacter aerogenes 27 strain; Gallo S et al.; Enterobacter aerogenes is a Gram-negative bacteria frequently responsible for nosocomial respiratory tract infections . Strains resistant to chloramphenicol are frequently isolated . Alkoxy and thio-alkoxyquinolines have a potential to act as chemosensitizers that would render multi-drug-resistant (MDR) bacterial infections susceptible to antibiotics to which they were originally resistant . Several new quinoline derivatives have been prepared, characterized and studied for their ability to increase chloramphenicol sensitivity of E . aerogenes 27, a clinical strain that exhibits the MDR phenotype . Drugs investigated were either quinoline ethers or quinoline thio-ethers . Thio-ethers are much more efficient in increasing chloramphenicol sensitivity than other corresponding ethers . In particular, 4-piperidinoethylthio-quinoline increases the strain sensitivity to chloramphenicol by about 20 times at 2 mM concentration . Similarly, sensitivity to quinolone antibiotics dramatically increases . Because these quinoline derivatives act as inhibitors of the drug efflux pump responsible for bacterial resistance to chloramphenicol, they may serve as adjunct to conventional therapy of E . aerogenes infections.

Int J Antimicrob Agents, 2003 Sep, 22(3), 265 - 9
Thanatin activity on multidrug resistant clinical isolates of Enterobacter aerogenes and Klebsiella pneumoniae; Pages JM et al.; Efflux pumps protect bacterial cells by ejecting intracellular toxic molecules such as antibiotics, detergents and defensins that have penetrated the cell envelope . Some of these efflux pumps recognise structurally unrelated compounds (mdr pump) and account for the resistance of some organisms to two or more agents . It would be of interest to identify molecules that are able to circumvent the problems created by multidrug resistance phenotypes during antibiotic therapy . We have studied the activity of thanatin, a 21-residue cationic antimicrobial peptide produced by an insect, against three bacterial species . The antibacterial effect depended on the size of lipopolysaccharide side chains . In clinically resistant isolates of Enterobacter aerogenes and Klebsiella pneumoniae, the biological activity of thanatin is independent of the membrane permeability, possibly controlled by one or more porins, and/or the expression of drug efflux pumps, two mechanisms which confer high level antibiotic resistance . In addition, thanatin was able to improve the activity of structurally unrelated antibiotics (norfloxacin, chloramphenicol, tetracycline) on a multidrug- resistant E . aerogenes clinical isolate.

Eur J Intern Med, 2003 Aug, 14(5), 341 - 343
Infections in diabetic foot ulcers; Candel Gonzalez FJ et al.; Foot ulcers and infections are common in diabetic patients . A 30-month-long descriptive study was conducted in our hospital in which we analyzed microbiological isolates of all patients admitted with diabetic foot infections . The predominant flora identified were Staphylococcus aureus and coagulase-negative Staphylococcus, followed by Enterococcus spp., Streptococcus spp., and enterobacteriaceaes . In 27 positive cultures (42%) polymicrobial flora were found . There were only 5% anaerobic bacteria . There appears to be a relationship between the sample collection system and microbiological isolates.

J Biol Chem, 2003 Dec 5, 278(49), 49215 - 22 Epub 2003 Sep 16.
A new view of the mechanisms of UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) and 5-enolpyruvylshikimate-3-phosphate synthase (AroA) derived from X-ray structures of their tetrahedral reaction intermediate states; Eschenburg S et al.; UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) and 5-enolpyruvylshikimate-3-phosphate synthase (AroA) constitute the small enzyme family of enolpyruvyl transferases, which catalyze the chemically unusual reaction of enolpyruvyl transfer . MurA catalyzes the first step in the biosynthesis of the bacterial cell wall; AroA is the sixth enzyme of the shikimate pathway leading to the synthesis of aromatic compounds in numerous microorganisms and plants . Because both metabolic pathways are absent from mammals but essential for the growth of microorganisms, MurA and AroA are attractive targets for the development of novel antimicrobial drugs . We have determined the x-ray structures of the D305A mutant of Enterobacter cloacae MurA and the D313A mutant of Escherichia coli AroA, both of which crystallized in the presence of their substrates . The structures depict the tetrahedral reaction intermediate states of the enzymes and prove that, without the aspartate side chain, the overall addition-elimination reaction in both enzymes is halted after the addition step . The presented structures lead to a new view of the catalytic mechanism and, moreover, provide an ideal starting point for the rational design of potent inhibitors of MurA and AroA.

Rev Esp Quimioter, 2003 Jun, 16(2), 233 - 8
{Prevalence and susceptibility patterns of extended-spectrum betalactamase-producing Escherichia coli and Klebsiella pneumoniae in a general university hospital in Beirut, Lebanon}; Daoud Z et al.; Extended-spectrum betalactamases (ESBLs) are recognized worldwide as a problem in hospitalized patients . Their prevalence among clinical isolates of Enterobacteriaceae varies between countries and institutions . We studied the evolution of ESBL production by clinical isolates of Escherichia coli and Klebsiella pneumoniae and analyzed the patterns of susceptibility of these isolates to different antimicrobial agents in a general university hospital in Beirut . Of the 4299 isolates of E . coli and 1248 isolates of K . pneumoniae tested over the five years, 2.0% of the E . coli and 20.0% of K . pneumoniae were ESBL producing . A clear decrease in the susceptibility to all antibiotics was observed between 1999 and 2001, and no resistance to imipenem was detected . The isolates were distributed between the Intensive Care Unit (ICU), medical wards, outpatients, and other origins . The highest numbers were found in the ICU (E . coli 28.1% and K . pneumoniae 34.8%) . Three phenotypes of resistance to cefotaxime and ceftazidime were observed on the basis of microbiological results . The present study was the first to assess the occurrence and susceptibility patterns of extended-spectrum betalactamase-producing Enterobacteriaceae in Lebanon.

J Antimicrob Chemother, 2003 Oct, 52(4), 591 - 7 Epub 2003 Sep 12.
Evaluation of Oxoid combination discs for detection of extended-spectrum beta-lactamases; De Gheldre Y et al.; OBJECTIVES: We evaluated the reliability of cefpirome/clavulanate (CD04) compared with ceftazidime/clavulanate (CD02) and cefotaxime/clavulanate (CD03) Oxoid combination discs for the detection of extended-spectrum beta-lactamases (ESBL) in several Enterobacteriaceae isolates, including Enterobacter spp . METHODS: Overall, a total of 105 ESBL-positive {positive double-disc synergy test (DDST)} and 94 ESBL-negative (negative DDST) Gram-negative isolates were evaluated . Ninety-eight isolates were confirmed as ESBL-positive on the basis of the sequence alignments of the blaTEM and/or blaSHV gene amplification products, which matched with previously identified ESBLs . The phenotypic detection of ESBLs was performed by the three combination discs according to the NCCLS and BSAC methods . The CD04 disc was evaluated with the manufacturer's recommended zone size difference breakpoint of > or =4 mm . RESULTS: In Escherichia coli and Klebsiella spp., the sensitivities (%)/specificities (%) of CD02, CD03 and CD04 discs, and the combination of CD02 or CD04 discs, were, respectively, 88/92, 90/92, 95/84 and 100/82, while the corresponding figures were 94/100, 4/100, 94/100 and 100/100 in Enterobacter aerogenes . NCCLS and BSAC methods yielded concordant results in 99% of the isolates . CONCLUSIONS: CD04 and CD02 discs were the best combination for detection of ESBLs in our collection of Enterobacteriaceae isolates, including E . aerogenes.

Lett Appl Microbiol, 2003, 37(4), 275 - 80
The Yersinia HPI is present in Serratia liquefaciens isolated from meat; Olsson C et al.; AIMS: The aim of the study was to screen the Enterobacteriaceae flora of meat for the presence of bacteria harbouring the Yersinia high-pathogenicity island (HPI) . METHODS AND RESULTS: Bacteria from 29 meat and 29 liver samples were isolated on violet-red bile glucose agar . A total of 197 isolates were screened for the presence of the irp2 gene, encoded within the HPI, by PCR . One isolate that was positive for irp2 gene was also positive for the fyuA, irp1, ybtP/ybtQ, ybtX/ybtS and int/asn tRNA genes by PCR . The presence of fyuA, irp1 and irp2 genes was confirmed by Southern hybridization . CONCLUSIONS: The isolate was identified as Serratia liquefaciens by sequencing of the 16S rRNA gene and by ribotyping . SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of a Serratia harbouring the Yersinia HPI . Serratia is a frequently occurring Enterobacteriaceae genus in chill-stored meat.

J Appl Microbiol, 2003, 95(4), 744 - 52
Characterization of blaCMY-10 a novel, plasmid-encoded AmpC-type beta-lactamase gene in a clinical isolate of Enterobacter aerogenes; Lee SH et al.; AIMS: We report the description of a novel plasmid-encoded AmpC beta-lactamase gene (blaCMY-10) from Enterobacter aerogenes K9911729 that was isolated from a patient suffering from pneumonia in South Korea . METHODS AND RESULTS: Using antibiotic susceptibility testing, plasmid analysis, transconjugation and Southern blot analysis, the cefoxitin resistance phenotype reflects the presence of a large plasmid {pYMG-1 (130 kb)} in Ent . aerogenes K9911729 . One beta-lactamase with the pI of 8.0 from transconjugant of Ent . aerogenes K9911729 was identified by isoelectric focusing on a gel . A 1475 bp DNA fragment containing the blaCMY-10 gene, identified on pYMG-1 of Ent . aerogenes K9911729, was sequenced and an open reading frame coding for 382 amino acid, CMY-10, was found . The 37 class C beta-lactamases were subclassified into 1a to 1j and CMY-10 into 1a by phylogenetic analysis . A sequence identical to the common regions in In6, In7 and a novel integron from pSAL-1 was found upstream from blaCMY-10 gene at nucleotide 1-71 . CONCLUSIONS: These results clearly show that blaCMY-10 gene belongs to the group of ampC-related bla genes . Homology analysis among AmpC enzymes or ampC genes implied that integration of the chromosomal ampC gene into a large resident plasmid, followed by transconjugation, was involved in the evolution of blaCMY-10 gene . SIGNIFICANCE AND IMPACT OF THE STUDY: The first identification of the blaCMY-10 gene is of concern as chromosomal beta-lactamases may cause serious therapeutic problems if their genes are translocated onto plasmids.

J Appl Microbiol, 2003, 95(4), 664 - 76
Investigation of antibiotic and antibacterial agent cross-resistance in target bacteria from homes of antibacterial product users and nonusers; Cole EC et al.; AIM: To describe the relationship between antibiotic and antibacterial resistance in environmental and clinical bacteria from home environments across geographical locations, relative to the use or nonuse of antibacterial products, with a focus on target organisms recognized as potential human pathogens . METHODS AND RESULTS: In a randomized study, environmental and clinical samples were collected from the homes of antibacterial product users (n=30) and nonusers (n=30) for the isolation of target bacteria for antibiotic and antibacterial testing in three geographical areas (in USA and UK) . Isolates were tested for antibiotic susceptibility, with selected antibiotic-resistant and antibiotic-susceptible isolates tested against four common antibacterial agents (triclosan, para-chloro-meta-xylenol, pine oil and quaternary ammonium compound) . Prequalified users and nonusers at each location were randomly selected after meeting exclusionary criteria . Of 1238 isolates, more target bacteria were recovered from nonuser than user homes . Of Staphylococcus aureus isolates (n=33), none showed resistance to oxacillin or vancomycin; for Enterococcus sp . (n=149), none were resistant to ampicillin or vancomycin; and for Klebsiella pneumoniae (n=54)and Escherichia coli (n=24), none were resistant to third generation cephalosporins . Antibiotic resistance to one or more of the standard test panel drugs for Gram-positive and Gram-negative target bacteria was comparable between nonuser and user homes for both environmental and clinical isolates {e.g . resistance of environmental coagulase-negative (CN) Staphylococcus sp . was 73.8% (124/168) from nonuser homes and 73.0% (111/152) from user homes, and Enterobacteriaceae other than E . coli, 75.9% (186/245) from nonuser homes compared with 78.0% from user homes} . Of 524 Gram-negatives tested against preferred/alternative drugs, 97.1% (509/524) were susceptible to all antibiotics, across both groups . Isolates of S . aureus, Enterococcus sp . and CN Staphylococcus sp . susceptible to all preferred treatment drugs showed comparable antibacterial minimum inhibitory concentration (MIC) results between nonuser and user home isolates . For Gram-positives resistant to one or more preferred drugs, greatest resistance to antibacterial active ingredients was found in the nonuser group . For Gram-negatives, the antibacterial MIC data were comparable for isolates that were fully susceptible and resistant to one or more preferred/alternative treatment antibiotics . CONCLUSIONS: The results showed a lack of antibiotic and antibacterial agent cross-resistance in target bacteria from the homes of antibacterial product users and nonusers, as well as increased prevalence of potential pathogens in nonuser homes . SIGNIFICANCE AND IMPACT OF THE STUDY: It refutes widely publicized, yet unsupported, hypotheses that use of antibacterial products facilitates the development of antibiotic resistance in bacteria from the home environment.

J Anim Sci, 2003 Sep, 81(9), 2270 - 8
Nutritional evaluation of egg byproducts in diets for early-weaned pigs; Schmidt LS et al.; A total of 272 Cotswold pigs (17 +/- 1 d) were utilized in three experiments to evaluate the nutritive value of spray-dried egg proteins for early-weaned pigs . In all experiments, pigs were stratified by sex and initial BW and then assigned randomly to experimental diets . In Exp . 1, four corn-soybean meal-based diets containing 7% of either spray-dried porcine plasma (SDPP), spray-dried technical albumen (SDTA), SDTA stored at 70 degrees C for 3 d (SDTA-ht), or spray-dried whole egg (SDWE) were assigned to five pens each with four pigs for a 3-wk study period . Average daily gain, ADFI, and gain:feed ratio (G:F) were determined . At the end of wk 3, five pigs per treatment were killed to determine ileal AA and energy digestibilities, as well as Enterobacteriaceae counts . Compared with the SDPP diet, ADG and G:F were lower (P < 0.05) for SDTA-, SDTA-ht- and SDWE-containing diets . Apparent ileal digestibilities of cystine, histidine, isoleucine, methionine, and threonine in the SDPP diet were lower (P < 0.05) than in diets containing spray-dried egg products . Ileal digestible energy content did not differ (P > 0.05) in all diets (3.1 to 3.2 Mcal/kg) . Enterobacteriaceae counts were lower in the SDTA-ht diet than in either the SDTA or SDWE diets (P < 0.05) . In Exp . 2, the effect of substituting SDPP with varying levels of SDTA was investigated . Diets were randomly assigned to five pens (except for the 100% SDTA diet, which had four pens), each with four pigs . Average daily gain, ADFI, and G:F decreased linearly as the level of SDTA was increased in the diet (P < 0.05) . Replacing SDPP with SDTA at 25 or 50% had no effect on pig performance (P > 0.10) . In Exp . 3, phase I diets containing 0, 25, or 50% SDTA in place of SDPP (7% of the diet) were each assigned at random to eight pens each with four pigs for a 14-d period, after which all pigs were switched to a common phase II diet lacking both SDPP and SDTA for another 14 d . Average daily feed intake and ADG did not differ among all diets in phase I and II and overall (d 0 to 28) . Pigs fed the diet containing 50% SDTA in phase I had lower (P < 0.05) G:F than those fed the SDPP diet . The results indicate that technical albumen can replace 25 to 50% of SDPP in early-weaned pig diets without compromising performance, and further suggest that heat-treated SDTA may affect intestinal microbial population in pigs.

Diagn Microbiol Infect Dis, 2003 Sep, 47(1), 377 - 83
Contemporary re-evaluation of the activity and spectrum of grepafloxacin tested against isolates in the United States; Gordon KA et al.; Grepafloxacin potency and spectrum of activity were re-evaluated against contemporary pathogens collected from clinical infections in 2001-2002 . A total of 995 isolates were tested for grepafloxacin by the reference agar dilution method and these results were compared to those of 25 other antimicrobial agents . Grepafloxacin activity remained comparable to that of ciprofloxacin, levofloxacin and gatifloxacin against Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae (MIC(90), 0.03-2 microg/ml; 0.0-7.7% resistance rates) . For Pseudomonas aeruginosa, grepafloxacin was active against ciprofloxacin-susceptible (MIC(90), 2 microg/ml), but not against ciprofloxacin-resistant (MIC(90), >8 microg/ml) isolates . Against methicillin-susceptible Staphylococcus aureus, grepafloxacin susceptibility rate was 91.4%, equal to that of levofloxacin . None of the fluoroquinolones showed reasonable activity against methicillin-resistant staphylococci . Gatifloxacin and grepafloxacin had the same MIC(90) against beta-hemolytic streptococci (0.25 microg/ml) and penicillin-susceptible Streptococcus pneumoniae (0.25 microg/ml) . Grepafloxacin and other fluoroquinolone activities were not influenced by penicillin resistance in S . pneumoniae . Grepafloxacin was very active against Haemophilus influenzae (MIC(90), 0.03 microg/ml), Moraxella catarrhalis (MIC(90), 0.03 microg/ml) and Legionella spp . (MIC(90), 0.5 microg/ml) . These results on recently isolated organisms indicate that grepafloxacin has a sustained potency and spectrum against most clinically important and indicated pathogens.

Diagn Microbiol Infect Dis, 2003 Sep, 47(1), 361 - 4
Global patterns of susceptibility for 21 commonly utilized antimicrobial agents tested against 48,440 Enterobacteriaceae in the SENTRY Antimicrobial Surveillance Program (1997-2001); Sader HS et al.; A total of 48,440 Enterobacteriaceae isolates collected consecutively from patients hospitalized in participant SENTRY Antimicrobial Surveillance Program sites in four international regions (Asia-Pacific, Europe, Latin America, and North America) were tested by reference broth microdilution method against the most commonly used antimicrobial agents . The most active compounds could be divided in 3 groups based on their spectrum of activity . The first group included meropenem and imipenem, with 99.9% susceptibilty (S) rates for the Enterobacteriaceae . The second group includes amikacin (97.3% S) and cefepime (97.2% S); and a third active group had a rank order of susceptibility of: gatifloxacin = levofloxacin (91.7% S) > ceftazidime (91.4% S) > ceftriaxone (91.2% S) > aztreonam (91.1% S) > gentamicin (90.6% S) > piperacillin/tazobactam = ciprofloxacin (90.5% susceptibility) . These latter antimicrobial agents presented susceptibility rates of approximately 90% (89.8%-91.7%) . Continued resistance surveillance by various programs remain necessary to monitor the in vitro effectiveness of antimicrobial agents currently used in clinical practice.

Emerg Infect Dis, 2003 Aug, 9(8), 999 - 1002
NmcA carbapenem-hydrolyzing enzyme in Enterobacter cloacae in North America; Pottumarthy S et al.; An imipenem-resistant Enterobacter cloacae isolate was recovered from the blood of a patient with a hematologic malignancy . Analytical isoelectric focusing, inhibitor studies, hydrolysis, induction assays, and molecular sequencing methods confirmed the presence of a NmcA carbapenem-hydrolyzing enzyme . This first report of NmcA detected in North America warrants further investigation into its distribution and clinical impact.

Pharmazie, 2003 Aug, 58(8), 590 - 2
Stimulation of furanochromone accumulation in callus cultures of Ammi visnaga L . by addition of elicitors; Krolicka A et al.; In order to check the possibility of producing secondary metabolites, in vitro cultures of A . visnaga callus were established . The best growth of A . visnaga callus was obtained on Murashige and Skoog medium (MS) containing 6-benzyladenine (BA) and alpha-naphtaleneacetic acid (NAA) . The study was concentrated on the induction of production of secondary metabolites by exposing callus to abiotic elicitors: benzo(1,2,3)-thiadiazole-7-carbothionic acid S-methyl ester (BION) and a suspension of silica (SiO2) and biotic elicitors: autoclaved lysates of Enterobacter sakazaki and scleroglucan . GC analysis indicated that not-elicited callus of A . visnaga grown in darkness accumulated 2 times more visnagin than the one which was grown under a 16-h photoperiod . The highest accumulation of visnagin was observed in the callus culture elicited with scleroglucan or BION . Scleroglucan induced also the accumulation of khellin in A . visnaga callus . The presented work shows that biosynthesis of pharmacologically important secondary metabolites in A . visnaga cultures could be stimulated by application of elicitors.

Zh Mikrobiol Epidemiol Immunobiol, 2003 Jul-Aug, (4), 78 - 81
{Effect of gastrointestinal tract secretions on the anti-lysozyme activity of enterobacteria}; Tarasevich AV et al.; The effect of the duodenal contents and its components on the antilysozyme activity (ALA) of enterobacteria was studied . Under the action of native bile and the preparation of dried bile the stimulation of the expression of ALA factor in 86.6-93.3% of enterobacteria was observed . Pancreatin increased the level of the secretion of ALA factor by 50% in comparison with the control . The preparation of egg lysozyme produced no changes in the frequency and level of the expression of ALA factor . The study revealed the dose-dependant character of the action of duodenal contents: in the native form, as well as at concentrations of 50% and 25%, duodenal contents stimulated the expression of the ALA factor of enterobacteria; at concentrations of 12.5% and lower, its effect could be stimulating, inhibitory or neutral.

Zh Mikrobiol Epidemiol Immunobiol, 2003 Jul-Aug, (4), 23 - 7
{Molecular mechanisms of relationships between the host organism and pathogenic enterobacteria}; Tuigunov MM et al.; Modern data on the molecular mechanisms of relationships between the host organism and the pathogenic representatives of the family Enterobacteriaceae in the host-parasite system are presented . The process of cytokine and eicosanoid regulation of the immune process of the host in the norm and pathology states are analyzed . The examples of the mechanisms of immune suppression, false antigenic stimulation and the mimicry of pathogens are given.

Braz J Infect Dis, 2003 Apr, 7(2), 129 - 34
Plasmid-mediated extended-spectrum beta-lactamase-producing strains of Enterobacteriaceae isolated from diabetes foot infections in a Brazilian diabetic center; Motta RN et al.; We bacteriologically analyzed 156 species of Enterobacteriaceae, isolated from 138 patients with community-acquired diabetic foot ulcers, in a prospective study made at a diabetic center and at the Federal University of Ceara, Brazil, from March, 2000, to November, 2001.The samples were cultured using selective media, and identification, susceptibility tests and detection of plasmid-mediated-extended-spectrum-beta-lactamase (ESBL) producing strains were made with conventional and automated methods . The most frequently occurring pathogens were K . pneumoniae (21.2%), Morganella morganii (19.9%) and E . coli (15.4%) . High resistance rates were noted for ampicillin, first generation cephalosporin, trimethoprim/sulfamethoxazole, tetracycline, amoxicillin-clavulanic acid and chloramphenicol . ESBL-producing strains were detected in 6% of the patients . Resistance among gram-negative bacteria has become increasingly common, even in community-acquired infections.

Microb Drug Resist, 2003 Fall, 9(3), 299 - 305
Outbreak of TEM-24-producing Enterobacter aerogenes in a Spanish hospital; Salso S et al.; Organisms encoding multidrug resistance genes are becoming increasingly prevalent . During a 2-month period (December, 2000, to January, 2001), 83 consecutive isolates of Enterobacter spp . were collected in our microbiology department . Antibiotic susceptibility was determined using the Vitek II automatic system . We selected strains with decreased susceptibility to extended-spectrum cephalosporins . The double-disk potentiation test was positive in 10 of these strains, indicating the presence of extended-spectrum beta-lactamases (ESBLs) . Polymerase chain reaction (PCR), isoelectric focusing (IEF), and sequencing identified TEM 24 beta-lactamase in the 10 selected E . aerogenes . Random amplification of polymorphic DNA (RAPD-PCR) revealed the same clonal origin for all the strains tested and strongly suggest an outbreak of multidrug-resistant E . aerogenes . To follow up the trends in ESBLs-producing Enterobacter infections in the hospital over time, we repeated the study 1 year later (December, 2001, to February, 2002) . Only three ESBLs-producing Enterobacter were found . All of them corresponded to the previously characterized clone.

Pneumonol Alergol Pol, 2003, 71(1-2), 59 - 67
{Etiologic factors of pleural empyema as a potential source of nosocomial infections}; Jezierska-Anczukow A et al.; Pleural empyema still comprises an important therapeutic problem despite the availability of effective antibiotic therapy . This disorder is characterised by 20% mortality rate . Moreover, the involvement of multi-drug resistant bacterial strains may pose a risk of a nosocomial spread to other hospitalised patients . In the present study we have analysed 184 bacterial strains isolated from 63 patients with pleural empyema . A predominance of aerobic bacteria was detected, both Gram-positive cocci and Gram-negative bacilli . Staphylococci isolated from the clinical samples were characterised by a high percentage of strains resistant to gentamicin (86.3%) and methicillin (38.2%) . The other important etiological agents were Pseudomonas aeruginosa and Gram-negative enteric rods of the Enterobacteriaceae family . Only 1 strain of anaerobic bacteria was detected . The enteric bacilli were characterised by a low percentage of isolates susceptible to most of the tested antibiotics (< 60%), with an exception of ciprofloxacin (68%) and imipenem (100%) . These multi-drug resistant strains may spread nosocomially to other patients.

J Clin Microbiol, 2003 Sep, 41(9), 4264 - 9
Multiple CTX-M-type extended-spectrum beta-lactamases in nosocomial isolates of Enterobacteriaceae from a hospital in northern Italy; Pagani L et al.; Twelve isolates of Enterobacteriaceae (1 of Klebsiella pneumoniae, 8 of Escherichia coli, 1 of Proteus mirabilis, and 2 of Proteus vulgaris) classified as extended-spectrum beta-lactamase (ESBL) producers according to the ESBL screen flow application of the BD-Phoenix automatic system and for which the cefotaxime MICs were higher than those of ceftazidime were collected between January 2001 and July 2002 at the Laboratory of Clinical Microbiology of the San Matteo University Hospital of Pavia (northern Italy) . By PCR and sequencing, a CTX-M-type determinant was detected in six isolates, including three of E . coli (carrying bla(CTX-M-1)), two of P . vulgaris (carrying bla(CTX-M-2)), and one of K . pneumoniae (carrying bla(CTX-M-15)) . The three CTX-M-1-producing E . coli isolates were from different wards, and genotyping by pulsed-field gel electrophoresis (PFGE) revealed that they were clonally unrelated to each other . The two CTX-M-2-producing P . vulgaris isolates were from the same ward (although isolated several months apart), and PFGE analysis revealed probable clonal relatedness . The bla(CTX-M-1) and bla(CTX-M-2) determinants were transferable to E . coli by conjugation, while conjugative transfer of the bla(CTX-M-15) determinant from K . pneumoniae was not detectable . Present findings indicate that CTX-M enzymes of various types are present also in Italy and underscore that different CTX-M determinants can be found in a single hospital and can show different dissemination patterns . This is also the first report of CTX-M-2 in P . vulgaris.

Appl Environ Microbiol, 2003 Sep, 69(9), 5364 - 71
Morphological, host range, and genetic characterization of two coliphages; Goodridge L et al.; Two coliphages, AR1 and LG1, were characterized based on their morphological, host range, and genetic properties . Transmission electron microscopy showed that both phages belonged to the Myoviridae; phage particles of LG1 were smaller than those of AR1 and had an isometric head 68 nm in diameter and a complex contractile tail 111 nm in length . Transmission electron micrographs of AR1 showed phage particles consisting of an elongated isometric head of 103 by 74 nm and a complex contractile tail 116 nm in length . Both phages were extensively tested on many strains of Escherichia coli and other enterobacteria . The results showed that both phages could infect many serotypes of E . coli . Among the enterobacteria, Proteus mirabilis, Shigella dysenteriae, and two Salmonella strains were lysed by the phages . The genetic material of AR1 and LG1 was characterized . Phage LG1 had a genome size of 49.5 kb compared to 150 kb for AR1 . Restriction endonuclease analysis showed that several restriction enzymes could degrade DNA from both phages . The morphological, genome size, and restriction endonuclease similarities between AR1 and phage T4 were striking . Southern hybridizations showed that AR1 and T4 are genetically related . The wide host ranges of phages AR1 and LG1 suggest that they may be useful as biocontrol, therapeutic, or diagnostic agents to control and detect the prevalence of E . coli in animals and food.

Appl Environ Microbiol, 2003 Sep, 69(9), 5306 - 18
Population genetics of the nomenspecies Enterobacter cloacae; Hoffmann H et al.; The genetic heterogeneity of the nomenspecies Enterobacter cloacae is well known . Enterobacter asburiae, Enterobacter cancerogenus, Enterobacter dissolvens, Enterobacter hormaechei, Enterobacter kobei, and Enterobacter nimipressuralis are closely related to it and are subsumed in the so-called E . cloacae complex . DNA-DNA hybridization studies performed previously identified at least five DNA-relatedness groups of this complex . In order to analyze the genetic structure and the phylogenetic relationships between the clusters of the nomenspecies E . cloacae, 206 strains collected from 22 hospitals, a veterinarian, and an agricultural center in 11 countries plus all 13 type strains of the genus and reference strain CDC 1347-71(R) were examined with a combination of sequence and PCR-restriction fragment length polymorphism (PCR-RFLP) analyses of the three housekeeping genes hsp60, rpoB, and hemB as well as ampC, the gene of a class C beta-lactamase . Based on the neighbor-joining tree of the hsp60 sequences, 12 genetic clusters (I to XII) and an unstable sequence crowd (xiii) were identified . The robustness of the genetic clusters was confirmed by analyses of rpoB and hemB sequences and ampC PCR-RFLPs . Sequence crowd xiii split into two groups after rpoB analysis . Only three strains formed a cluster with the type strain of E . cloacae, indicating that the minority of isolates identified as E . cloacae truly belong to the species; 13% of strains grouped with other type strains of the genus, suggesting that the phenotypes of these species seem to be more heterogeneous than so far believed . Three clusters represented 70% of strains, but none of them included a type or reference strain . The genetic clustering presented in this study might serve as a framework for future studies dealing with taxonomic, evolutionary, epidemiological, or pathogenetic characteristics of bacteria belonging to the E . cloacae complex.

Lancet Infect Dis, 2003 Sep, 3(9), 537 - 46
Fluoroquinolones in paediatrics: a risk for the patient or for the community?
Gendrel D, Chalumeau M, Moulin F, Raymond J.
Fluoroquinolones are an important group of antibiotics widely used in adult patients because of their excellent tissue penetration and their bactericidal activity . They are not authorised for paediatric use (except the limited indication of pseudomonas infections in cystic fibrosis), however, because of the potential for joint toxicity reported from experiments with young animals . Despite the absence of official approval, fluoroquinolones are widely used in paediatrics as second-line antibiotics when all other treatments have failed . Most of the information available about paediatric use concerns ciprofloxacin, which is used in children much more often than the other members of this class . The published paediatric series have shown that frequency of articular side-effects varies according to age: all the surveys have reported frequencies of around 0.1% in adults and 2-3% in children . Outside of cystic fibrosis and severe infections in which no other treatment is possible, the only paediatric situations where fluoroquinolones are superior to standard treatments for children, in speed of recovery and comfort as well as in efficacy, are typhoid fever, severe shigella dysenteries, and enterobacteria meningitis . Should the use of new fluoroquinolones active against pneumococci be authorised for upper respiratory infections (including recurrent otitis) in children, the potential emergence and dissemination of pneumococci strains in which multidrug resistance includes fluoroquinolones would create a real risk in the community . It is, therefore, important to continue the policy of second-line use in children, only after failure of an earlier treatment, and when other antibiotics approved for paediatric use cannot be used.

Eur J Epidemiol, 2003, 18(7), 703 - 10
Comparative study of three different DNA fingerprint techniques for molecular typing of Shigella flexneri strains isolated in Romania; Surdeanu M et al.; In this study, 97 epidemiologically unrelated Shigella flexneri strains isolated during 1994 (69 isolates) and 1997 (28 isolates) were characterised by ribotyping, enterobacterial repetitive intergenic consensus sequence-based PCR typing, and pulsed-field gel electrophoresis . Number of strains belonging to each of the six serotypes is selected equal to their distribution in Romania . The isolates comprise 24 ribotypes based on combination of two restriction patterns obtained with HindlII and PstI, respectively, 7 enterobacterial repetitive intergenic consensus (ERIC)-PCR types, and 92 XbaI pulsed-field gel electrophoresis (PFGE) patterns grouped in 31 pulsotypes at Dice coefficients of 85% similarity . We find no significant difference in the distribution of isolates collected during the two periods . Macrorestriction analysis by PFGE offers maximal discrimination . There seems to be little genetic variability among circulating S . flexneri strains of serotype 2a, suggesting that even a combination of several molecular techniques, including PFGE, could not easily differentiate an outbreak strain from temporally associated independent isolates.

Exp Clin Endocrinol Diabetes, 2003 Aug, 111(5), 288 - 93
Lupus-like panniculitis in a patient with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED); Fuchtenbusch M et al.; Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disorder, characterised by a loss of self-tolerance to endocrine tissues, chronic candidiasis and ectodermal disorders . APECED is associated with mutations of a single gene, designated autoimmune regulator (AIRE) . We describe a 31-year-old APECED patient with non-traumatic, cutaneous ulcers on both forearms with features of a lupus-like panniculitis . On admission to the ICU in September 2001, the patient suffered from a ketoacidotic, hyperglycemic coma and adrenal crisis due to an Enterobacter-cloacae sepsis, originating from multiple, necrotising deep cutaneous ulcers . These ulcers spontaneously developed on both forearms, some of which were just emerging, full blown or healing with scars . Histological examination showed signs of a scarring panniculitis and vasculitis . Immunohistochemistry and direct immunofluorescence with characterisation of immunoglobulin and complement-factor binding pattern revealed features of a lupus-like panniculitis . Sequence analysis of all 14 exons of the AIRE gene revealed a R257 X mutation in exon 6 resulting in a nonsense mutation at codon 257 confirming the diagnosis of APECED . Oral treatment with 60 mg/day corticosteroids for two weeks led to complete resolution of all ulcers . In conclusion, mutations in the AIRE gene may provide the genetic background against which additional factors can initiate an autoimmune process . Here, autoimmune panniculitis appears to be an associated feature of the APECED syndrome . Our findings support the use of immunosuppressive therapy for autoimmune disease components of the APECED syndrome.

FEMS Microbiol Lett, 2003 Aug 29, 225(2), 257 - 62
Genetic evidence for the existence of two pathways for the biosynthesis of methionine in the Leptospira spp; Picardeau M et al.; There are two major pathways for methionine biosynthesis: the enterobacterial type transsulfuration pathway and the sulfhydrylation pathway as previously identified in the spirochete Leptospira meyeri . Sequence analysis of the L . meyeri metYX locus allows the identification of a third gene, called metW, which encodes a protein exhibiting similarities with homologs in many organisms belonging to the alpha-, beta-, and gamma-subdivisions of proteobacteria . The metW, metX and metY genes of L . meyeri were disrupted by a resistance cassette by homologous recombination . While the L . meyeri metX mutant shows methionine auxotrophy, the metY mutant (as well as the metW and metYmetW mutants) conserves methionine prototrophy, suggesting the presence of additional route(s) which may bypass the direct sulfhydrylation pathway . In addition, a L . interrogans gene, called metZ, was found to complement an Escherichia coli metB mutant, further suggesting that the transsulfuration pathway is also present in Leptospira spp.

FEMS Microbiol Lett, 2003 Aug 29, 225(2), 201 - 6
GASP phenotype: presence in enterobacteria and independence of sigmaS in its acquisition; Martinez-Garcia E et al.; The appearance of growth advantage in stationary phase or GASP was originally detected in Escherichia coli . The presence of this phenotype in other enterobacteria such as Enterobacter cloacae, Salmonella typhimurium, Providencia stuartii and Shigella dysenteriae is described in this work . E . cloacae GASP strains presented lower levels of RpoS than the parental strain, although no mutation in the gene or its promoter was detected . This work offers evidence of GASP rpoS-independent pathways as GASP was also acquired in knock-out rpoS E . cloacae and E . coli strains.

Biopolymers, 2003, 72(5), 391 - 8
Optical properties of Erwinia herbicola bacteria at 0.190-2.50 microm; Arakawa ET et al.; We measure the complex index of refraction of Erwina herbicola (also known as Enterobacter agglomerans or Pantoea agglomerans) bacteria (ATTC 33243) over the spectral region from 0.190 to 2.50 microm (4000-52,632 cm(-1)) . Transmission measurements are made on solid films of E . herbicola and on suspensions of the bacteria in water . These measurements, combined with spectral reflectance and Kramers-Kronig analysis, allow the determination of the real and imaginary parts over the entire wavelength interval . Accurate and consistent results are obtained for this complex and difficult to measure material . This is part of a continuing series of measurements of the optical constants of representative biological materials that are applicable to the development of methods for detection of airborne biological contaminants, where the material under study is used as a surrogate for a pathogenic agent .

Microbiology, 2003 Sep, 149(Pt 9), 2557 - 70
The colicin G, H and X determinants encode microcins M and H47, which might utilize the catecholate siderophore receptors FepA, Cir, Fiu and IroN; Patzer SI et al.; The colicin G producer Escherichia coli CA46, the colicin H producer E . coli CA58 and E . coli Nissle 1917 (DSM 6601) were shown to produce microcin H47 and the newly described microcin M . Both microcins were exported like colicin V by an RND-type export system, including TolC . The gene cluster encoding microcins H47 and M in strains CA46 and CA58 is nearly identical to that in strain DSM 6601, except that two additional genes are included . A Fur box identified in front of the microcin-encoding genes explained the observed iron regulation of microcin production . The catecholate siderophore receptors Fiu, Cir and FepA from E . coli and IroN, Cir and FepA from Salmonella were identified as receptors for microcins M, H47 and E492 . IroN takes up the glucose-containing catecholate siderophore salmochelin, whose synthesis is encoded in the iro gene cluster found in Salmonella and certain, often uropathogenic, E . coli strains . A gene in this iro cluster, iroB, which encodes a putative glycosyltransferase, was also found in the microcin H47/M and microcin E492 gene clusters . These microcins could aid the producing strain in competing against enterobacteria that utilize catecholate siderophores.

Mol Biol Evol, 2004 Jan, 21(1), 1 - 13 Epub 2003 Aug 29.
Site-specific recombination links the evolution of P2-like coliphages and pathogenic enterobacteria; Nilsson AS et al.; The genome of the tailed temperate coliphage P2 (Myoviridae) contains some genes that probably are horizontally transferred additions to the genome . One of these genes, the Z/fun gene, was recently found intact in the genome of Neisseria meningitidis . We have investigated the presence of P2-like phages, and the genetic variation at the position corresponding to the phage P2 Z/fun locus, in the Escherichia coli reference collection (ECOR) . P2-like phages are common in E . coli since they are present in about 30% of the ECOR strains . Hybridizations and PCR amplifications indicate that the overall variation among these phages is small . Amplification of the region corresponding to the phage P2 Z/fun locus in 11 prophages revealed that this is a multivariable locus . Sequencing of the region resulted in 10 completely different sequences but with a similar high AT-content as the Z/fun gene . All sequences contained at least one open reading frame with good transcription and translation signals . All sequences were also surrounded by a highly similar, previously undiscovered, inverted repeat (IR) . We also found this IR in genetically unstable regions in pathogenic enterobacteria . This demonstrates that P2-like phages are important factors in the evolution of bacteria, not only because they carry a diversity of lysogenic conversion genes but also because they can act as vectors for single genes . The genes found between the IRs have unknown functions, and only a few clearly similar genes have been found in other bacteria.

J Med Entomol, 2003 May, 40(3), 371 - 4
Bacteria in midguts of field-collected Anopheles albimanus block Plasmodium vivax sporogonic development; Gonzalez-Ceron L et al.; Bacterial infections were investigated in midguts of insectary and field-collected Anopheles albimanus Weidemann from southern Mexico . Serratia marcescens, Enterobacter cloacae and Enterobacter amnigenus 2, Enterobacter sp., and Serratia sp . were isolated in field samples obtained in 1998, but only Enterobacter sp . was recovered in field samples of 1997 and no bacteria were isolated from insectary specimens . These bacteria were offered along with Plasmodium vivax infected blood to aseptic insectary An . albimanus, and the number of infected mosquitoes as well as the oocyst densities assessed after 7d . Plasmodium vivax infections in mosquitoes co-infected with En . amnigenus 2, En . cloacae, and S . marcensces were 53, 17, and 210 times, respectively, lower than in control mosquitoes, and the mean oocyst density in mosquitoes co-infected with En . cloacae was 2.5 times lower than in controls . Mortality was 13 times higher in S . marcensces-infected mosquitoes compared with controls . The overall midgut bacterial infection in mosquito field populations may influence P . vivax transmission, and could contribute to explain the annual variations in malaria incidence observed in the area.

Jpn J Antibiot, 2003 Jun, 56(3), 171 - 9
{Susceptibility of major pathogens of acute pharyngitis and tonsillitis to levofloxacin and other oral antimicrobial drugs}; Matsuzaki K et al.; A total of 2865 strains of the causative organisms isolated from the patients with acute pharyngitis and tonsillitis at the primary medical institutions were used in this study . The MICs of levofloxacin (LVFX) and other oral antimicrobial drugs were determined and evaluated by the NCCLS guideline . LVFX, cefditoren (CDTR) and cefcapene (CFPN) were potently active against 773 isolates of Hemophilus influenzae, the MIC50S of LVFX being < or = 0.06 microgram/mL and also the same as the MIC90S of LVFX . LVFX was the most active against 496 isolates of Enterobacteriaceae . The MIC50S of LVFX were < or = 0.06 microgram/mL and were lower than those of CDTR, cefdinir (CFDN) and cefpodoxime (CPDX) (MIC50S: 0.5 microgram/mL) . The MIC90S of these cephems were markedly higher than the respective MIC50S, whereas MIC50 of LVFX was 0.12 microgram/mL, only twice the MIC50 . Against the majority of Streptococcus pyogenes (555 isolates) and Streptococcus spp . (495 isolates), CDTR, CFDN, CPDX and CFPN were highly active (MICs: < or = 0.06 microgram/mL), and clarithromycin (CAM) and azithromycin (AZM) were also active against these organisms (MICs: 0.12 to 0.25 microgram/mL) . Against S . pneumoniae (92 isolates), CDTR and CFDN were active (MIC50S: 0.12 and 0.25 microgram/mL, respectively) . However, the MIC90S of these drugs were 4-8 times the MIC50S . Against Moraxella (Branhamella) catarrhalis (454 isolates), LVFX was potently active, the MIC90 of LVFX being < or = 0.06 microgram/mL and MIC90S of the other cephems being 0.5 microgram/mL or more . When the susceptibility of these strains to LVFX was evaluated by the NCCLS guideline, about 3% of other Streptococcus spp . were resistant to the drug but no test strains resistant to LVFX were detected in H . influenzae, S . pyogenes or Enterobacteriaceae . On the other hand, the percentages of strains susceptible to the cephems tested were 60-90%, which were quite different according to kinds of drugs and species used . Furthermore, the strains of S . pneumoniae resistant to CFDN and CPDX, and those to CAM and AZM were 21-25% and 50% or more, respectively, whereas no LVFX-resistant strains were detected . The major pathogens isolated from patients with pharyngitis and tonsillitis in the primary institutions were highly susceptible to LVFX . These results suggest that LVFX is a useful drug which is potently active against the strains resistant to oral cephem and macrolide antibiotics.

J Eur Acad Dermatol Venereol, 2003 Sep, 17(5), 575 - 7
Cutaneous infection caused by Salmonella typhi; Marzano AV et al.; Salmonella typhi is a flagellated, gram-negative bacillus belonging to the family Enterobacteriaceae responsible for typhoid fever, which is a prolonged bacteraemic, systemic illness with minimal, at least initially, diarrhoea . Localized infection is a not uncommon complication of salmonella septicaemia, particularly occurring in immunocompromised patients . However, salmonella localization to the skin presenting as cutaneous ulceration is regarded as a rare event . We report a unique case of such a presentation as the sole clinical manifestation of infection with S . typhi and highlight the possible salmonella aetiology for unusual cutaneous lesions in individuals coming from endemic areas.

Infect Control Hosp Epidemiol, 2003 Aug, 24(8), 607 - 12
Resistance in Enterobacteriaceae: results of a multicenter surveillance study, 1995-2000; Friedland I et al.; OBJECTIVES: To assess changes over time in susceptibility of Enterobacteriaceae from patients in ICUs, compare susceptibility rates of isolates from patients in ICUs with those from inpatients outside ICUs, and explore phenotypic patterns of cross-resistance and co-resistance . DESIGN: From 1995 to 2000, centers participating in the ICU Surveillance Study tested 100 to 200 consecutive nosocomial gram-negative bacilli by broth microdilution . SETTING: Each year, 42 to 97 U.S . hospitals tested isolates . RESULTS: In all years, imipenem was the most potent agent tested, followed by amikacin and ertapenem . Extended-spectrum beta-lactam and monobactam agents had good activity against Escherichia coli and Klebsiella species, but limited activity against Enterobacter species . Susceptibility to imipenem and amikacin did not fluctuate during the analysis period, whereas susceptibility to ceftazidime, ceftriaxone, and ciprofloxacin decreased 2% to 5% . The decline was most pronounced for susceptibility of Escherichia coli to ciprofloxacin: 98.7% of ICU isolates were susceptible in 1995 versus 93.2% in 2000 . Susceptibility of ICU isolates was lower than that of non-ICU isolates, except for ciprofloxacin, for which the reverse was true . Cross-resistance was common among extended-spectrum cephalosporins and penicillins, but uncommon between imipenem and ertapenem . Only imipenem and ertapenem remained highly active against Enterobacteriaceae with a phenotype suggesting possible production of an extended-spectrum beta-lactamase and those with a phenotype suggesting possible Amp C hyperproduction . CONCLUSIONS: Imipenem was the most active agent against nosocomial Enterobacteriaceae . Susceptibility to ciprofloxacin decreased from 1995 to 2000, particularly in Escherichia coli, and, in contrast to other agents, was lower among non-ICU isolates.

Antimicrob Agents Chemother, 2003 Sep, 47(9), 2864 - 7
Extended-spectrum beta-lactamases in enterobacteriaceae in Buenos Aires, Argentina, public hospitals; Quinteros M et al.; Resistance to extended-spectrum cephalosporins is often associated with plasmid encoded extended spectrum beta-lactamases (ESBL) . In order to evaluate the prevalence and diversity of ESBLs in enterobacteria in our city, a 1-month-period survey was carried out from April to May 2000 . Extended-spectrum-cephalosporin-resistant strains, isolated from inpatient clinical specimens other than stools, were collected among 17 participating hospitals . From a total of 427 enterobacterial strains that were collected during this period, 39 were extended-spectrum cephalosporin resistant . The National Committee for Clinical Laboratory Standards' Screening and Confirmatory Tests for ESBL production were performed using cefotaxime and ceftazidime; cefepime and cefepime-clavulanic acid-containing disks were included . beta-Lactamases were characterized by isoelectric focusing and PCR amplification using specific primers . Three different ESBLs were detected: SHV-related (4 isolates), PER-2-type (9 isolates), and CTX-M-2-related (26 isolates) . Sequencing of the corresponding genes confirmed CTX-M-2 in 19 of 21 and CTX-M-31 (an allelic variant) in the remaining 2 of 21 . CTX-M-2 (or its variant) was detected in all Escherichia coli, Enterobacter aerogenes, Serratia marcescens, Proteus mirabilis, and Providencia stuartii strains, while PER-2 was detected in Enterobacter cloacae, E . aerogenes, and Klebsiella pneumoniae; SHV-related ESBL were found only in K . pneumoniae . These results clearly show that CTX-M-2 is the most prevalent ESBL produced by enterobacterial species isolated from public hospitals in Buenos Aires.

Chin Med J (Engl), 2003 Aug, 116(8), 1244 - 7
The status of drug resistance and ampC gene expression in Enterobacter cloacae; Zhou Z et al.; OBJECTIVE: To investigate the status of the drug resistance and the ampC gene expression of Enterobacter cloacae . METHODS: Disk diffusion tests were made for detecting the susceptibility of antimicrobial agents against Enterobacter cloacae . AmpC gene was amplified by polymerase chain reaction (PCR) and verified by DNA sequencing . AmpC gene expression was analyzed according to antimicrobial agent sensitive phenotype . RESULTS: The sensitivity rates of 144 strains to imipenam, cefepime and cefoperazone/sulbactam were 98.61%, 65.97% and 63.89%, respectively . The sensitivity rates of 144 strains to other antimicrobial agents were lower . Among the 144 strains 120 were found to be positive by PCR for ampC . The PCR product showed high homology to the GenBank ampC sequence . Stably derepressed strains, hyperinducible strains and unexpressing or lower level expressing strains accounted for 30.0% (36/120), 37.5% (45/120), and 32.5% (39/120), respectively . Fifty-six out of 120 strains (46.67%) also produced extended spectrum beta-lactamases (ESBLs) . The hyperinducible strains were highly sensitive to all the antimicrobial agents except amoxicillin/clavulanic acid and cefuroxime, while the stably derepressed strains were only sensitive to imipenam and cefepime . However, sensitivity to cefepime decreased if the strains also produced ESBLs . CONCLUSIONS: The drug resistant status of Enterobacter cloacae is severe . Clearing out the expressive status of ampC gene will be helpful in selection of antimicrobial agents in the treatment of clinical infection.

J Endotoxin Res, 2003, 9(4), 244 - 9
Molecular insights into the assembly and diversity of the outer core oligosaccharide in lipopolysaccharides from Escherichia coli and Salmonella; Whitfield C et al.; In the Enterobacteriaceae, the core oligosaccharide provides the junction between the highly conserved lipid A and the remarkably diverse polysaccharide O antigen . The basic structure of the inner (lipid A-proximal) core is well conserved, perhaps reflecting constraints imposed by its involvement in the structural integrity of the outer membrane . However, non-stoichiometric modifications do create some structural variants . The outer core may show more variation . Efforts to develop immunoprophylactic strategies based on the core oligosaccharide require a detailed understanding of core immunochemistry, the accessibility of specific epitopes in the LPS, and the distribution of specific structures within natural populations . The availability of sequences for the waa (core biosynthesis) loci and functional data for the gene products provide a molecular basis for the known structural diversity in Escherichia coli and Salmonella core oligosaccharide . Surveys of waa-locus organization have established the distribution of these core types in natural populations and have identified genetic variants that provide candidates for additional novel structures.

Tidsskr Nor Laegeforen, 2003 Aug 14, 123(15), 2021 - 2
{Urinary tract pathogens in uncomplicated lower urinary tract infections in women in Norway}; Jureen R et al.; BACKGROUND: We wanted to investigate the antimicrobial susceptibility of urinary tract pathogens in uncomplicated lower urinary tract infections in adult women in Norway . MATERIAL AND METHODS: Urine samples from 312 adult women with symptoms of uncomplicated urinary tract infections from eight general practices were included . RESULTS: Significant bacteriuria was found in 187 samples (60%) . E coli was isolated from 153 (82%) of these samples . Other isolated uropathogens were S saprophyticus 18 (10%), Proteus spp 6 (3%), Klebsiella spp 4 (2%), Enterobacter spp 2 (1%), enterococci 1 (0.5%) and other Gram-positive bacteria 3 (1,5%) . No fungi were isolated . Of the E coli isolates, 1 %, 1 % and 9 % were resistant to nitrofurantoin, mecillinam and trimetoprim respectively . All S saprophyticus isolates were sensitive to nitrofurantoin and trimetoprim . INTERPRETATION: Antibiotic resistance of urinary tract pathogens causing uncomplicated urinary tract infections in adult women in general practice is still low in Norway.

Infect Immun, 2003 Sep, 71(9), 5087 - 96
A novel pathogenicity island integrated adjacent to the thrW tRNA gene of avian pathogenic Escherichia coli encodes a vacuolating autotransporter toxin; Parreira VR et al.; We report the complete nucleotide sequence and genetic organization of the Vat-encoding pathogenicity island (PAI) of avian pathogenic Escherichia coli strain Ec222 . The 22,139-bp PAI is situated adjacent to the 3' terminus of the thrW tRNA gene, has a G+C content of 41.2%, and includes a bacteriophage SfII integrase gene, mobile genetic elements, two open reading frames with products exhibiting sequence similarity to known proteins, and several other open reading frames of unknown function . The PAI encodes an autotransporter protein, Vat (vacuolating autotransporter toxin), which induces the formation of intracellular vacuoles resulting in cytotoxic effects similar to those caused by the VacA toxin from Helicobacter pylori . The predicted 148.3-kDa protein product possesses the three domains that are typical of serine protease autotransporters of Enterobacteriaceae: an N-terminal signal sequence of 55 amino acids, a 111.8-kDa passenger domain containing a modified serine protease site (ATSGSG), and a C-terminal outer membrane translocator of 30.5 kDa . Vat has 75% protein homology with the hemagglutinin Tsh, an autotransporter of avian pathogenic E . coli . A vat deletion mutant of Ec222 showed no virulence in respiratory and cellulitis infection models of disease in broiler chickens . We conclude that the newly described PAI and Vat may be involved in the pathogenicity of avian septicemic E . coli strain Ec222 and other avian pathogenic E . coli strains.

Oral Microbiol Immunol, 2003 Oct, 18(5), 329 - 32
Sensitivity of genera Porphyromonas and Prevotella to the bactericidal action of C-terminal domain of human CAP18 and its analogues; Isogai E et al.; This paper reports the effect of the synthesized 27-amino acid sequence in the C-terminal domain of human CAP18 (hCAP18), a human cationic antibacterial protein or cathelicidin, on certain strains belonging to the genera Porophyromonas and Prevotella . The domain binds lipopolysaccharides (LPS) from Porophyromonas gingivalis and Porophyromonas circumdentaria as well as enterobacterial LPS . Two analogues of hCAP18, designated LL/CAP18 and FF/CAP18, were also tested to determine whether additional activity was obtained . The analogue peptides replaced with hydrophobic and cationic amino acid residues showed more potent bactericidal and LPS-binding activities than the original one.

J Food Prot, 2003 Aug, 66(8), 1486 - 9
Survey of shell egg processing plant sanitation programs: effects on egg contact surfaces; Jones DR et al.; Sanitation standard operating procedures (SSOPs) are an integral component of process control and are often the first step in the implementation of food safety regulations . The objective of this study was to assess and compare the efficacies of sanitation programs used in a variety of shell egg processing facilities . In-line, off-line, and mixed operations were evaluated . Sixteen direct or indirect egg contact surfaces were sampled in various shell egg processing facilities in the southeast United States . Samples were collected at the end of a processing day (POST) and again the next morning before operations began (PRE) . Total aerobic plate counts (APCs) were obtained and Enterobacteriacae were enumerated . No significant differences (P > 0.05) between POST and PRE bacterial counts were found for the 16 sampling sites . In general, high APCs were found on the wall of the recirculating water tank both POST and PRE . The APCs for the rewash belt were considerably high for all plants sampled . APCs were also high for the vacuum loaders . APCs for washers and washer brushes were relatively low for most plants sampled . PRE and POST levels of plant sanitation, as determined by direct microbial plating, did not differ significantly . At this point, it is difficult to draw definitive conclusions about how rigid SSOPs should be for the shell egg processing industry.

Int J Antimicrob Agents, 2003 Aug, 22(2), 147 - 54
In vitro susceptibility of 4903 bacterial isolates to gemifloxacin--an advanced fluoroquinolone; Blondeau JM et al.; The in vitro activity of gemifloxacin against over 4900 bacterial isolates was determined by microbroth dilution with interpretation in accordance with NCCLS guidelines . Susceptibility results were compared with those for ciprofloxacin, gatifloxacin, levofloxacin and moxifloxacin . Gemifloxacin and the other fluoroquinolones were not affected by either beta-lactamase production or penicillin-resistance in Streptococcus pneumoniae . The MIC90 values for gemifloxacin were: S . pneumoniae 0.063 mg/l; Haemophilus influenzae 0.016 mg/l; Moraxella catarrhalis 0.008 mg/l, methicillin-susceptible Staphylococcus aureus 0.063 mg/l; methicillin-susceptible Streptococcus pyogenes 0.031 mg/l; Enterobacteriaceae 0.031-0.16 mg/l; Pseudomonas aeruginosa 4 mg/l; Neisseria meningitidis 0.008 mg/l . The MIC90 for gemifloxacin was lower than those for the other quinolones tested against S . pneumoniae (ciprofloxacin 2-4 mg/l, gatifloxacin 0.5 mg/l, levofloxacin 1-2 mg/l, moxifloxacin 0.25 mg/l) . This study confirms the enhanced potent activity of gemifloxacin against Gram-positive pathogens, its broad-spectrum, Gram-negative activity and indicates that gemifloxacin is likely to have an important role in treating patients with Gram-positive and/or Gram-negative infections.

Int J Antimicrob Agents, 2003 Aug, 22(2), 128 - 33
Molecular epidemiology of Enterobacteriaceae producing extended-spectrum beta-lactamase in a French university-affiliated hospital; Bertrand X et al.; We conducted a retrospective study to investigate the epidemiology of Enterobacteriaceae producing extended-spectrum beta-lactamase (ESBLE) in our hospital . We determined the occurrence of extended-spectrum beta-lactamase (ESBL) in Enterobacteriaceae over a 2-year period . We also characterised ESBLs by isoelectric focusing (IEF) and investigated the epidemiological relatedness of EBLSE by pulsed field gel electrophoresis (PFGE) . During this period, 70 patients were colonised/infected with one or several strains of EBLSE, giving a crude incidence of 0.095 per 1000 patient-days . We found that ESBL-producing Enterobacter aerogenes were the main source of ESBLE dissemination . Indeed, 59.5% of ESBLE were E . aerogenes and 21.9% of the other ESBLE resulted from a plasmid transfer originating from E . aerogenes . IEF and PFGE analysis demonstrated that the dissemination of ESBL from E . aerogenes in our hospital was due to a single clone that always harbours TEM-24 . This emphasises the importance of standard contact isolation precautions and the early detection of ESBLE-colonised patients in high risk departments like intensive care units.

J Anim Sci, 2003 Aug, 81(8), 2019 - 31
Fermented and nonfermented liquid feed to growing pigs: effect on aspects of gastrointestinal ecology and growth performance; Canibe N et al.; The effect of feeding dry feed (DF), nonfermented liquid feed (NFLF), and fermented liquid feed (FLF) to growing pigs on aspects of gastrointestinal ecology and on performance was investigated . Nonfermented liquid feed was prepared by mixing feed and water at a ratio of 1:2.5 immediately before feeding . Fermented liquid feed was prepared by mixing feed and water in the same ratio as NFLF, and stored in a tank at 20 degrees C for 4 d, after which half the volume was removed twice daily at each feeding and replaced with the same volume of feed and water mixture . A total of 60 pigs (initial BW of 30.7 kg) from 20 litters was used . Twenty pigs, housed individually, were allotted to each of the diets and fed restrictively . Five pigs from each diet were sacrificed at an average BW of 112 kg and digesta from the gastrointestinal tract (GI-tract) was obtained to examine variables describing some aspects of the gastrointestinal ecology . Fermented liquid feed contained high levels of lactic acid bacteria (9.4 log cfu/g) and lactic acid (approximately 169 mmol/kg), low levels of enterobacteria (<3.2 log cfu/g), and had a low pH (4.4) . Nonfermented liquid feed contained 7.2 log cfu/g of lactic acid bacteria, and 6.2 log cfu/g of enterobacteria, which indicated that fermentation had started in the feed . The pigs fed FLF had the lowest levels of enterobacteria along the GI-tract (<3.2 to 5.0 log cfu/g), and those fed NFLF the highest levels (5.7 to 6.6 log cfu/g; P < or = 0.02) . Fermented liquid feed caused a decrease in gastric pH from 4.4 and 4.6 for DF and NLF, to 4.0 (P = 0.003), and increased numerically the gastric concentration of lactic acid (P = 0.17) from 50 to 60 mmol/kg in the DF and NFLF treatments to 113 mmol/kg in the FLF treatment . The animals fed NFLF showed the highest weight gain (995 g/d) and feed intake (2.14 kg/d), and those fed FLF the lowest values (weight gain, 931 g/d; feed intake, 1.96 kg/d; P = 0.003 for weight gain, and P < 0.001 for feed intake) . The results from the present study indicate that feeding FLF as prepared here may be a valid feeding strategy to decrease the levels of enterobacteria in the GI-tract of growing pigs, whereas feeding liquid feed that has started to ferment (high levels of enterobacteria and high pH as with NFLF) increases the presence of these undesirable bacteria . Nonetheless, higher daily feed intake and body weight gain are obtained when feeding NFLF compared with feeding FLF or DF.

J Bone Joint Surg Am, 2003 Aug, 85-A(8), 1454 - 60
Necrotizing fasciitis: clinical presentation, microbiology, and determinants of mortality; Wong CH et al.; BACKGROUND: Necrotizing fasciitis is a life-threatening soft-tissue infection primarily involving the superficial fascia . The present report describes the clinical presentation and microbiological characteristics of this condition as well as the determinants of mortality associated with this uncommon surgical emergency . METHODS: The medical records of eighty-nine consecutive patients who had been admitted to our institution for necrotizing fasciitis from January 1997 to August 2002 were reviewed retrospectively . RESULTS: The paucity of cutaneous findings early in the course of the disease makes the diagnosis difficult, and only thirteen of the eighty-nine patients had a diagnosis of necrotizing fasciitis at the time of admission . Preadmission treatment with antibiotics modified the initial clinical picture and often masked the severity of the underlying infection . Polymicrobial synergistic infection was the most common cause (forty-eight patients; 53.9%), with streptococci and enterobacteriaceae being the most common isolates . Group-A streptococcus was the most common cause of monomicrobial necrotizing fasciitis . The most common associated comorbidity was diabetes mellitus (sixty-three patients; 70.8%) . Advanced age, two or more associated comorbidities, and a delay in surgery of more than twenty-four hours adversely affected the outcome . Multivariate analysis showed that only a delay in surgery of more than twenty-four hours was correlated with increased mortality (p < 0.05; relative risk = 9.4) . CONCLUSIONS: Early operative debridement was demonstrated to reduce mortality among patients with this condition . A high index of suspicion is important in view of the paucity of specific cutaneous findings early in the course of the disease.

J Bacteriol, 2003 Sep, 185(17), 5328 - 32
Role for Salmonella enterica enterobacterial common antigen in bile resistance and virulence; Ramos-Morales F et al.; Passage through the digestive tract exposes Salmonella enterica to high concentrations of bile salts, powerful detergents that disrupt biological membranes . Mutations in the wecD or wecA gene, both of which are involved in the synthesis of enterobacterial common antigen (ECA), render S . enterica serovar Typhimurium sensitive to the bile salt deoxycholate . Competitive infectivity analysis of wecD and wecA mutants in the mouse model indicates that ECA is an important virulence factor for oral infection . In contrast, lack of ECA causes only a slight decrease in Salmonella virulence during intraperitoneal infection . A tentative interpretation is that ECA may contribute to Salmonella virulence by protecting the pathogen from bile salts.

J Bacteriol, 2003 Sep, 185(17), 5314 - 9
IS1999 increases expression of the extended-spectrum beta-lactamase VEB-1 in Pseudomonas aeruginosa; Aubert D et al.; The integron-borne bla(VEB-1) gene encodes an extended-spectrum beta-lactamase . This gene was associated mostly with IS1999 and rarely with an additional IS2000 element in Pseudomonas aeruginosa isolates from Thailand, whereas IS1999 was only very rarely associated with bla(VEB-1) in Enterobacteriaceae . Expression experiments and promoter study identified promoter sequences in IS1999 that increased the expression of VEB-1 in P . aeruginosa.

Arch Biochem Biophys, 2003 Sep 1, 417(1), 12 - 7
Antioxidative flavonoid quercetin: implication of its intestinal absorption and metabolism; Murota K et al.; Quercetin is a typical flavonoid ubiquitously present in fruits and vegetables, and its antioxidant effect is implied to be helpful for human health . The bioavailability of quercetin glycosides should be clarified, because dietary quercetin is mostly present as its glycoside form . Although quercetin glycosides are subject to deglycosidation by enterobacteria for the absorption at large intestine, small intestine acts as an effective absorption site for glucose-bound glycosides (quercertin glucosides) . This is because small intestinal cells possess a glucoside-hydrolyzing activity and their glucose transport system is capable of participating in the glucoside absorption . A study using a cultured cell model for intestinal absorption explains that the hydrolysis of the glucosides accelerates their absorption in the small intestine . Small intestine is also recognized as the site for metabolic conversion of quercetin and other flavonoids as it possesses enzymatic activity of glucuronidation and sulfation . Modulation of the intestinal absorption and metabolism may be beneficial for regulating the biological effects of dietary quercetin.

Drugs, 2003, 63(17), 1855 - 78
Ertapenem: a review of its use in the management of bacterial infections; Curran M et al.; Ertapenem, a carbapenem antibacterial, has in vitro activity against many Gram- negative (including Enterobacteriaceae) and Gram-positive aerobic and anaerobic bacteria that are commonly associated with various infections.Once-daily parenteral (intravenous or intramuscular) ertapenem 1g was as effective as comparator antimicrobial agents (piperacillin/tazobactam or ceftriaxone +/- metronidazole) in patients with bacterial infections in randomised, double-blind, multicentre clinical trials . Response rates with ertapenem were 84% and 87% (combined microbiological and clinical) in patients with complicated intra-abdominal infections (CIAI), 82% (clinical) in patients with complicated skin and skin structure infections (CSSSI), 86% and 92% (microbiological) in patients with complicated urinary tract infections (CUTI), 92% (clinical) in patients with community-acquired pneumonia (CAP) associated with typical pathogens and 94% (clinical) in patients with acute pelvic infection . Respective response rates were statistically equivalent to those with comparators (81-94%) . The efficacy of ertapenem was equivalent to that of piperacillin/tazobactam in patients infected with Enterobacteriaceae or anaerobes and to ceftriaxone in patients infected with Enterobacteriaceae . Ertapenem was generally well tolerated by patients with bacterial infections, with most adverse events being mild to moderate in severity . The most common ertapenem-associated adverse events were diarrhoea, infused vein complication, nausea, headache, vaginitis in females, phlebitis and/or thrombophlebitis and vomiting . CONCLUSION: Ertapenem is a broad-spectrum parenteral antibiotic with activity against many Gram-negative (including Enterobacteriaceae) and Gram-positive aerobic and anaerobic bacteria and is suitable for once-daily administration . Ertapenem has a role in the treatment of CAP associated with typical respiratory pathogens and is of particular value in the treatment of polymicrobial infections (such as CIAI, CSSSI, CUTI and acute pelvic infections), especially where Enterobacteriaceae and anaerobic bacteria are involved.

J Antimicrob Chemother, 2003 Sep, 52(3), 389 - 96 Epub 2003 Aug 13.
Comparison of microbial adherence to antiseptic and antibiotic central venous catheters using a novel agar subcutaneous infection model; Gaonkar TA et al.; An agar subcutaneous infection model (agar model), which simulates the rat subcutaneous infection model (rat model), was developed to assess the ability of antimicrobial catheters to resist microbial colonization . The catheters were implanted in the agar and rat models and the insertion sites were infected immediately or on day 7, 14 or 21 post-implantation . The catheters implanted in the agar model were transferred to fresh media one day before infection on day 7, 14 or 21 . The efficacy of chlorhexidine and silver sulfadiazine impregnated (CS) catheters, CS catheters with higher levels of chlorhexidine (CS+ catheters), minocycline-rifampicin (MR) catheters and silver catheters against Staphylococcus aureus and rifampicin-resistant Staphylococcus epidermidis RIF-r2 was compared in the agar and rat models . No significant difference in the adherence or the drug release was found between the in vitro and in vivo models . In both models, CS+ and MR catheters were effective against S . aureus even when infected on day 14, whereas CS catheters were colonized when challenged on day 7 . CS+ catheters were effective against S . epidermidis RIF-r2, whereas MR catheters showed adherence when infected on day 7 . CS+ catheters prevented colonization of all the organisms including, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Candida albicans in the agar model, whereas MR catheters were effective only against S . aureus and S . epidermidis strains . Silver catheters were ineffective against all the organisms . The agar model may be used to predict the in vivo efficacy of antimicrobial catheters against various pathogens.

J Antimicrob Chemother, 2003 Sep, 52(3), 331 - 44 Epub 2003 Aug 13.
Properties and potential of ertapenem; Livermore DM et al.; Ertapenem is a carbapenem that shares the activity of imipenem and meropenem against most species, but is less active against non-fermenters . Activity is retained against most strains with AmpC and extended-spectrum beta-lactamases, although resistance can arise if these enzymes are combined with extreme impermeability . Resistance can also be caused by IMP, VIM, KPC and NMC carbapenemases, but again, co-requires impermeability . Although the spread of carbapenemases in the future is a concern, they are currently very rare . Given as a 1 g intravenous (iv) infusion once daily, ertapenem has a plasma half-life of approximately 4 h in healthy volunteers, and a Cmax of 155 mg/L and 13 mg/L for total and free drug, respectively . Excretion is largely renal, divided equally between native drug and an open-ring derivative . Trials show equivalence to piperacillin/tazobactam or ceftriaxone in (a) intra-abdominal infections, (b) community-acquired pneumonia, (c) acute pelvic infections, (d) skin and skin structure infections and (e) complicated urinary tract infections . The USA licence grants all these five indications; the EU licence grants the first three . Further potential uses include home iv therapy, directed therapy against Enterobacteriaceae with AmpC or extended-spectrum cephalosporinases, and tentatively, surgical prophylaxis . Widening the usage of carbapenems raises public health concerns, somewhat allayed by the continued rarity of carbapenemases after 17 years of imipenem use, and by the fact that carbapenemases occur mostly in non-fermenters outside the spectrum of ertapenem, and co-require impermeability to confer resistance in Enterobacteriaceae . Nevertheless, if ertapenem is to be used widely, its effects on the resistance ecology need to be monitored carefully.

Acta Microbiol Pol, 2003, 52(1), 81 - 6
Siderophore-mediated strategies of iron acquisition by extraintestinal isolates of Enterobacter spp; Mokracka J et al.; A total of 89 examined Enterobacter isolates belonging to three species: E . cloaceae, E . aerogenes and E . sakazakii, produced iron chelators detected in universal CAS assay . In chemical assays the strains were shown to excrete mostly catecholate (88 strains) and hydroxamate (42 strains) type of siderophores . Forty-one strains produced both catecholate and hydroxamate siderophores whereas one isolate produced only hydroxamate . Besides, the isolates were screened for genes coding for another siderophore: yersiniabactin . The genes for biosynthesis and uptake of yersiniabactin are located on the high-pathogenicity island (HPI) of Yersinia spp . The presence of three marker genes irp1, irp2 and fyuA was estimated by polymerase chain reaction . Two strains: E . aerogenes and E . cloaceae possessed irp1, irp2 and fyuA genes . PCR products of irp1, irp2 and fyuA were of 240, 280 and 780 bp, respectively.

Antibiot Khimioter, 2003, 48(3), 26 - 9
{Sulperazone in the treatment of severe infections in patients with cancer}; Mitrokhin SD; For the evaluation of rational sulperazone position in oncological hospital and elaboration of its implementation criteria investigation was performed . The trial included 193 patients (88 patients with injuries, 66 with hospital pneumonia, 39 with urinary track infection) . From different clinical material of the patients were isolated 136 straines of Gram-negative bacteria . Suseptibile to sulperazone were 67 per cent of P . aeruginosa, 78-86 per cent of P . vulgaris, Klebsiella and E . coli isolates, 66 {symbol: see text} 60 per cent of Enterobacter and Serratia isolates subsequently . Comparative results of treatment with sulperazone as monotherapy and for combination with aminoglycosides (gentamycin or amicacin) in the case of P . aeruginosa infection demonstrated high sulperazone efficacy not lower than imipenem/cilsatatin and cefepime efficacy in the case of hospital infections treatment at critical care units . Low price of the sulperazone treatment when compared to imipenem/cilastatine is emphasized . Another advantage of sulperazone when compared to cefepime is anaerobic infection treatment--cefepime is administered in combination with metronidazole while sulperazone is used in monotherapy.

J Appl Microbiol, 2003, 95(3), 428 - 36
Transfer of antibiotic resistance between commensal and pathogenic members of the Enterobacteriaceae under ileal conditions; Blake DP et al.; AIM: To determine the rate of antibiotic resistance transmission between commensal and pathogenic representatives of the Enterobacteriaceae . METHODS AND RESULTS: Through the use of a validated in vitro simulation of the porcine ileum, the transmission of antibiotic resistance was detected between commensal Escherichia coli, E . coli O157 and Salmonella spp . Countable transconjugant populations arose readily and, in one example, proved capable of indefinite persistence . CONCLUSIONS: Genetic material conferring antibiotic resistance is readily transmissible between members of the Enterobacteriaceae under ileal conditions . Recipient phenotype influences the persistence of multi-resistant transconjugants . SIGNIFICANCE AND IMPACT OF THE STUDY: The observation that the conjugal transmission of antibiotic resistance is commonplace under ileal conditions impacts primarily on the risk of food contamination by multi-resistant bacteria . The establishment of a multi-resistant transconjugant population as a dominant member of the microflora maintains a genetic reservoir of antimicrobial resistance.

Appl Microbiol Biotechnol, 2004 Feb, 63(6), 666 - 71 Epub 2003 Aug 09.
Synthesis of FimH receptor-active manno-oligosaccharides by reverse hydrolysis using alpha-mannosidases from Penicillium citrinum, Aspergillus phoenicis and almond; Maitin V et al.; Recombinant Penicillium citrinum alpha-1,2-mannosidase, expressed in Aspergillus oryzae, was employed to carry out regioselective synthesis of alpha- d-mannopyranosyl-(1-->2)- d-mannose . Yields (w/w) of 16.68% disaccharide, 3.07% trisaccharide and 0.48% tetrasaccharide were obtained, with alpha1-->2 linkages present at 98.5% of the total linkages formed . Non-specific alpha-mannosidase from almond was highly efficient in reverse hydrolysis and oligosaccharide yields of 45-50% were achieved . The products of the almond mannosidase were a mixture of disaccharides (30.75%, w/w), trisaccharides (12.26%, w/w) and tetrasaccharides (1.89%, w/w) with 1-->2, 1-->3 and 1-->6 isomers . alpha-1,2-linkage specific mannosidase from P . citrinum and alpha-1,6-linkage-specific mannosidase from Aspergillus phoenicis were used in combination to hydrolyse the respective linkages from the mixture of isomers, resulting in alpha- d-mannopyranosyl-(1-->3)- d-mannose in 86.4% purity . The synthesised oligosaccharides can potentially inhibit the adhesion of pathogens by acting as "decoys" of receptors of type-1 fimbriae carried by enterobacteria.

J Clin Microbiol, 2003 Aug, 41(8), 3790 - 800
Rapid identification of bacteria from positive blood cultures by terminal restriction fragment length polymorphism profile analysis of the 16S rRNA gene; Christensen JE et al.; Bacteremia results in significant morbidity and mortality, especially among patient populations that are immunocompromised . Broad-spectrum antibiotics are administered to patients suspected to have bloodstream infections that are awaiting diagnosis that depends on blood culture analysis . Significant delays in identification of pathogens can result, primarily due to the dependence on growth-based identification systems . To address these limitations, we took advantage of terminal restriction fragment (TRF) length polymorphisms (T-RFLP) due to 16S ribosomal DNA (rDNA) sequence diversity to rapidly identify bacterial pathogens directly from positive blood culture . TRF profiles for each organism were determined by sizing fragments from restriction digests of PCR products derived from two sets of 16S rDNA-specific fluorescent dye-labeled primers . In addition, we created a TRF profile database (TRFPD) with 5899 predicted TRF profiles from sequence information representing 2860 different bacterial species . TRF profiles were experimentally determined for 69 reference organisms and 32 clinical isolates and then compared against the predicted profiles in the TRFPD . The predictive value of the profiles was found to be accurate to the species level with most organisms tested . In addition, identification of 10 different genera was possible with profiles comprising two or three TRFs . Although it was possible to identify Enterobacteriaceae by using a profile of three TRFs, the similarity of the TRF profiles of these organisms makes differentiation of species less reliable with the current method . The ability to rapidly (i.e., within approximately 8 h) identify bacteria from blood cultures has potential for reducing unnecessary use of broad-spectrum antibiotics and promoting more timely prescription of appropriate antibiotics.

Nucleic Acids Symp Ser, 2000, (44), 25 - 6
Study on highly diastereoselective synthesis of (2'R)-2'-deoxy{2'-2H}guanosine; Kawashima E et al.; To develop an efficient method for the synthesis of a highly diasteroselective (2'R)-2'-deoxy{2'-2H}guanosine (1), studies of organic chemical conversion from 2'-bromo-2'-deoxy-N2-Isobutyryl-3',5'-O-TIPDS-guanosine (2) to 1 and a biological transdeoxyribofuranosylation of (2'R > 98% de)-2'-deoxy{2'-2H}uridine (4) were carried out . As the results, a highly diastereoselective synthesis of 1 was achieved by a biological transdeoxyribofuranosylation between 2,6-diaminopurine and 4 by the use of Enterobacter aerogenes AJ-11125, followed by treatment with adenosine deaminase . The results will be described in detail.

Appl Environ Microbiol, 2003 Aug, 69(8), 4915 - 26
Colonization of Arabidopsis thaliana with Salmonella enterica and enterohemorrhagic Escherichia coli O157:H7 and competition by Enterobacter asburiae; Cooley MB et al.; Enteric pathogens, such as Salmonella enterica and Escherichia coli O157:H7, have been shown to contaminate fresh produce . Under appropriate conditions, these bacteria will grow on and invade the plant tissue . We have developed Arabidopsis thaliana (thale cress) as a model system with the intention of studying plant responses to human pathogens . Under sterile conditions and at 100% humidity, S . enterica serovar Newport and E . coli O157:H7 grew to 10(9) CFU g(-1) on A . thaliana roots and to 2 x 10(7) CFU g(-1) on shoots . Furthermore, root inoculation led to contamination of the entire plant, indicating that the pathogens are capable of moving on or within the plant in the absence of competition . Inoculation with green fluorescent protein-labeled S . enterica and E . coli O157:H7 showed invasion of the roots at lateral root junctions . Movement was eliminated and invasion decreased when nonmotile mutants of S . enterica were used . Survival of S . enterica serovar Newport and E . coli O157:H7 on soil-grown plants declined as the plants matured, but both pathogens were detectable for at least 21 days . Survival of the pathogen was reduced in unautoclaved soil and amended soil, suggesting competition from indigenous epiphytes from the soil . Enterobacter asburiae was isolated from soil-grown A . thaliana and shown to be effective at suppressing epiphytic growth of both pathogens under gnotobiotic conditions . Seed and chaff harvested from contaminated plants were occasionally contaminated . The rate of recovery of S . enterica and E . coli O157:H7 from seed varied from undetectable to 19% of the seed pools tested, depending on the method of inoculation . Seed contamination by these pathogens was undetectable in the presence of the competitor, Enterobacter asburiae . Sampling of 74 pools of chaff indicated a strong correlation between contamination of the chaff and seed (P = 0.025) . This suggested that contamination of the seed occurred directly from contaminated chaff or by invasion of the flower or silique . However, contaminated seeds were not sanitized by extensive washing and chlorine treatment, indicating that some of the bacteria reside in a protected niche on the seed surface or under the seed coat.

Appl Environ Microbiol, 2003 Aug, 69(8), 4697 - 705
Rapid detection of meat spoilage by measuring volatile organic compounds by using proton transfer reaction mass spectrometry; Mayr D et al.; The evolution of the microbial spoilage population for air- and vacuum-packaged meat (beef and pork) stored at 4 degrees C was investigated over 11 days . We monitored the viable counts (mesophilic total aerobic bacteria, Pseudomonas spp., Enterobacteriaceae, lactic acid bacteria, and Enterococcus spp.) by the microbiological standard technique and by measuring the emission of volatile organic compounds (VOCs) with the recently developed proton transfer reaction mass spectrometry system . Storage time, packaging type, and meat type had statistically significant (P < 0.05) effects on the development of the bacterial numbers . The concentrations of many of the measured VOCs, e.g., sulfur compounds, largely increased over the storage time . We also observed a large difference in the emissions between vacuum- and air-packaged meat . We found statistically significant strong correlations (up to 99%) between some of the VOCs and the bacterial contamination . The concentrations of these VOCs increased linearly with the bacterial numbers . This study is a first step toward replacing the time-consuming plate counting by fast headspace air measurements, where the bacterial spoilage can be determined within minutes instead of days.

Appl Environ Microbiol, 2003 Aug, 69(8), 4583 - 94
Microbial quality and direct PCR identification of lactic acid bacteria and nonpathogenic Staphylococci from artisanal low-acid sausages; Aymerich T et al.; Detection of six species of lactic acid bacteria and six species of gram-positive catalase-positive cocci from low-acid fermented sausages (fuets and chorizos) was assessed by species-specific PCR . Without enrichment, Lactobacillus sakei and Lactobacillus curvatus were detected in 11.8% of the samples, and Lactobacillus plantarum and Staphylococcus xylosus were detected in 17.6% . Enriched samples allowed the detection of L . sakei and S . xylosus in all of the samples (100%) and of Enterococcus faecium in 11.8% of the sausages . The percentages of L . curvatus, L . plantarum, Staphylococcus carnosus, and Staphylococcus epidermidis varied depending on the sausage type . L . curvatus was detected in 80% of fuets and in 57% of chorizos . L . plantarum was found in 50% of fuets and 100% of chorizos . S . epidermidis was detected in only 11.8% of fuets, and S . carnosus was detected in only 5.9% of chorizos . Lactococcus lactis, Staphylococcus warneri, and Staphylococcus simulans were not detected in any sausage type . From a microbiological point of view, 70.6% of the samples could be considered of high quality, as they had low counts of Enterobacteriaceae and did not contain any of the food-borne pathogens assayed.

New Microbiol, 2003 Jul, 26(3), 257 - 62
Prevalence of extended-spectrum beta-lactamases produced by nosocomial isolates of Enterobacteriaceae in Trakya University Hospital, Turkey; Akata F et al.; The prevalence of extended-spectrum beta-lactamase (ESBL) production by 194 nosocomial isolates of Enterobacteriacea recovered from 1995 to 1999 was investigated . The ESBL production was determined by the double-disk synergy test and was confirmed by the E-test ESBL strip . Twenty-three isolates (21 Klebsiella pneumoniae, one Escherichia coli, one Providencia rettgeri) were found as ESBL-producers (11.8%) . These isolates were also usually resistant to non-betalactam antibiotics . Most of them contained a beta-lactamase with a pI of 7.6 . All the strains conjugally transferred their ESBLs to recipient E . coli . Contrary to others, ESBL-producing K . pneumoniae strains isolated in 1999 were resistant to ciprofloxacin, and had the identical plasmid profiles suggestive of an outbreak . Ciprofloxacin resistance in these strains could not be transferred . In conclusion, K . pneumoniae was the main ESBL-producing species among nosocomial isolates of Enterobacteriacae in our hospital.

Am J Kidney Dis, 2003 Aug, 42(2), 342 - 9
Levofloxacin pharmacokinetics in ESRD and removal by the cellulose acetate high performance-210 hemodialyzer; Sowinski KM et al.; BACKGROUND: No published data are available describing the pharmacokinetics of intravenous levofloxacin in patients with end-stage renal disease (ESRD) . Objectives of this study are to determine the pharmacokinetics and dialytic clearance of levofloxacin and develop dosing strategies in these patients . METHODS: Eight noninfected subjects receiving long-term thrice-weekly hemodialysis, with no measurable residual renal function, were administered intravenous levofloxacin, 250 mg, over 1 hour after a scheduled hemodialysis session . Blood samples were collected serially during the interdialytic period, during the next intradialytic period, and immediately after the next hemodialysis session . Serum concentrations of levofloxacin were determined by high-performance liquid chromatography . Differential equations describing a 2-compartment open-infusion pharmacokinetic model were fit to each individual subject's serum concentration-time data by iterative nonlinear weighted least-squares regression analysis using Adapt II (Biomedical Simulations Resource, University of Southern California, Los Angeles, CA) . Ratios of maximum serum concentration (C(max)) to minimum inhibitory concentration (MIC) were calculated for common respiratory pathogens by using MIC for 90% of isolates (MIC90) data from published studies . RESULTS: All subjects completed the study, and no adverse events were reported . Median systemic clearance, volume of distribution at steady state, elimination half-life, and C(max) were 37.0 mL/min (range, 12.8 to 42.7 mL/min), 103.3 L (range, 39.8 to 139.3 L), 34.4 hours (range, 28.4 to 39.3 hours), and 5.2 microg/mL (range, 4.1 to 11.3 microg/mL), respectively . Median dialytic clearance and levofloxacin reduction ratios were 84.4 mL/min (range, 61.8 to 107.6 mL/min) and 0.244 (range, 0.181 to 0.412), respectively . Median C(max)-MIC90 ratios were 10 or greater for Haemophilus influenzae, Moraxella catarrhalis, Enterobacter cloacae, and Klebsiella pneumoniae, approximately 5 for Streptococcus pneumoniae, and less than 1 for Pseudomonas aeruginosa . CONCLUSION: The administration of levofloxacin to patients with ESRD as 500 mg initially, followed by 250 mg every 48 hours, will provide adequate C(max)-MIC ratios after the first and subsequent doses for most patients with respiratory tract infections caused by organisms with levofloxacin MICs of 1 microg/mL or less.

Eur J Biochem, 2003 Aug, 270(16), 3469 - 76
Cause of mortality in insects under severe stress; Matsumoto H et al.; Mortality in the host armyworm larvae Pseudaletia separata parasitized by the parasitic wasp Cotesia kariyai was dramatically increased when they were simultaneously infected by the entomopathogen Serratia marcescens . Previous studies have shown that this strong insecticidal effect is due to a metalloprotease-like insecticide (MPLI) released from S . marcescens enterobacter . This study was conducted to elucidate the exact cause of the mortality resulting from MPLI . Injection of MPLI caused a sharp increase in hemolymph dopamine concentration followed by elevated levels of brain dopamine in armyworm larvae . {3H}Dopamine injected into the hemocoel, was incorporated into the brains of MPLI-injected larvae to a level eight times greater than in BSA-injected control larvae . Transmission electron microscopy showed an obvious decrease in thickness and density of the brain sheath in insects injected with MPLI . This was probably due to the MPLI-induced elevation of hemocyte metalloprotease activities . Further, electron microscopic and TUNEL staining analyses showed a significant increase in apoptotic cells in the brain 12 h after the injection . Injection of 3-iodotyrosine (a tyrosine hydroxylase inhibitor) before MPLI completely prevented the increase in hemolymph dopamine in test larvae and their following death . From these observations, we conclude that MPLI-injected larvae may have suffered mortal damage through increased apoptosis of brain cells caused by an influx of dopamine from the hemolymph.

Bioresour Technol, 2003 Nov, 90(2), 139 - 43
Synergetic effect of gamma irradiation and moisture content on decontamination of sewage sludge; Al-Bachir M et al.; Samples of concentrated municipal sewage sludge, stored for 2, 4 and 6 months, with moisture contents of 2%, 20%, 40%, 60%, and 80% were exposed to doses of 0, 1, 2, 3, 4 and 5 kilogray (kGy) of gamma irradiation . Immediately after irradiation, total microbial count and bacterial pathogens in sewage sludge were determined . The results indicated that in all tested sewage sludge samples, bacterial pathogens including Enterobacter sp., Klebsiella sp., Salmonella sp., and Escherichia coli were initially detected . All doses of gamma irradiation reduced the total counts of microorganisms . D(10) of total count decreased with increase in the moisture content of the sewage sludge . The lowest lethal dose for tested bacterial pathogens was 5 kGy in air dried sewage sludge . In addition for wet sewage sludge having more than 40% moisture, the lethal dose was 1 kGy, for samples taken at different storage periods 2, 4 and 6 months, and therefore the cost per unit could be decreased to half when wet sewage sludge (about 50% moisture) was used.

Res Microbiol, 2003 Jul-Aug, 154(6), 425 - 31
Genetic engineering of Enterobacter aerogenes with the Vitreoscilla hemoglobin gene: cell growth, survival, and antioxidant enzyme status under oxidative stress; Geckil H et al.; Hemoglobins in unicellular organisms, like the one here in the bacterium Vitreoscilla, have greater chemical reactivity than their homologues in multicellular organisms . They can catalyze redox reactions and may protect cells against oxidative stress . The ability of Vitreoscilla hemoglobin to complement deficiencies of terminal cytochrome oxidases in Escherichia coli also suggests that this hemoglobin can receive electrons during respiration . In this study, a recombinant strain of Enterobacter aerogenes engineered to produce the Vitreoscilla Hb was investigated with regard to its susceptibility to oxidative stress . The culture response to oxidative stress produced by exogenously applied hydrogen peroxide was characterized in terms of cell growth, survival and the activities of two key antioxidant enzymes (catalase and superoxide dismutase) . The influence of the physiological state of the cells and different media upon these culture dynamics was determined . Results showed that the hemoglobin-expressing strain is quite distinct in terms of growth/survival properties and activity of antioxidant enzymes from that of non-hemoglobin counterparts.

Am J Health Syst Pharm, 2003 Jul 15, 60(14), 1440 - 6
Enterobacter cloacae bloodstream infections in pediatric patients traced to a hospital pharmacy; Selenic D et al.; The sources of an outbreak of Enterobacter cloacae bloodstream infections in a pediatric hospital were investigated, as were the risk factors for acquiring the infection: Two retrospective case-control studies were conducted . The study sample included all patients admitted to the general pediatric wards from February 5 through March 30, 2001, who had a positive blood culture for E . cloacae . Pediatric ward and pharmacy infection-control practices were reviewed, personnel and environmental cultures were obtained, and pulsed-field gel electrophoresis (PFGE) molecular typing of the bloodstream isolates was conducted . Four subjects were identified . These infants were more likely than control patients to receive i.v . ranitidine (p < 0.01) . Among patients receiving i.v . ranitidine, subjects were more likely than controls to receive i.v . ranitidine prepared by a pharmacist . No environmental or personnel cultures yielded E . cloacae . Patients' E . cloacae isolates had four different PFGE patterns, suggesting environmental rather than point-source contamination . Ranitidine multidose vials were kept connected to an automatic compounding machine for up to 48 hours at room temperature after the first dose was drawn, contrary to manufacturer recommendations . Further, preparation of ranitidine infusions was not conducted in accordance with recommendations for risk level 2 sterile i.v . products . The use of contaminated ranitidine multidose vials was the most likely cause of an outbreak of E . cloacae . However, a combination of other factors such as inadequate hand-washing techniques, presence of E . cloacae in the environment, noncompliance with guidelines for the preparation of sterile infusions and medications, and a susceptible population may have contributed to the infections.

Mol Microbiol, 2003 Aug, 49(4), 1031 - 41
Microcin E492 antibacterial activity: evidence for a TonB-dependent inner membrane permeabilization on Escherichia coli; Destoumieux-Garzon D et al.; The mechanism of action of microcin E492 (MccE492) was investigated for the first time in live bacteria . MccE492 was expressed and purified to homogeneity through an optimized large-scale procedure . Highly purified MccE492 showed potent antibacterial activity at minimal inhibitory concentrations in the range of 0.02-1.2 microM . The microcin bactericidal spectrum of activity was found to be restricted to Enterobacteriaceae and specifically directed against Escherichia and Salmonella species . Isogenic bacteria that possessed mutations in membrane proteins, particularly of the TonB-ExbB-ExbD complex, were assayed . The microcin bactericidal activity was shown to be TonB- and energy-dependent, supporting the hypothesis that the mechanism of action is receptor mediated . In addition, MccE492 depolarized and permeabilized the E . coli cytoplasmic membrane . The membrane depolarization was TonB dependent . From this study, we propose that MccE492 is recognized by iron-siderophore receptors, including FepA, which promote its import across the outer membrane via a TonB- and energy-dependent pathway . MccE492 then inserts into the inner membrane, whereupon the potential becomes destabilized by pore formation . Because cytoplasmic membrane permeabilization of MccE492 occurs beneath the threshold of the bactericidal concentration and does not result in cell lysis, the cytoplasmic membrane is not hypothesized to be the sole target of MccE492.

Am J Infect Control, 2003 Aug, 31(5), 280 - 7
Spectrum of microbes and antimicrobial resistance in a surgical intensive care unit, Barbados; Hariharan S et al.; BACKGROUND: To survey the epidemiologic findings of infections and antibiotic resistance patterns in the surgical intensive care unit (ICU) of a tertiary care university teaching hospital . METHODS: The microbiologic culture-sensitivity reports of patients admitted to a surgical ICU were prospectively studied for 6 months each of 3 consecutive years . The antibiotic usage for these patients also was studied concurrently . Reports from general surgical wards for 6 months of 1 year also were analyzed for comparison . The common specimens assayed microbiologically were tracheal aspirate, urine, blood, wound swabs, invasive catheter tips, and screening swabs for methicillin-resistant Staphylococcus aureus . RESULTS: The organisms reported were Enterobacteriaceae, Pseudomonas species, S aureus, and enterococci . Organisms were highly resistant to amoxicillin and first-generation cephalosporins because of the wide use of these drugs in the hospital . Pseudomonas species showed a 25% increase in resistance to piperacillin-tazobactam and an 18% increase to ciprofloxacin, which was correlated with the increased use of these antimicrobial agents (82% and 200% increases, respectively) in the unit during the 3 years . There was no increase in the resistance to ceftazidime because it is used less often . The resistance to ciprofloxacin, piperacillin-tazobactam, and ceftazidime was significantly greater in the ICU than in the general surgical wards in the same study period . CONCLUSIONS: The study provided data of antimicrobial resistance in a developing country with tourism as the main industry for epidemiologic comparison with other countries.

Infect Control Hosp Epidemiol, 2003 Jul, 24(7), 490 - 4
Molecular epidemiology of systemic infection caused by Enterobacter cloacae in a high-risk neonatal intensive care unit; Kuboyama RH et al.; OBJECTIVE: To investigate the molecular epidemiology of systemic nosocomial infections caused by Enterobacter cloacae . SETTING: Neonatal intensive care unit (NICU) of a tertiary-care university hospital . PATIENTS: Forty-two high-risk neonates with systemic infections caused by E . cloacae . METHODS: From 1995 to 1997, the variables associated with death in these patients were evaluated . The molecular epidemiology of the strains responsible for the systemic infections, and 14 unrelated strains, was studied using plasmid analysis and pulsed-field gel electrophoresis (PFGE) . RESULTS: The overall mortality rate for infection caused by E . cloacae was 34%, whereas the crude mortality rate during the study period was 8.12% (P < .001) . Gestational age (preterm neonates) and birth weight (small for gestational age) were not associated with a higher risk of death . Insertion of a venous catheter by dissection of a peripheral vein was the only invasive procedure related to death (P = .016) in this study . A molecular analysis showed that three outbreaks, each occurring in a different year, were caused by strains with distinctive DNA profiles . Only one outbreak was identified by the infection control service, in the NICU . Plasmid analysis and PFGE showed similar ability to discriminate control strains from the E . cloacae strains isolated from the neonates . CONCLUSIONS: Systemic infections caused by E . cloacae in our NICU were associated with a high mortality rate and occurred as small, unrecognized outbreaks . These results may not be generalizable because the data were from a single center.

Avian Dis, 2003 Apr-Jun, 47(2), 247 - 53
Reducing airborne pathogens and dust in commercial hatching cabinets with an electrostatic space charge system; Mitchell BW et al.; Commercial hatcheries typically infuse hydrogen peroxide or formaldehyde gas into hatching cabinets to reduce airborne pathogens that may lead to disease transmission during the hatch . A nonchemical option, an electrostatic space charge system (ESCS), was customized for full-sized commercial hatching cabinets and was tested extensively in broiler hatcheries . The ESCS cleans air by transferring a strong negative electrostatic charge to dust and microorganisms that are aerosolized during the hatch and collecting the charged particles on grounded plates or surfaces . In studies with three poultry companies, the ESCS resulted in significant (P < 0.0001) reductions of airborne dust of 77%-79%, in Enterobacteriaceae and fungus levels not significantly different (P > or = 0.05) from those with formaldehyde, and in 93%-96% lower Enterobacteriaceae than with no treatment or with hydrogen peroxide treatment (P < 0.01) . The ESCS significantly (P < 0.05) reduced airborne Salmonella by 33%-83% compared with no treatment or hydrogen peroxide treatment . Results of this study suggest that the ESCS is a viable alternative to chemical treatment for reducing airborne pathogens in full-sized commercial hatchers, and it also provides dust control and containment, which should be helpful in reducing cross contamination and loading of ventilation ducts within different areas of the hatchery.

Eur J Immunol, 2003 Aug, 33(8), 2149 - 59
Caspase-dependent and -independent apoptosis of mast cells induced by withdrawal of IL-3 is prevented by Toll-like receptor 4-mediated lipopolysaccharide stimulation; Yoshikawa H et al.; IL-3-dependent mucosal-like mast cells undergo apoptosis upon withdrawal of IL-3 . Generally, the apoptosis is mediated by the activation of caspases and inhibited by addition of the pan-caspase inhibitors z-VAD-FMK or BOC-D-FMK . However, DNA fragmentation, a typical characteristic of apoptosis, is not inhibited by z-VAD-FMK or BOC-D-FMK in mast cell apoptosis . In this study, we demonstrate that the apoptosis of mast cells is mediated by both caspase-dependent and -independent mechanisms . The caspase-independent apoptosis is mediated by the translocation of endonuclease G from mitochondria into nuclei . Withdrawal of IL-3 caused down-regulation of Bcl-xL, resulting in a drop in mitochondrial membrane transition potential followed by the release of cytochrome c and endonuclease G from mitochondria . However, stimulation of mast cells through Toll-like receptor 4 (TLR4) by lipopolysaccharide prevented mast cell apoptosis by inducing expression of Bcl-xL . Moreover, the activation of mast cells by LPS is enhanced in the presence of IFN-gamma, which up-regulates the expression of cell surface TLR4 . Taken together, these observations provide evidence that mast cells play important roles not only in allergic reactions but also in innate immunity recognizing enterobacteria through TLR4, and are regulated differently from allergic inflammation by Th1 cytokines.

Clin Infect Dis, 2003 Aug 1, 37(3), 344 - 50 Epub 2003 Jul 17.
Relationships between patient- and institution-specific variables and decreased antimicrobial susceptibility of Gram-negative pathogens; Bhavnani SM et al.; The identification of patients infected with antibiotic-resistant strains of bacteria for inclusion in clinical trials remains a serious challenge for the future development of agents for use against such infections . To identify patient- and institution-specific factors predictive of reduced susceptibility of Enterobacter species, Pseudomonas aeruginosa, and Klebsiella pneumoniae to cefepime, ciprofloxacin, and piperacillin-tazobactam, 5 years (1997-2001) of North American surveillance data were analyzed . The relationship between minimum inhibitory concentration (MIC) values for each organism-agent pair and patient- and institution-specific variables was analyzed using multivariable general linear modeling . The variables most commonly associated with decreases in susceptibility were duration of hospital stay before pathogen isolation, hospital size, primary diagnosis, and medical service . Combinations of these variables were associated with increases in observed MIC90 values of as much as 16-32-fold . Our findings demonstrate a relationship between MIC and certain patient- and institution-specific variables . Such data should be considered in the design of clinical trials directed at the study of resistant pathogens.

Eur J Clin Microbiol Infect Dis, 2003 Aug, 22(8), 479 - 85 Epub 2003 Jul 18.
Evaluation of the BD Phoenix automated identification and susceptibility testing system in clinical microbiology laboratory practice; Stefaniuk E et al.; The Phoenix Automated Microbiology System (BD Biosciences, USA) is a new, fully automated system for the rapid identification and antimicrobial susceptibility testing of gram-positive and gram-negative bacteria . The objective of this study was to evaluate the quality of performance of the Phoenix system in the identification and antimicrobial susceptibility testing of 260 gram-negative ( n=174) and gram-positive ( n=86) isolates collected from Polish hospitals in recent years . Two Phoenix panel types for identification/antimicrobial susceptibility testing, NMIC/ID-5 for gram-negative rods and PMIC/ID-4 for gram-positive cocci, were used in the analysis according to the manufacturer's recommendations . The results produced by the system were compared with data obtained by reference or conventional microbiological methods . A high rate of agreement between the Phoenix and the conventional methods was observed for identification, ranging from 100% for gram-positive cocci to 96.0% for gram-negative nonfermenters and 92.5% for members of the family Enterobacteriaceae . Similarly, a high level of agreement characterized the antimicrobial susceptibility data obtained with the Phoenix and by the agar dilution method (2,361 test results) . For staphylococci, enterococci and Enterobacteriaceae, the methods were 100% concordant in determining the category of susceptibility of isolates to the majority of the antimicrobial agents tested . A category agreement value of below 90% was found for the susceptibility of enterococci and gram-negative nonfermenters to ciprofloxacin (84.6% and 88.5%, respectively) and for susceptibility of Stenotrophomonas maltophilia to trimethoprim-sulfamethoxazole (80.0%).

Biochem J, 2003 Jul 15, 373(Pt 2), 515 - 22
Relationship between bacterial virulence and nucleotide metabolism: a mutation in the adenylate kinase gene renders Yersinia pestis avirulent; Munier-Lehmann H et al.; Nucleoside monophosphate kinases (NMPKs) are essential catalysts for bacterial growth and multiplication . These enzymes display high primary sequence identities among members of the family Enterobacteriaceae . Yersinia pestis, the causative agent of plague, belongs to this family . However, it was previously shown that its thymidylate kinase (TMPKyp) exhibits biochemical properties significantly different from those of its Escherichia coli counterpart {Chenal-Francisque, Tourneux, Carniel, Christova, Li de la Sierra, Barzu and Gilles (1999) Eur . J . Biochem . 265, 112-119} . In this work, the adenylate kinase (AK) of Y . pestis (AKyp) was characterized . As with TMPKyp, AKyp displayed a lower thermodynamic stability than other studied AKs . Two mutations in AK (Ser129Phe and Pro87Ser), previously shown to induce a thermosensitive growth defect in E . coli, were introduced into AKyp . The recombinant variants had a lower stability than wild-type AKyp and a higher susceptibility to proteolytic digestion . When the Pro87Ser substitution was introduced into the chromosomal adk gene of Y . pestis, growth of the mutant strain was altered at the non-permissive temperature of 37 degree C . In virulence testings, less than 50 colony forming units (CFU) of wild-type Y . pestis killed 100% of the mice upon subcutaneous infection, whereas bacterial loads as high as 1.5 x 10(4) CFU of the adk mutant were unable to kill any animals.

Drugs Today (Barc), 2000 Apr, 36(4), 215 - 27
The microbiology of moxifloxacin; Garcia-Rodriguez JA et al.; Moxifloxacin is a new group IV 8-methoxyquinolone . It is slightly less active than ciprofloxacin against enterobacteria and much less effective against P . aeruginosa . However, moxifloxacin is clearly better than ciprofloxacin in treating atypical microorganisms and especially anaerobic bacteria and aerobic Gram-positive cocci, including methicillin-resistant Staphylococcus aureus and penicillin-resistant Streptococcus pneumoniae . In recent years there has been an increase in the resistance of some respiratory pathogens to beta-lactam and macrolide antibiotics . Bearing in mind that moxifloxacin is well tolerated, its microbiological properties and pharmacokinetic characteristics mean that it will undoubtedly be useful in treating certain infections, particularly community-acquired respiratory infections, hospital-acquired respiratory infections caused by aerobic Gram-positive cocci, infections caused by anaerobic bacteria and skin infections . Studies have shown that moxifloxacin is effective and well tolerated in all of these conditions.

Antimicrob Agents Chemother, 2003 Aug, 47(8), 2572 - 8
Extended-spectrum beta-lactamases in Ireland, including a novel enzyme, TEM-102; Morris D et al.; Organisms producing extended-spectrum beta-lactamases (ESBLs) have been reported in many countries, but there is no information on the prevalence of ESBL-producing members of the family Enterobacteriaceae in Ireland . A total of 925 isolates of ampicillin-resistant members of the Enterobacteriaceae were received from six hospitals in Ireland over a 3-year period from September 1996 to September 1999 . Isolates were screened for ESBL production by the double-disk diffusion (DDD) method . DDD-positive isolates that were (i) confirmed as ESBL producers by National Committee for Clinical Laboratory Standards (NCCLS) confirmatory testing and (ii) susceptible to cefoxitin by disk diffusion were considered ESBL producers . By these criteria, 27 (3%) of the ampicillin-resistant members of the Enterobacteriaceae studied were categorized as ESBL producers . Molecular typing suggested that some intra- and interhospital spread of ESBL-producing isolates had occurred . DNA sequencing of amplified bla(TEM) and bla(SHV) genes resulted in the detection of a novel bla(TEM) ESBL gene, bla(TEM-102) in two isolates (Klebsiella pneumoniae and Enterobacter cloacae) received from the same hospital but isolated from different patients . The study suggests dissemination of ESBL-producing bacteria within the health care system in Ireland and emphasizes the need for measures to control such spread.

Antimicrob Agents Chemother, 2003 Aug, 47(8), 2565 - 71
Plasmid-mediated high-level resistance to aminoglycosides in Enterobacteriaceae due to 16S rRNA methylation; Galimand M et al.; A self-transferable plasmid of ca . 80 kb, pIP1204, conferred multiple-antibiotic resistance to Klebsiella pneumoniae BM4536, which was isolated from a urinary tract infection . Resistance to beta-lactams was due to the bla(TEM1) and bla(CTX-M) genes, resistance to trimethroprim was due to the dhfrXII gene, resistance to sulfonamides was due to the sul1 gene, resistance to streptomycin-spectinomycin was due to the ant3"9 gene, and resistance to nearly all remaining aminoglycosides was due to the aac3-II gene and a new gene designated armA (aminoglycoside resistance methylase) . The cloning of armA into a plasmid in Escherichia coli conferred to the new host high-level resistance to 4,6-disubstituted deoxystreptamines and fortimicin . The deduced sequence of ArmA displayed from 37 to 47% similarity to those of 16S rRNA m(7)G methyltransferases from various actinomycetes, which confer resistance to aminoglycoside-producing strains . However, the low guanine-plus-cytosine content of armA (30%) does not favor an actinomycete origin for the gene . It therefore appears that posttranscriptional modification of 16S rRNA can confer high-level broad-range resistance to aminoglycosides in gram-negative human pathogens.

Int J Food Microbiol, 2003 Aug 25, 85(3), 281 - 91
Characterization of an Escherichia coli O157:H7 marR mutant; Yaron S et al.; One mechanism for generation of multiple antibiotic resistance in enteric bacteria involves the global regulatory system marRAB . The operon, when induced, encodes for resistance to structurally and functionally unrelated antibiotics . Exposure of Escherichia coli O157:H7 to increasing levels of chloramphenicol (CHL) resulted in survival of mutants that were resistant to the inducing agent and to tetracycline (TET), nalidixic acid (NAL), and ciprofloxacin (CIP) . A mutant (RU122) that lacks MarR, the transcriptional repressor of the multiple antibiotic resistance (mar) operon, served as a genetic tool to study the role of MarR in growth of E . coli O157:H7 . No significant difference (P>0.05) was observed in growth curves of the wild-type or the mutant under the conditions examined (rich and minimal media, acidic conditions, and temperatures from 24 to 42 C) . A preconditioned mutant (indRU122; cultured for 17 h in Luria-Bertani (LB) containing chloramphenicol and then examined) exhibited greater growth under all treatments tested compared to the mutant . marCRAB of E . coli O157:H7 was sequenced and compared to other known mar sequences to determine divergence from other bacteria (Salmonella, Klebsiella, and Enterobacter).

Int J Food Microbiol, 2003 Aug 25, 85(3), 259 - 67
Effects of treatment with lysozyme and nisin on the microflora and sensory properties of commercial pork; Nattress FM et al.; A mixture of lysozyme and nisin at a ratio of 3:1 (w/w) and at a surface concentration of approximately 260 microg/cm2 was effective in controlling the growth of lactic acid bacteria, lactic acid bacteria able to grow in the presence of acetate and Brochothrix thermosphacta on naturally contaminated pork loins that were stored in vacuum packages at 2 degrees C for up to 6 weeks . When loins were removed, cut into chops, and displayed in a retail display case, the efficacy of the antimicrobial mixture decreased with increasing display time . At most sampling times, bacterial numbers were lower in treated samples than in untreated samples . The numbers of Enterobacteriaceae were higher in treated samples than in untreated samples . The growth of Enterobacteriaceae may have been reduced as a result of antimicrobial activity of the lactic acid bacteria because when the growth of lactic acid bacteria was inhibited by the antimicrobial treatment, the Enterobacteriaceae were able to grow to higher numbers . Sensory evaluation of the loins showed no difference between treated and untreated samples, but aerobically displayed chops treated with antimicrobial had more prevalent off-odours and reduced odour acceptability than untreated samples.

BMC Evol Biol . 2003 Jul 23;3(1):18.
Phylogenetic analysis of bacterial and archaeal arsC gene sequences suggests an ancient, common origin for arsenate reductase; Jackson CR et al.; BACKGROUND: The ars gene system provides arsenic resistance for a variety of microorganisms and can be chromosomal or plasmid-borne . The arsC gene, which codes for an arsenate reductase is essential for arsenate resistance and transforms arsenate into arsenite, which is extruded from the cell . A survey of GenBank shows that arsC appears to be phylogenetically widespread both in organisms with known arsenic resistance and those organisms that have been sequenced as part of whole genome projects . RESULTS: Phylogenetic analysis of aligned arsC sequences shows broad similarities to the established 16S rRNA phylogeny, with separation of bacterial, archaeal, and subsequently eukaryotic arsC genes . However, inconsistencies between arsC and 16S rRNA are apparent for some taxa . Cyanobacteria and some of the gamma-Proteobacteria appear to possess arsC genes that are similar to those of Low GC Gram-positive Bacteria, and other isolated taxa possess arsC genes that would not be expected based on known evolutionary relationships . There is no clear separation of plasmid-borne and chromosomal arsC genes, although a number of the Enterobacteriales (gamma-Proteobacteria) possess similar plasmid-encoded arsC sequences . CONCLUSION: The overall phylogeny of the arsenate reductases suggests a single, early origin of the arsC gene and subsequent sequence divergence to give the distinct arsC classes that exist today . Discrepancies between 16S rRNA and arsC phylogenies support the role of horizontal gene transfer (HGT) in the evolution of arsenate reductases, with a number of instances of HGT early in bacterial arsC evolution . Plasmid-borne arsC genes are not monophyletic suggesting multiple cases of chromosomal-plasmid exchange and subsequent HGT . Overall, arsC phylogeny is complex and is likely the result of a number of evolutionary mechanisms.

Mar Biotechnol (NY), 2003 Mar-Apr, 5(2), 185 - 93
Tolerance to various toxicants by marine bacteria highly resistant to mercury; De J et al.; Bacteria highly resistant to mercury isolated from seawater and sediment samples were tested for growth in the presence of different heavy metals, pesticides, phenol, formaldehyde, formic acid, and trichloroethane to investigate their potential for growth in the presence of a variety of toxic xenobiotics . We hypothesized that bacteria resistant to high concentrations of mercury would have potential capacities to tolerate or possibly degrade a variety of toxic materials and thus would be important in environmental pollution bioremediation . The mercury-resistant bacteria were found to belong to Pseudomonas, Proteus, Xanthomonas, Alteromonas, Aeromonas, and Enterobacteriaceae . All these environmental bacterial strains tolerant to mercury used in this study were capable of growth at a far higher concentration (50 ppm) of mercury than previously reported . Likewise, their ability to grow in the presence of toxic xenobiotics, either singly or in combination, was superior to that of bacteria incapable of growth in media containing 5 ppm mercury . Plasmid-curing assays done in this study ascertained that resistance to mercury antibiotics, and toxic xenobiotics is mediated by chromosomally borne genes and/or transposable elements rather than by plasmids.

Protein Sci, 2003 Aug, 12(8), 1633 - 45
Identification of residues critical for catalysis in a class C beta-lactamase by combinatorial scanning mutagenesis; Goldberg SD et al.; Despite their clinical importance, the mechanism of action of the class C beta-lactamases is poorly understood . In contrast to the class A and class D beta-lactamases, which contain a glutamate residue and a carbamylated lysine in their respective active sites that are thought to serve as general base catalysts for beta-lactam hydrolysis, the mechanism of activation of the serine and water nucleophiles in the class C enzymes is unclear . To probe for residues involved in catalysis, the class C beta-lactamase from Enterobacter cloacae P99 was studied by combinatorial scanning mutagenesis at 122 positions in and around the active site . Over 1000 P99 variants were screened for activity in a high-throughput in vivo antibiotic resistance assay and sequenced by 96-capillary electrophoresis to identify residues that are important for catalysis . P99 mutants showing reduced capability to convey antibiotic resistance were purified and characterized in vitro . The screen identified an active-site hydrogen-bonding network that is key to catalysis . A second cluster of residues was identified that likely plays a structural role in the enzyme . Otherwise, residues not directly contacting the substrate showed tolerance to substitution . The study lends support to the notion that the class C beta-lactamases do not have a single residue that acts as the catalytic general base . Rather, catalysis is affected by a hydrogen-bonding network in the active site, suggesting a possible charge relay system.

Biomedica, 2003 Jun, 23(2), 134 - 40
{Guides for rational use of B-lactam antibiotics:resistance mechanism and clinical interpretation}; Arias CA et al.; beta-lactams are the antibiotic compounds most widely used against hospital and community acquired infections . However, resistance has emerged in both Gram-positive and Gram-negative bacteria, limiting their therapeutic efficacy . The choice of appropriate treatment depends on analysis of susceptibility data that indicates a specific mechanism of resistance . Correct interpretation of susceptibility tests permits a rational approach to the resistance problem and selection of alternatives for treatment . The laboratory must first be able to identify accurately microorganisms to the species level and then test a minimum of relevant antimicrobials . beta-lactam resistance in Enterobacteriaceae is mainly due to the production of plasmid or chromosomal encoded beta-lactamases . In Gram-negative non-fermenting bacteria, impermeability and efflux are relatively more important to the treatment selected . In Gram-positive bacteria, resistance mechanisms can involve changes in penicillin-binding proteins (PBPs), production of new PBPs or synthesis of beta-lactamases . The range of therapeutic options must be based on the current status of local resistance mechanisms.

Presse Med, 2003 May 24, 32(18), 839 - 42
{Two cases of severe community-acquired pleural pneumonia due to Streptococcus pyogenes}; Gantier F et al.; INTRODUCTION: The microorganisms incriminated in severe community-acquired pneumonia hospitalized in intensive care unit are the following: Streptococcus pneumoniae, enterobacteria isolated in aspiration-related pneumonia and less frequently intracellular bacteria in so-called atypical pneumonia (Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumophila) . CASE REPORTS: We report two cases of severe community-acquired pneumonia admitted in intensive care unit and due to Lancefield Group A beta hemolytic streptococcus (Streptococcus pyogenes) . Despite the increased incidence of invasive streptococcal infections, this microorganism still has a rare causative role in the pathogenesis of community-acquired pneumonia . The case reports concern two young patients without any significant medical history and with many clinical, radiological and microbiological similarities . However, the prognosis was not the same because of the way the initial management has been provided . DISCUSSION: Group A beta hemolytic streptococcus could be a causative microorganism of severe and possibly fulminating community-acquired pneumonia, even in young and healthy patients as is the case with pneumococcal infections . Medical history, clinical symptoms and radiological signs should be taken into account to evoke the diagnosis and to initiate antibiotherapy early, taking into account that this microorganism is sensitive to Penicillin G.

Rev Inst Med Trop Sao Paulo, 2003 May-Jun, 45(3), 119 - 23 Epub 2003 Jul 08.
Analysis of the clonal relationship among clinical isolates of Salmonella enterica serovar Infantis by different typing methods; Merino LA et al.; Salmonella Infantis has been the second most common serovar in Argentina in the last two years, being isolated mostly from paediatric hospitalised patients . In order to determine the clonal relationship among Salmonella Infantis strains, we examined 15 isolates from paediatric patient faeces in Argentina (12 geographically related and 3 geographically non-related) by using antimicrobial susceptibility, plasmid profiling, repetitive extragenic palindromic (REP) PCR, enterobacterial repetitive intergenic consensus (ERIC) PCR, and low-frequency restriction analysis of chromosomal DNA by pulsed field gel electrophoresis (PFGE) . Four Spanish strains were included as controls of clonal diversity in molecular techniques . Antibiotype and plasmid profile was not useful as epidemiological tools . PFGE and REP-PCR were able to discriminate between Argentinean and Spanish isolates of Salmonella Infantis allowing to detect genetically related strains in three different cities . This finding indicates that a possible spread of a clone of this serovar in the North-eastern Region of Argentina has taken place in 1998.

J Med Microbiol, 2003 Aug, 52(Pt 8), 697 - 703
Fitness cost of fluoroquinolone resistance in Salmonella enterica serovar Typhimurium; Giraud E et al.; High-level fluoroquinolone (FQ) resistance is still infrequent in salmonellae, compared with other pathogenic enterobacteria . Data provided in this work support the hypothesis that the mechanisms that confer high-level FQ resistance on salmonellae have a prohibitive fitness cost and may thus limit the emergence of highly resistant clones . In vitro mutants that were highly resistant to ciprofloxacin (MIC = 8 and 16 micro g ml(-1)) showed generation times 1.4- and 2-fold longer than their parent strains and were unable to colonize the gut of chickens . Electron microscopy showed an altered morphology for one of these mutants grown to stationary phase . Mutants selected in vivo and exhibiting intermediate resistance to ciprofloxacin (MIC = 2 micro g ml(-1)) also showed growth defects on solid media but had normal generation times in liquid culture and colonized the gut of chickens . After in vitro or in vivo passage in the absence of antibiotic selective pressure, partial reversals of the fitness cost were observed, which were associated with slight decreases in resistance to quinolones and other unrelated antibiotics, but were not linked to the loss of gyrA mutations.

J Bacteriol, 2003 Aug, 185(15), 4298 - 304
NhaR and RcsB independently regulate the osmCp1 promoter of Escherichia coli at overlapping regulatory sites; Sturny R et al.; Transcription of the Escherichia coli osmC gene is induced by several stress conditions . osmC is expressed from two overlapping promoters, osmCp1 and osmCp2 . The proximal promoter, osmCp2, is transcribed at the entry into the stationary phase by the sigma(s) sigma factor . The distal promoter, osmCp1, is activated by NhaR and RcsB . NhaR is a positive regulator of the LysR family and is known to be an activator of the nhaA gene encoding an Na(+)/H(+) antiporter . RcsB is the response regulator of the RcsCDB His-Asp phosphorelay signal transduction system . Genetic data indicated that activation of osmCp1 by both NhaR and RcsB requires the same short sequences upstream of the -35 region of the promoter . Accordingly, DNase I footprint analysis indicated that both activators protect an overlapping region close to the -35 box of the promoter and suggested that the regulatory effect is direct . Despite the overlap of the binding sites, each activator acts independent of the other and is specific for a particular stress . NhaR can stimulate osmCp1 in response to an osmotic signal even in the absence of RcsB . RcsB is responsible for the induction of osmCp1 by alteration of the cell envelope, even in the absence of NhaR . osmCp1 as an example of multiple-stress-responsive promoter is discussed in light of a comparison of the NhaR and RcsB target regions in the Enterobacteriaceae.

J Antimicrob Chemother, 2003 Aug, 52(2), 294 - 6 Epub 2003 Jul 15.
Susceptibility of Yersinia pestis to novel and conventional antimicrobial agents; Frean J et al.; OBJECTIVES: To determine the susceptibility of southern African strains of Yersinia pestis to novel as well as conventional antimicrobial agents . MATERIALS AND METHODS: The MICs of 28 strains of Yersinia pestis from a southern African plague focus were determined by agar dilution . RESULTS: The most active agents were cefditoren and the fluoroquinolones, both conventional and novel . The in vitro activity of macrolides was poor against this member of the Enterobacteriaceae . CONCLUSION: Further investigation of the novel quinolones olamufloxacin (HSR 903) and ABT 492 in animal models of plague would seem to be justified.

Life Sci, 2003 Aug 8, 73(12), 1527 - 35
Catecholamines and in vitro growth of pathogenic bacteria: enhancement of growth varies greatly among bacterial species; Belay T et al.; The purpose of this study was to examine the effects of catecholamines on in vitro growth of a range of bacterial species, including anaerobes . Bacteria tested included: Porphyromonas gingivalis, Bacteriodes fragilis, Shigella boydii, Shigella sonnie, Enterobacter Sp, and Salmonella choleraesuis . The results of the current study indicated that supplementation of bacterial cultures in minimal medium with norepinephrine or epinephrine did not result in increased growth of bacteria . Positive controls involving treatment of Escherichia coli with catecholamines did result in increased growth of that bacterial species . The results of the present study extend previous observations that showed differential capability of catecholamines to enhance bacterial growth in vitro.

Am J Vet Res, 2003 Jul, 64(7), 889 - 93
Population pharmacokinetics of marbofloxacin in aqueous humor after intravenous administration in dogs; Regnier A et al.; OBJECTIVE: To evaluate, by use of population pharmacokinetics, the disposition of marbofloxacin in the aqueous humor after IV administration in dogs and identify its potential usefulness in the prophylaxis and treatment of intraocular infection . ANIMALS: 63 dogs . METHODS: Dogs received a single dose of marbofloxacin (2 mg x kg(-1), IV) at various time intervals before cataract surgery . Aqueous humor and blood samples were collected at the beginning of surgery . Marbofloxacin concentrations were measured by high-pressure liquid chromatography . Data were analyzed with a nonlinear mixed-effect model and, by use of population pharmacokinetic parameters, the time course of aqueous humor concentration was simulated for single doses of 3, 4, and 5.5 mg x kg(-1) IV . Pharmacodynamic surrogate markers and measured aqueous humor concentrations were used to predict in vivo antimicrobial activity . RESULTS: A maximum marbofloxacin concentration of 0.41 +/- 0.17 microg x mL(-1) was reached in the aqueous humor 3.5 hours after IV administration . In the post-distributive phase, marbofloxacin disappeared from aqueous humor with a half-life of 780 minutes . The percentage penetration into the aqueous humor was 38% . Predictors of antimicrobial effects of marbofloxacin (2 mg x kg(-1), IV) indicated that growth of the enterobacteriaceae and certain staphylococcal species would be inhibited in the aqueous humor . Marbofloxacin administered IV at a dose of 5.5 mg x kg(-1) would be predicted to inhibit growth of Pseudomonas aeruginosa and all strains of staphylococci but would not eradicate streptococcal infections . CONCLUSIONS AND CLINICAL RELEVANCE: Marbofloxacin administered IV can penetrate the aqueous humor of canine eyes and may be suitable for prophylaxis or treatment of certain anterior chamber infections.

Clin Infect Dis, 2003 Jul 15, 37(2), 180 - 6 Epub 2003 Jul 09.
A hospitalwide intervention program to optimize the quality of antibiotic use: impact on prescribing practice, antibiotic consumption, cost savings, and bacterial resistance; Bantar C et al.; Several findings from Argentina provide compelling evidence of the need for more rational use of antimicrobial agents . Thus, a multidisciplinary antimicrobial treatment committee for the development of a hospital-wide intervention program was formed to optimize the quality of antibiotic use in hospitals . Four successive steps were developed during 6-month periods: baseline data collection, introduction of a prescription form, education, and prescribing control . Sustained reduction of drug consumption was shown during the study (R2=0.6885; P=.01) . Total cost savings was 913,236 US dollars . To estimate the consumption of cefepime and aminopenicillin-sulbactam in relation to that of the third-generation cephalosporins, 2 indices were calculated: Icfp and Iams, respectively . Decreasing resistance to ceftriaxone by Proteus mirabilis and Enterobacter cloacae proved to be associated with increasing Icfp . Decreasing rates of methicillin-resistant Staphylococcus aureus were related to increasing Iams . The present study indicates that a systematic program performed by a multidisciplinary team is a cost-effective strategy for optimizing antibiotic prescribing.

Clin Infect Dis, 2003 Jul 15, 37(2), 159 - 66 Epub 2003 Jul 09.
Nosocomial enterobacter meningitis: risk factors, management, and treatment outcomes; Parodi S et al.; Enterobacter species are increasingly a cause of nosocomial meningitis among neurosurgery patients, but risk factors for these infections are not well defined . A review of all adult patients hospitalized at the University of California-Los Angeles (UCLA) Medical Center during an 8-year period identified 15 postneurosurgical cases of Enterobacter meningitis (EM) . Cure was achieved in 14 cases (93%), and efficacy was similar for carbapenem- and cephalosporin-based treatment . A matched case-control study comparing 26 controls with 13 case patients hospitalized exclusively at the UCLA Medical Center found that external cerebrospinal fluid (CSF) drainage devices (odds ratio {OR}, 21.8; P=.001), isolation of Enterobacter species from a non-CSF culture (OR, 24.6; P=.002), and prolonged administration of antimicrobial drugs before the diagnosis of meningitis that were inactive in vitro against Enterobacter species (OR, 13.3; P=.008) were independent risk factors for EM . Despite favorable treatment outcomes, EM is a serious infection associated with Enterobacter species colonization or infection at other surgical sites, with selective antimicrobial pressure, and with invasive CNS devices.

J Hosp Infect, 2003 Jul, 54(3), 216 - 21
A preliminary evaluation of a new selective agar supplemented with desferrioxamine for detection of methicillin-resistant Staphylococcus aureus; Monsen T et al.; The aim of the present study was to evaluate the performance of two new selective screening agars, Colombia agar supplemented with 1000 mg/L desferrioxamine, 5 mg/L amphotericin B, 16 mg/L polymyxin B, and 2 mg/L methicillin (CMDAP agar) or 0.5 mg/L oxacillin (CODAP agar), for detection of methicillin-resistant Staphylococcus aureus (MRSA) . Both the CMDAP and the CODAP agar effectively inhibited growth of 151 isolates of coagulase-negative staphylococci (CoNS), 45 of Enterobacteriaceae and six Candida spp . examined . The sensitivity and specificity of the CMDAP and CODAP agars for detection of MRSA was calculated by comparing the growth of 52 MRSA with the inhibition of 74 mecA negative S . aureus and of 151 CoNS . The performance of the new agars was compared with four previously described MRSA screening agars . The sensitivity and specificity for detection of MRSA after incubation at 35 degrees C for 24 h was 0.94 and 0.91, respectively, for the CMDAP agar, 0.60 and 0.90 for the CODAP agar, 0.98 and 0.57 for methicillin aztreonam mannitol salt agar (MAMSA), 0.23 and 0.84 for oxacillin mannitol salt agar (OMSA), 0.48 and 0.76 for oxacillin Mueller-Hinton agar (OMHA) and 0.75 and 0.77 for lithium oxacillin mannitol salt agar (LOMSA) . Agars supplemented with desferrioxamine, CMDAP and CODAP, were more specific for detecting MRSA compared with agars not supplemented with desferrioxamine . The detection rate was higher for agars supplemented with methicillin than for agars supplemented with oxacillin.

FEMS Microbiol Lett, 2003 Jul 15, 224(1), 119 - 25
The glutamate-dependent acid resistance system of Escherichia coli and Shigella flexneri is inhibited in vitro by L-trans-pyrrolidine-2,4-dicarboxylic acid; Waterman SR et al.; Strains of Escherichia coli K-12, O157:H7, and Shigella flexneri grown to stationary phase in complex unbuffered media can survive for several hours at pH 2.5 . This stationary-phase acid resistance phenotype is dependent upon the alternate sigma factor sigmas and the supplementation of either glutamate or glutamine in the acidified media used for acid challenge . Acid resistance under these defined conditions can be inhibited by the glutamate analog L-trans-pyrrolidine-2,4-dicarboxylic acid which blocks uptake of glutamate/glutamine by selective inhibition . The gadC gene, encoding an inner membrane antiporter essential for the expression of acid resistance, could not be detected in other family members of the Enterobacteriacae.

Immunol Lett, 2003 Jul 3, 88(1), 21 - 6
Altered function of murine mast cells in response to lipopolysaccharide and peptidoglycan; Ikeda T et al.; Toll-like receptors (TLRs) recognize and signal the presence of bacterial components such as lipopolysaccharide (LPS) and peptidoglycan (PG) as a part of innate immunity . Our previous studies revealed that mast cells function as effector cells in the protection of mice against lethal enterobacterial infections . In this study, we examined both the gene expression of molecules involved in TLR signaling and the effects of LPS and PG in bone marrow-derived cultured mast cells (BMCMCs) . The mRNA expression of TLR2, TLR4 and TLR6 was detected in BMCMCs . CD14, MD-2 and MyD88, which are also involved in TLR pathway, were also expressed . Neither LPS nor PG affected degranulation in BMCMCs, but release of tumor necrosis factor increased slightly in response to LPS and PG . Both LPS and PG enhanced expression of pro-matrix metalloproteinase 9 (pro-MMP-9) in a dose-dependent manner, and DNA fragmentation was induced by LPS, but not by PG . These results suggest that mast cells are the targets of LPS and PG, and that the functions of these molecules produced exclusively by bacteria partly overlap, but are distinct.

Zhongguo Wei Zhong Bing Ji Jiu Yi Xue, 2003 Jan, 15(1), 38 - 41
{Initiation of systemic administration of antibiotics in treatment of invasive infection of burns}; Yang LY et al.; OBJECTIVE: To optimize the systemic antibiotics in the treatment of the invasive infection of burns based on the successive monitoring of bacterial species harvested from the burn wound and subeschar tissues and their resistance to antibiotics . METHODS: The data of bacterialogical monitoring of burn wound and subeschar tissues in our burn center from 1995 to 2000 were retrospectively analyzed, and the characteristics of distribution and resistance to antibiotics of 1 109 strains from the wound in 612 patients and subeschar tissues in 146 patients were compared statistically by dividing them into two periods, i.e . from 1995 to 1997 and 1998 to 2000, respectively . RESULTS: The percentage of Gram negative bacilli in identified strains was significantly higher than that of Gram positive cocci, and the majority of them were Pseudomonas and Enterobacteriaceae; Staphylococcus aureus comprised the majority of Gram positive cocci from 1998 to 2000, compared with the data collected in the period of from 1995 to 1997 . The resistance of the Gram negative bacilli to Cephalosporins and Amikacin was increasing while the resistance of Pseudomonas to Netilmicin was decreasing from 18.52% of the tested strains down to 5.83%, and the resistance of Enterobacteriaceae to it was increasing from 18.75% to 55.79% . In addition, the resistance of Staphylococcus aureus to Netilmicin was down from 28.13% to 4.70% . Enterobacteriaceae were still sensitive to Imipenem, while the resistance of Pseudomonas to it became higher than that in the period from 1995 to 1997 . CONCLUSION: The percentage of Gram negative bacilli in identified strains is significantly higher than that of Gram positive cocci and the pattern of their resistance to the antibiotics is changed meanwhile . Therefore, the choice of antibiotics for initial treatment of invasive infection in severe burns is a combination of Netilmicin and Imipenem, and, if Gram positive cocci is highly suspected, the first choice is Vancomycin.

Ann Agric Environ Med, 2003, 10(1), 93 - 100
Exposure to airborne Gram-negative bacteria, dust and endotoxin in paper factories; Prazmo Z et al.; Air samples for determination of the concentration of Gram-negative bacteria, dust and endotoxin were collected at 10 sites in 2 large pulp and paper mills (paper factories) located in northern Poland, of which one (plant "A") was an older type facility while the other (plant "B") was a modern, fully automated factory with an effective ventilatory system . In both factories paper was produced from wood chips derived mostly from Scots pine . The concentrations of Gram-negative bacteria in the air of examined factories were within a range of 11.0-310.0 cfu/m(3), being greatest in the old type factory "A" at the initial stages of production cycle comprising handling of chips and pulp production . The mean value for these sites (246.9 cfu/m(3)) was significantly greater (t-test, p < 0.01) compared to final stages of paper production in the same factory (mean 32.1 cfu/m(3)) and to corresponding stages of chip handling in the modern "B" factory (mean 94.4 cfu/m(3)) . The values of the respirable fraction of airborne Gram-negative flora were at most sites within a range of 40.0-56.9% . The species of the family Enterobacteriaceacae, mostly belonging to the genera Enterobacter, Pantoea, Rahnella and Klebsiella, distinctly prevailed in the air of the examined factories . Altogether, 19 species or genera of Gram-negative bacteria were identified in the collected air samples, out of these 9 were reported as having allergenic, immunotoxic and/or infectious properties . The concentration of dust in the air of paper factories ranged from 0.13-3.9 mg/m(3) and never exceeded the safe level . The concentration of bacterial endotoxin in the air of paper factories varied within a fairly wide range of 0.0042-2.5 micro g/m(3) . At 4 sites associated with initial chip handling and pulp production large concentrations of airborne endotoxin between 0.2-2.5 micro g/m(3) were found, significantly exceeding suggested safe levels . In conclusion, despite Gram-negative bacteria occur in the air of paper mills in relatively low concentrations which never exceeded the value of 1,000 cfu/m(3) proposed as safe level, they may exert adverse effects on exposed workers, as evidenced by high concentrations of airborne endotoxin and the presence of numerous potentially pathogenic species . Thus, these microorganisms pose a potential risk of respiratory disease for the workers of pulp and paper mills, in particular for those engaged in handling of wood chips and production of pulp.

J Econ Entomol, 2003 Jun, 96(3), 555 - 63
Suppression of leaf feeding and oviposition of phytophagous ladybird beetles (Coleoptera: Coccinellidae) by chitinase gene-transformed phylloplane bacteria and their specific bacteriophages entrapped in alginate gel beads; Otsu Y et al.; The chitinase gene-transformed strain KPM-007E/chi of Enterobacter cloacae was vitally entrapped in sodium alginate gel beads with its specific virulent bacteriophage EcP-01 to provide a new method for microbially digesting chitinous peritrophic membranes of phytophagous ladybird beetles Epilachna vigintioctopunctata . First, chitinase SH1 from a gram-positive bacterium Kurthia zopfii was overproduced by Escherichia coli cells and purified by affinity column chromatography . The purified enzyme effectively digested peritrophic membranes dissected from the ladybird beetles to expose epithelial tissues beneath the peritrophic membrane, and the beetles that had ingested chitinase after submergence in chitinase solution had considerably reduced their feeding on tomato leaves . KPM-007E/chi, entrapped in the alginate beads, released the chitinase . More chitinase was released when KPM-007E/chi was present with their specific virulent bacteriophage EcP-01 in the beads because of lysis of bacterial cells infected with the bacteriophages . This chitinase release from the microbial beads (containing KPM-007E/chi and EcP-01) was sufficient to digest the peritrophic membrane as well as to suppress feeding of bead-sprayed tomato leaves by the ladybird beetles . A daily supply of tomato leaves treated with the microbial beads considerably suppressed leaf feeding and oviposition by the ladybird beetles, suggesting a possible application of chitinase-secreting bacteria for suppressing herbivorous insect pests.

Clin Microbiol Infect, 2003 May, 9(5), 397 - 405
Anaerobic bacteria commonly colonize the lower airways of intubated ICU patients; Agvald-Ohman C et al.; OBJECTIVES: To investigate respiratory tract colonization by aerobic and anaerobic bacteria in mechanically ventilated patients . METHODS: Bacterial colonization of the stomach and the respiratory tract was qualitatively and quantitatively analyzed over time in 41 consecutive mechanically ventilated patients in a Swedish intensive care unit (ICU), with special emphasis on elucidation of the role of anaerobic bacteria in the lower respiratory tract . Samples were taken from the oropharynx, gastric juice, subglottic space and trachea within 24 h (median 14 h) of intubation, and then every third day until day 18 and every fifth day until day 33 . RESULTS: The patients were often heavily colonized with microorganisms not considered to belong to a healthy normal oropharyngeal and gastric flora on admission to the ICU . A majority harbored enterococci, coagulase-negative staphylococci and Candida spp . in at least one site on day 1 . Anaerobic bacteria, mainly peptostreptococci and Prevotella spp., were isolated from subglottic and/or tracheal secretions in 59% of the patients . Different routes of tracheal colonization for different groups of microorganisms were found . Primary or concomitant colonization of the oropharynx with staphylococci, enterococci, enterobacteria and Candida was often seen, while Pseudomonas spp., other non-fermenting Gram-negative rods and several anaerobic species often primarily colonized the trachea, indicating exogenous or direct gastrointestinal routes of colonization . CONCLUSIONS: Mechanically ventilated patients were heavily colonized in their lower airways by potential pathogenic microorganisms, including a high load of anaerobic bacteria . Different routes of colonization were shown for different species.

Infez Med, 1997, 5(1), 34 - 41
{Susceptibility of P . aeruginosa and enterobacteriaceae isolated from 1986 to 1994 in the Microbiology laboratory of the Infectious Diseases Institute of Perugia University}; Pasticci MB et al.; From 1986 to 1994, 812 P . aeruginosa, 1997 E . coli, 437 P . mirabilis, 400 Klebsiella spp., 238 Enterobacter spp., 130 Serratia spp . strains were isolated from clinical materials in the Microbiology laboratory of the Infectious Diseases Institute of Policlinico Monteluce, Perugia University . During the study period the Authors observed the following variations in the susceptibility patterns: increased resistance of P . aeruginosa to piperacillin from 20.8% to 27.2% (P<0.05), amikacin from 11.9% to 17.5% (P<0.05), netilmicin from 11.8% to 28.6% (P<0.01), pefloxacin from 74.4% to 87.8% (P<0.01); E . coli to norfloxacin, ciprofloxacin and pefloxacin, respectively from 1.3% to 3.6% (P<0.001), from 1.5% to 3.6% (P<0.05) and from 3.2% to 9% (P<0.001); Serratia spp . to ceftazidime from 14% to 33.3% (P<0.05); Enterobacter spp . to norfloxacin from 5.1% to 13.6% (P<0.05), cotrimoxazole from 12.8% to 23.5% (P<0.05) and chloramphenicol from 19.4% to 31.8% (P<0.05) . Moreover cephalotin resistant strains of E . coli decreased from 29.3% to 21.3% in the last 4 years (P<0.001).

J Clin Microbiol, 2003 Jul, 41(7), 3339 - 43
Comparison of four antimicrobial susceptibility testing methods to determine the in vitro activities of piperacillin and piperacillin-tazobactam against clinical isolates of Enterobacteriaceae and Pseudomonas aeruginosa; Karlowsky JA et al.; Susceptibility to piperacillin was similar to that to piperacillin-tazobactam (<1% difference) for 6,938 isolates of Enterobacter aerogenes and 13,954 isolates of Enterobacter cloacae tested using a Vitek system; for the same species, in contrast, susceptibility rates to piperacillin-tazobactam were 5.9 to 13.9% higher than to piperacillin using disk diffusion, MicroScan, and Vitek 2 testing . Unprecedented phenotypes (piperacillin susceptible and piperacillin-tazobactam intermediate; piperacillin intermediate and piperacillin-tazobactam resistant; piperacillin susceptible and piperacillin-tazobactam resistant) accounted for 6.1% of the results for E . aerogenes isolates and 6.0% of the results for E . cloacae isolates tested with the Vitek system.

J Clin Microbiol, 2003 Jul, 41(7), 2940 - 5
Molecular epidemiology and characterization of plasmid-encoded beta-lactamases produced by Tunisian clinical isolates of Salmonella enterica serotype Mbandaka resistant to broad-spectrum cephalosporins; Makanera A et al.; We studied 31 clinical isolates of Salmonella enterica serotype Mbandaka resistant to broad-spectrum cephalosporins and recovered in Tunisia over a 5-year period . The transferability of this resistance was demonstrated by conjugation experiments . Thirty of the 31 isolates were positive in the double-disk synergy test . By isoelectric focusing analysis, all of the isolates were found to produce a band of beta-lactamase activity with a pI of 5.9 . Three of these isolates produced an additional band with a pI of 7.6 . PCR and DNA sequencing identified these beta-lactamases as TEM-4 and SHV-2a, respectively . The remaining isolate, highly resistant to ceftazidime but susceptible to cefepime, produced a beta-lactamase that focused at pI 7.8 . No synergy was detected by the double-disk synergy test . Sequence analysis of the bla gene amplified by PCR showed that the plasmid-mediated AmpC-type enzyme was ACC-1a . Fingerprinting analysis by repetitive-element PCR and enterobacterial repeat intergenic consensus-PCR suggested that 29 of the 31 Salmonella serotype Mbandaka isolates belonged to the same clonal population.

Gac Sanit, 2003 May-Jun, 17(3), 204 - 9
{Waterborne outbreak of gastroenteritis transmitted through the public water supply}; Godoy P et al.; INTRODUCTION: The chlorination of public water supplies has led researchers to largely discard drinking water as a potential source of gastroenteritis outbreaks . The aim of this study was to investigate an outbreak of waterborne disease associated with drinking water from public supplies . METHODS: A historical cohort study was carried out following notification of a gastroenteritis outbreak in Baqueira (Valle de Aran, Spain) . We used systematic sampling to select 87 individuals staying at hotels and 67 staying in apartments in the target area.Information was gathered on four factors (consumption of water from the public water supply, sandwiches, water and food in the ski resorts) as well as on symptoms . We assessed residual chlorine in drinking water, analyzed samples of drinking water, and studied stool cultures from 4 patients . The risk associated with each water source and food type was assessed by means of relative risk (RR) and 95% confidence intervals (CI) . RESULTS: The overall attack rate was 51.0% (76/149) . The main symptoms were diarrhea 87.5%, abdominal pain 80.0%, nausea 50.7%, vomiting 30.3%, and fever 27.0% . The only factor associated with a statistically significant risk of disease was consumption of drinking water (RR = 11.0; 95% CI, 1.6-74.7) . No residual chlorine was detected in the drinking water, which was judged acceptable . A problem associated with the location of the chlorinator was observed and corrected . We also recommended an increase in chlorine levels, which was followed by a reduction in the number of cases . The results of stool cultures of the four patients were negative for enterobacteria . CONCLUSIONS: This study highlights the potential importance of waterborne outbreaks of gastroenteritis transmitted through drinking water considered acceptable and suggests the need to improve microbiological research into these outbreaks (viruses and protozoa detection).

Sci Prog, 2003, 86(Pt 1-2), 139 - 55
Extracellular proteins as enterobacterial thermometers; Rowbury RJ; Biological thermometers are cellular components or structures which sense increasing temperatures, interaction of the thermometer and the thermal stress bringing about the switching-on of inducible responses, with gradually enhanced levels of response induction following gradually increasing temperatures . In enterobacteria, for studies of such thermometers, generally induction of heat shock protein (HSP) synthesis has been examined, with experimental studies aiming to establish (often indirectly) how the temperature changes which initiate HSP synthesis are sensed; numerous other processes and responses show graded induction as temperature is increased, and how the temperature changes which induce these are sensed is also of interest . Several classes of intracellular component and structure have been proposed as enterobacterial thermometers, with the ribosome and the DnaK chaperone being the most favoured, although for many of the proposed intracellular thermometers, most of the evidence for their functioning in this way is indirect . In contrast to the above, the studies reviewed here firmly establish that for four distinct stress responses, which are switched-on gradually as temperature increases, temperature changes are sensed by extracellular components (extracellular sensing components, ESCs) i.e . there is firm and direct evidence for the occurrence of extracellular thermometers . All four thermometers described here are proteins, which appear to be distinct and different from each other, and on sensing thermal stress are activated by it to four distinct extracellular induction components (EICs), which interact with receptors on the surface of organisms to induce the appropriate responses . It is predicted that many other temperature-induced processes, including the synthesis of HSPs, will be switched-on following the activation of similar extracellular thermometers by thermal stimuli.

Ying Yong Sheng Tai Xue Bao, 2003 Mar, 14(3), 479 - 80
{Detection of heterotrophic bacteria and vibrios in shoal of Bullacta exarata}; Wang G et al.; The number of heterotrophic bacteria and vibrios in shoal for Bullacta exarata rearing fluctuated mainly within 1.25 x 10(4)-7.21 x 10(4) cfu.g-1 and 0-1.08 x 10(4) cfu.g-1, respectively . 173 strains of bacteria, mainly belong to 13 genera were isolated . The predominant genera were composed of Bacillus, Photobacterium, Pseudomonas, Vibrio and some genera of Enterobacteriaceae . The number of bacteria changed in line with the alteration of the temperature, and was especially affected by the organic matter content after the use of pesticide . The predominant genera such as Bacillus were closely related with the environmental deterioration of rearing shoal.

Drugs, 2003, 63(14), 1459 - 80
A practical guide to the treatment of complicated skin and soft tissue infections; Fung HB et al.; Complicated skin and soft tissue infections (SSTIs) remain a common reason for hospitalisation . Optimal management of complicated SSTIs begins with a physical examination, and obtaining the complete social and medical history of the patient . Empirical intravenous antibacterial therapy is guided by expected pathogens, patient factors and diagnostic procedure reports, such as the Gram-stained smear of discharge or exudates . The majority of community-acquired SSTIs are caused by Staphylococcus aureus and beta-haemolytic streptococci . On the basis of recent surveillance data, 80-90% of these pathogens remain susceptible to cefazolin or oxacillin . Consequently, a first generation cephalosporin or an antistaphylococcal penicillin remains the first line empirical therapy for community-acquired skin and soft tissue infections . Vancomycin may be an appropriate alternative when vancomycin-resistant S . aureus is highly suspected on the basis of patient history and co-morbid conditions . With the global emergence and spread of macrolide-resistant S . aureus and beta-haemolytic streptococci, clindamycin rather than a macrolide is the recommended agent for empirical antibacterial therapy of community-acquired SSTIs in penicillin-allergic patients . Nosocomial complicated SSTIs are predominantly caused by S . aureus, Pseudomonas aeruginosa, Enterococcus spp., Escherichia coli and other Enterobacteriaceae . Piperacillin/tazobactam with or without vancomycin is the preferred agent for empirical treatment depending on local resistance statistics . The newer fluoroquinolones may have a role in the treatment of complicated SSTIs, especially in penicillin-allergic patients . More clinical studies are needed before a formal recommendation can be made . Many of the newer antimicrobial agents such as the carbapenems, oxazolidinones and streptogramins have been shown to be effective for the treatment of complicated SSTIs . However, because of their proven activity against highly resistant organisms including methicillin-resistant S . aureus and vancomycin-resistant enterococci (oxazolidinones and streptogramins), and Gram-negative bacilli producing extended spectrum beta-lactamases (carbapenems), these antibacterials should be reserved for life-threatening situations and/or when resistant pathogens are suspected . Complicated skin and soft tissue infections are often associated with exudates, ulcerations, fluid collections or abscesses . Adequate debridement of devitalized tissues and drainage of abscesses and fluid collections in addition to systemic antibacterial therapy is an integral part of appropriate management.

FEMS Microbiol Lett, 2003 Jun 27, 223(2), 267 - 74
The beta-glucoside genes of Klebsiella aerogenes: conservation and divergence in relation to the cryptic bgl genes of Escherichia coli; Raghunand TR et al.; The ability to metabolize aromatic beta-glucosides such as salicin and arbutin varies among members of the Enterobacteriaceae . The ability of Escherichia coli to degrade salicin and arbutin appears to be cryptic, subject to activation of the bgl genes, whereas many members of the Klebsiella genus can metabolize these sugars . We have examined the genetic basis for beta-glucoside utilization in Klebsiella aerogenes . The Klebsiella equivalents of bglG, bglB and bglR have been cloned using the genome sequence database of Klebsiella pneumoniae . Nucleotide sequencing shows that the K . aerogenes bgl genes show substantial similarities to the E . coli counterparts . The K . aerogenes bgl genes in multiple copies can also complement E . coli mutants deficient in bglG encoding the antiterminator and bglB encoding the phospho-beta-glucosidase, suggesting that they are functional homologues . The regulatory region bglR of K . aerogenes shows a high degree of similarity of the sequences involved in BglG-mediated regulation . Interestingly, the regions corresponding to the negative elements present in the E . coli regulatory region show substantial divergence in K . aerogenes . The possible evolutionary implications of the results are discussed.

FEMS Microbiol Lett, 2003 Jun 27, 223(2), 147 - 51
Simple and reliable multiplex PCR assay for detection of blaTEM, bla(SHV) and blaOXA-1 genes in Enterobacteriaceae; Colom K et al.; Third-generation cephalosporin resistance is often mediated by TEM- and SHV-type beta-lactamases in Enterobacteriaceae . TEM-type and OXA-1 enzymes are the major plasmid-borne beta-lactamases implicated in amoxicillin-clavulanic acid resistance in Escherichia coli isolates . We have developed a rapid and simple multiplex polymerase chain reaction (PCR) which discriminates bla(TEM), bla(SHV) and bla(OXA-1) genes by generating fragments of 516, 392 and 619 bp respectively . Multiplex PCR analysis of 51 amoxicillin-clavulanate resistant E . coli isolates detected bla(TEM) and bla(SHV) genes in 45 and two strains, respectively, and only one strain harboured a bla(OXA-1) gene . Twenty-three of the 40 cefotaxime-resistant Enterobacteriaceae isolates produced amplicons with a size compatible with the presence of bla(TEM) (13 strains), bla(SHV) (six strains) genes or the association of both genes (four strains) . These results were verified by colony hybridisation . Therefore, multiplex PCR is a suitable tool for initial rapid screening of bla genes in Enterobacteriaceae.

Nucleic Acids Res, 2003 Jul 1, 31(13), 3527 - 32
EnteriX 2003: Visualization tools for genome alignments of Enterobacteriaceae; Florea L et al.; We describe EnteriX, a suite of three web-based visualization tools for graphically portraying alignment information from comparisons among several fixed and user-supplied sequences from related enterobacterial species, anchored on a reference genome . The first visualization, Enteric, displays stacked pairwise alignments between a reference genome and each of the related bacteria, represented schematically as PIPs (Percent Identity Plots) . Encoded in the views are large-scale genomic rearrangement events and functional landmarks . The second visualization, Menteric, computes and displays 1 Kb views of nucleotide-level multiple alignments of the sequences, together with annotations of genes, regulatory sites and conserved regions . The third, a Java-based tool named Maj, displays alignment information in two formats, corresponding roughly to the Enteric and Menteric views, and adds zoom-in capabilities . The uses of such tools are diverse, from examining the multiple sequence alignment to infer conserved sites with potential regulatory roles, to scrutinizing the commonalities and differences between the genomes for pathogenicity or phylogenetic studies . The EnteriX suite currently includes >15 enterobacterial genomes, generates views centered on four different anchor genomes and provides support for including user sequences in the alignments.

Antimicrob Agents Chemother, 2003 Jul, 47(7), 2330 - 3
Sfh-I, a subclass B2 metallo-beta-lactamase from a Serratia fonticola environmental isolate; Saavedra MJ et al.; An environmental isolate of Serratia fonticola resistant to carbapenems was shown to contain a genetic determinant encoding a metallo-beta-lactamase of the subclass B2 . The Sfh-I enzyme exhibits some divergence from the previously characterized enzymes of this subclass . This is the first example of a naturally occurring metallo-beta-lactamase in Enterobacteriaceae.

Antimicrob Agents Chemother, 2003 Jul, 47(7), 2179 - 85
Survey of plasmid-associated genetic markers in enterobacteriaceae with reduced susceptibilities to cephalosporins; Preston KE et al.; Clinical isolates of Enterobacteriaceae with reduced susceptibilities to cephalosporins were collected from 1993 to 2000 . The organisms were screened for the extended-spectrum beta-lactamase (ESBL) phenotype, and plasmid extracts were screened for genetic markers by hybridization . A bla(TEM) probe was derived from pUC19; other probes were derived from pACM1, the plasmid responsible for the first known appearance of an ESBL in our institution . These probes included bla(SHV), int, aac(3)-Ia, dfrA1, IS6100, tetA, IncM markers, and Anon 13, a marker for the Klebsiella pneumoniae chromosomal sequences that flank bla(SHV-5) . There were 42 hybridization patterns among 237 isolates . Patterns designated pACM1-like occurred in 44% of the isolates (eight species) and were always associated with the clavulanic acid (CA)-susceptible ESBL phenotype . The TEM marker was not predictive of the ESBL phenotype . Mapping indicated the presence of an SHV marker and up to 7.5 kb of its flanking chromosomal sequences in three non-IncM plasmids obtained in transformation experiments . We theorize that this DNA segment spread to other plasmids from pACM1-like sources . CA insensitivity became more frequent with time and was usually associated with either the TEM marker or the absence of both bla markers . One plasmid-encoded enzyme with characteristics of an AmpC beta-lactamase was observed in a transformant lacking both TEM and SHV markers . Although SHV type ESBLs were a continuing source of reduced susceptibility to cephalosporins in our institution, organisms with different resistance mechanisms were added to the hospital microflora in later years . These changes might be related, in part, to ESBL control strategies implemented in 1995.

Infect Immun, 2003 Jul, 71(7), 3937 - 46
The C-terminal domain of Salmonella enterica serovar typhimurium OmpA is an immunodominant antigen in mice but appears to be only partially exposed on the bacterial cell surface; Singh SP et al.; We examined the way the major outer membrane protein OmpA of Salmonella enterica serovar Typhimurium is recognized by the mouse immune system, by raising a panel of 12 monoclonal antibodies (MAbs) against this protein . Interaction between OmpA and these MAbs is competitively inhibited with several-hundredfold dilutions of mouse polyclonal sera obtained by immunization with live or heat-killed whole cells, suggesting that OmpA is one of the immunodominant antigens of serovar Typhimurium . All of the MAbs were specific for an identical epitope(s) located on the C-terminal domain of OmpA, as indicated by the use of OmpA fragments generated by protease or cyanogen bromide treatment and by competitive inhibition enzyme-linked immunosorbent assay . This epitope was highly conserved within (but not outside) the family Enterobacteriaceae: The strong immunogenicity of this epitope was surprising because the C-terminal domain of OmpA, usually thought to be located in the periplasm, is not expected to be exposed on the bacterial cell surface . A MAb, however, reacted in a cytofluorometry assay more strongly with outer-membrane-permeabilized cells than with untreated cells, a result supporting the predominantly periplasmic localization of the epitope . Significant, though low-level, reactivity of intact cells nevertheless suggests that in some cells the C-terminal domain of OmpA is exposed on the surface, a result consistent with the proposal that OmpA can fold into one of the two alternate conformations.

Diagn Microbiol Infect Dis, 2003 Jun, 46(2), 125 - 30
Evaluation of MicroScan ESBL confirmation panel for Enterobacteriaceae-producing, extended-spectrum beta-lactamases isolated in Japan; Komatsu M et al.; We assessed use of the MicroScan ESBL confirmation panel (Dade Behring, Tokyo, Japan) for the detection of eight Enterobacteriaceae-producing extended-spectrum beta-lactamases (ESBL) species . Of 137 bacterial strains isolated from patients in 32 hospitals in the Kinki area of Japan, 91 produced ESBL and comprised 60 bacteria (of E . coli, K . oxytoca, and K . pneumoniae) targeted by the NCCLS ESBL test and 31 non-target bacteria such as chromosomal AmpC-producing bacteria (e.g., Serratia marcescens, Enterobacter spp.) . Sensitivity and specificity of the MicroScan panel for the target bacteria were 92% and 93%, respectively; sensitivity and specificity for non-target bacteria were 52% and 100%, respectively . There were 20 ESBL-positive strains that were not inhibited by clavulanic acid in the MicroScan panel (3 of 32 ESBL-producing E . coli strains, 1 of 24 K . pneumoniae, 1 of 4 K . oxytoca, 8 of 13 E . cloacae, and 7 of 14 S . marcescens), and most of them were bacteria not targeted by the NCCLS test . In 19 of the 20 strains, the synergy effect of clavulanic acid was observed in the modified-double-disk synergy test using only the cefepime-disk . Because these strains had high MICs of > or = 16 microg/ml for cephamycins such as cefoxitin and cefmetazole, these strains might produce high levels of AmpC in addition to ESBL . The MicroScan ESBL confirmation panel showed excellent performance in detecting target, but not other bacteria . Addition of cefepime and clavulanic acid to the MicroScan panel may significantly improve detection of non-target bacteria.

Zhonghua Shao Shang Za Zhi, 2003 Apr, 19(2), 71 - 4
{Clinical significance of the predominant bacterial strains on burn wound during early postburn stage}; Li TZ et al.; OBJECTIVE: To investigate the clinical significance of the predominant bacterial colonization on burn wound in our department during recent years, so as to help select optimal antibiotics in burn patients with severe infections . METHODS: This bacterial investigation was carried out in 215 cases of severely burned patients . The bacterial culture and the drug susceptibility test were carried out . RESULTS: (1) One hundred and twenty-two strains of bacteria were cultured, in which 28 strains (23%) were Staphylococcus with negative coagulase, 27 (22%) S . aureus, 17 (14%) Pseudomonas aeruginosa, 11 (9%) Escherichia coli, 10 (8%) Enterobacter, 9 (7%), enterococci, 3 (2.5%) fungi, and 17 (14.5) other bacteria . (2) The resistance of S . aureus to ampicillin, oxacillin and amoxicillin/clavulanic acid was 81%, 38% and 31%, respectively . 11% and 16% of Pseudomonas aeruginosa resistant to Imipenem and Ceftazidime, respectively . (3) The sensitivity of G + cocci to vancomycin and norvancomycin, Chloramphenicol, Teicoplanin, Trimethoprim/Sulfamethoxaz, Rifampin was 100%, 100%, 100%, 94% and 88% respectively, and the Gram-negative bacilli to Meropenem, Imipenem, Amikacin, Cefepime, Cefoperazone/Sulbactam, Ceftazidime were 91%, 90%, 81%, 78%, 71% and 70%, respectively . Furthermore, the sensitivity of Pseudomonas aeruginosa to Cefoperazone/Sulbactam, Ceftazidime, Tobramycin, Meropenem, Amikacin, Ciprofloxacin, Amikacin, Cefepime were between 82% and 91% . MRSA was very sensitive to both vancomycin and norvancomycin . CONCLUSION: The results suggested that Staphylococcus with negative coagulase and S . aureus were the predominant bacteria and Pseudomonas aeruginosa ranked second . The resistance of these bacteria to antibiotics was on the increase . Moreover, colonization of enterococcus and fungi on burn wound increased recently, which were scarce before . This implied the importance of rational and correct use of antibiotics during early postburn stage.

J Appl Microbiol, 2003, 95(1), 180 - 5
Occurrence and antimicrobial resistance of Gram-negative bacteria isolated in haemodialysis water and dialysate of renal units: results of a Greek multicentre study; Arvanitidou M et al.; AIMS: To evaluate the occurrence, identity and antimicrobial resistance of Gram-negative bacteria isolated from municipal water supplies, treated water, and dialysate of all 85 Greek haemodialysis centres . METHODS AND RESULTS: A total of 141 Gram-negative bacterial isolates (98 non-fermentative and 43 enterobacteria) were recovered from 255 water samples . Twenty-four of them were isolated from tap water, 31 from treated water, and 86 from dialysate samples . The mean concentrations (CFU per 100 ml +/- s.d.) of the positive Gram-negative bacteria samples were 69.2 +/- 43.9, 31.2 +/- 28.7 and 3552.3 +/- 4485.0, respectively . The most common isolates, in order of frequency were Pseudomonas aeruginosa (22.7%), Chryseobacterium meningosepticum (14.9%), Stenotrophomonas maltophilia (13.5%), Escherichia coli (12.8%) and Enterobacter cloacae (7.8%), representing 71.6% of all isolates . Ps . aeruginosa was the most prevalent isolate in all types of water sample followed by C . meningosepticum in tap and treated water and by E . coli in dialysate . Nineteen per cent of the enterobacteria and 35% of the non-fermenters were resistant against three or more of the nine antibiotics tested . CONCLUSIONS: These data suggest that dialysate and treated water could be a source of infection for several non-fermentative and enterobacterial species . IMPACT OF THE STUDY: Microbiological monitoring of such samples is needed in order to know the identity and antibiotic resistance profiles of their potentially pathogenic bacterial population.

Commun Dis Intell, 2003, 27 Suppl, S47 - 54
Fifteen years of surveillance by the Australian Group for Antimicrobial Resistance (AGAR); Nimmo GR et al.; The Australian Group for Antimicrobial Resistance (AGAR) has played a unique role in surveillance of antimicrobial resistance in Australia . It has a broad laboratory membership representing the major teaching hospitals in all Australian capitals and more recently major private pathology laboratories in most states . The use of an active surveillance strategy with standard methodology for collection and examination of clinically significant isolates has produced data accurately reflecting the changing prevalence of antimicrobial resistance in major hospitals as well as the community . AGAR has documented the spread of methicillin-resistant Staphylococcus aureus in Australian hospitals in the late 1980s and throughout the 1990s . Surveys of antimicrobial resistance in enterococci have monitored the emergence of vancomycin-resistant enterococci as an important nosocomial pathogen in Australia . AGAR has also conducted major national surveys of resistance in Streptococcus pneumoniae, community isolates of Staphylococcus aureus, Haemophilus influenzae and in the Enterobacteriaceae . These and other activities have given AGAR a unique perspective on emerging patterns of resistance in key pathogens in Australia . The recent extension of membership to include more private pathology laboratories may provide the opportunity to conduct more representative community based surveys.

Int J Syst Evol Microbiol, 2003 May, 53(Pt 3), 807 - 10
Escherichia albertii sp . nov., a diarrhoeagenic species isolated from stool specimens of Bangladeshi children; Huys G et al.; The taxonomic position of a group of five D-sorbitol- and lactose-negative enterobacterial isolates recovered from diarrhoeal stools of children at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), was investigated by DNA-DNA hybridization, phenotypic characterization and 16S rDNA sequencing . These strains were originally identified as 'Hafnia alvei-like' with the API 20E system but, in fact, show more phenotypic and genotypic resemblance to members of the genus Escherichia . By 16S rDNA sequencing, one representative strain of the ICDDR,B group was shown to be closely affiliated to the genera Escherichia and Shigella . Using the fluorimetric microplate hybridization method, the diarrhoeagenic ICDDR,B isolates were found to constitute a homogeneous taxon (> or = 82% internal DNA relatedness), with the closest affiliation to the type strains of Escherichia coli (55-64%) and Shigella flexneri (54-60%) . The DNA-DNA hybridization levels were much lower with members of other described Escherichia species (16-45%) and with the type strain of H . alvei (9-17%) . The G + C content of the ICDDR,B strains ranged from 50.5 to 50.7 mol% . Together with the diagnostic characteristics reported previously, including the presence of the eaeA gene of enteropathogenic E . coli and of the E . coli and Shigella-specific phoE gene, it is concluded that the ICDDR,B strains represent a novel taxon in the genus Escherichia, for which the name Escherichia albertii sp . nov . is proposed . Its type strain is Albert 19982(T) (= LMG 20976(T) = CCUG 46494(T)).

Int J Syst Evol Microbiol, 2003 May, 53(Pt 3), 661 - 8
Recognition of two genetic groups in the Klebsiella oxytoca taxon on the basis of chromosomal beta-lactamase and housekeeping gene sequences as well as ERIC-1 R PCR typing; Granier SA et al.; Whilst searching for a molecular method to identify the different species of Raoultella and Klebsiella oxytoca, it was observed that the OXY-1 and OXY-2 beta-lactamase-producing K . oxytoca isolates displayed two distinguishable enterobacterial repetitive intergenic consensus (ERIC)-1R profiles . It was hypothesized that the two groups of chromosomal beta-lactamases might correspond to two groups of strains in the K . oxytoca taxon . To confirm this hypothesis, clinical isolates and reference strains of K . oxytoca were studied by determination of the sequence of their bla(OXY) genes, and of a partial fragment of their 16S rRNA (387 bp) and rpoB (512 bp) genes . The sequence data were phylogenetically analysed by using the parsimony method . Four clinical isolates possessed a bla(OXY-1) gene and nine possessed a bla(OXY-2) gene . The mean percentage of rpoB and 16S rRNA gene identity was > 99% within each group of strains, whereas it was 96.56 +/- 0.24% for rpoB genes and 97.80 +/- 0.22% for 16S rRNA genes between the group of strains harbouring the bla(OXY-1) gene and the group harbouring the bla(OXY-2) gene . The phylogenetic tree resulting from combined analysis of the 16S rRNA and rpoB datasets showed that the K . oxytoca isolates were monophyletic and separated into two clades; these clades included strains with either the bla(OXY-1) gene or the bla(OXY-2) gene . This result was supported with high bootstrap values of 97 and 99%, respectively . Moreover, the two groups of strains displayed distinct ERIC-1R profiles, with bands characteristic of each profile . Thus, the chromosomal bla(OXY) gene sequence is able to delineate not only two groups of beta-lactamases in K . oxytoca, but also two clades in the K . oxytoca taxon, in a manner similar to the sequence of housekeeping genes . These results suggest that K . oxytoca should be divided into two genetic groups, group OXY-1 represented by K . oxytoca strain SL781 (=CIP 104963) and group OXY-2 by K . oxytoca strain SL91l (= CIP 106098).

Am J Infect Control, 2003 Jun, 31(4), 208 - 14
Persistent silver disinfectant for the environmental control of pathogenic bacteria; Brady MJ et al.; BACKGROUND: Contaminated surfaces can act as a reservoir for pathogenic microorganisms and potentially exacerbate the risk of infection . Surface disinfection and decontamination provide temporary amelioration against bacterial colonization . Disinfected surfaces eventually become contaminated, thus, mitigating the benefit of the initial disinfection . It is hypothesized that to improve on the current state of the art, a disinfectant should not only immediately disinfect a surface but also provide persistent antimicrobial action after the product has been applied . We describe here a silver-based disinfectant technology designed to provide long-lasting sanitization and disinfection to treated surfaces as evaluated on hard surfaces after repeated environmental insults . METHODS: A comparative evaluation of 6 disinfectant formulations for residual antimicrobial activity after water rinsing was performed . Log reduction of bacterial populations on disinfectant-treated substrates were measured after 30 minutes to 8 hours of exposure and compared with an untreated control . In a similar study, the residual antimicrobial activity of a silver disinfectant was evaluated against antibiotic- and biocide-resistant bacteria also after water rinsing . Further, residual antimicrobial activity of the silver disinfectant was measured after 5 cycles of rinsing, abrasion, and contamination against representative household and nosocomial pathogens (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter aerogenes, Enterococcus faecium, or Salmonella choleraesuis) after 10-minute exposure times . RESULTS: In the comparative assay, only the silver disinfectant and a persistent quaternary ammonium compound disinfectant demonstrated significant residual activity (> or =3.0 log(10) reduction to control) against S aureus whereas only the silver disinfectant demonstrated activity against Pseudomonas . No residual activity (< or = 0.5 log reduction to untreated control) was observed for the other disinfectant products . The silver-based disinfectant also showed significant and equivalent efficacy against antibiotic- and silver-resistant bacteria . In addition, the silver disinfectant was able to achieve significant residual activity in 10 minutes against all organisms tested after 1, 3, and 5 cycles of water rinse, abrasion, and microbial contamination . CONCLUSIONS: The findings show the ability of a new silver-based disinfectant to reduce bacterial populations that contact treated surfaces within minutes, highlight the potential to interrupt cross-contamination from environmental surfaces, and reduce the risk of infection within the home and health care settings.

J Endotoxin Res, 2003, 9(2), 67 - 84
Towards antibacterial strategies: studies on the mechanisms of interaction between antibacterial peptides and model membranes; Wiese A et al.; Lipopolysaccharides (LPSs) play a dual role as inflammation-inducing and as membrane-forming molecules . The former role attracts significantly more attention from scientists, possibly because it is more closely related to sepsis and septic shock . This review aims to focus the reader's attention to the other role, the function of LPS as the major constituent of the outer layer of the outer membrane of Gram-negative bacteria, in particular those of enterobacterial strains . In this function, LPS is a necessary component of the cell envelope and guarantees survival of the bacterial organism . At the same time, it represents the first target for attacking molecules which may either be synthesized by the host's innate or adaptive immune system or administered to the human body . The interaction of these molecules with the outer membrane may not only directly cause the death of the bacterial organism, but may also lead to the release of LPS into the circulation . Here, we review membrane model systems and their application for the study of molecular mechanisms of interaction of peptides such as those of the human complement system, the bactericidal/permeability-increasing protein (BPI), cationic antibacterial peptide 18 kDa (CAP18) as an example of cathelicidins, defensins, and polymyxin B (PMB) . Emphasis is on electrical measurements with a reconstitution system of the lipid matrix of the outer membrane which was established in the authors' laboratory as a planar asymmetric bilayer with one leaflet being composed solely of LPS and the other of the natural phospholipid mixture . The main conclusion, which can be drawn from these investigations, is that LPS and in general its negative charges are the dominant determinants for specific peptide-membrane interactions . However, the detailed mechanisms of interaction, which finally lead to bacterial killing, may involve further steps and differ for different antibacterial peptides.

Bull Exp Biol Med, 2003 Feb, 135(2), 178 - 80
Tissue hypoxia and intestinal dysbiosis in children with tuberculosis; Stenina MA et al.; We studied the role of autochthonous microflora from body cavities in the development of tissue hypoxia and instability of cell membranes . In children with tuberculosis dysbiosis manifested in nonspecific quantitative changes in the intestinal microflora and the presence of coxsackievirus antigens in the urine . DNA-containing viruses with pronounced immunosuppressive activity (e.g., herpesvirus, measles virus, and rubella virus) were found in most children . Microbiological and virological changes were accompanied by the appearance of laboratory signs for tissue hypoxia, which included inhibition of Krebs cycle dehydrogenases and alpha-glycerophosphate pathway in blood lymphocytes . Regression analysis revealed a relationship between the content of extraintestinal coxsackieviruses and inactivation of alpha-glycerophosphate dehydrogenase, succinate dehydrogenase and ratio of facultatively anaerobic bacteria in microbiocenosis, and expression of acid phosphatase and total population of malonate-positive enterobacteria, staphylococci, yeasts, and enterococci.

Res Vet Sci, 2003 Aug, 75(1), 9 - 14
Effects of probiotics: alone and in a mixture of Biosacc plus Zinc Bacitracin on the caecal microflora of Japanese quail; Siriken B et al.; The aim of this study was to investigate the effects of two commercially available probiotics, alone and in combination with an antibiotic, on the caecal flora of Japanese quail (Coturnix coturnix japonica) reared under unstressed conditions . Thirty-four 90-day-old Japanese quail were selected for this study . The birds were divided into four groups, two groups of nine birds and two groups of eight birds . The animals in these groups were given feed containing 0.5 kg per tonne of probiotics alone (Protexin or Biosacc), a mixture of probiotic plus antibiotic (Biosacc plus Zinc Bacitracin at 0.5 and 0.0525 ppm, respectively), and a group where no supplement was added to be used as controls . The total count of aerobic bacteria, lactobacilli, enterobacteriaceae, coliforms, enteroccoci, salmonellae, sulphite-reducing anaerobic bacteria (clostridia), and pH values in the caecal content of the birds were examined . No significant differences were detected among the four groups for pH values and bacterial number (p>0.05), except for sulphite-reducing anaerobic bacteria (p<0.001) . These results suggest that the use of probiotics alone and/or a mixture of a probiotic plus antibiotic as a feed supplement does not have a major suppressing effect on the majority of bacterial groups in the caecal flora of mature, healthy Japanese quail reared in unstressed conditions.

J Food Prot, 2003 Jun, 66(6), 946 - 52
Microbiological monitoring of sheep carcass contamination in three Swiss abattoirs; Zweifel C et al.; At three Swiss abattoirs, 580 sheep carcasses were examined at 10 sites by the wet-dry double-swab technique . The aim of this study was to obtain data on microbiological contamination at the abattoirs and to develop a procedure for monitoring slaughter hygiene . Median aerobic plate counts (APCs) (log CFU/cm2) ranged from 2.5 to 3.8, with the brisket and neck sites showing the most extensive contamination . Enterobacteriaceae were detected on 68.1% of the carcasses and in 15.2% of the samples . The proportion of positive results ranged from 2.6% (for the hind leg and the flank at abattoir C) to 42.2% (for the perineal area at abattoir A) . The percentage of samples testing positive for stx genes by polymerase chain reaction was 36.6% . A significant relationship between APC and the detection of Shiga toxin-producing Escherichia coli (STEC) was found for abattoirs A and B (depending on sampling site), whereas a significant relationship between Enterobacteriaceae and STEC detection was confirmed only for abattoir A (P < 0.05) . In 57.1% of the 56 isolated non-O157 strains, stx2 genes were detected, and most of them were stx2d positive . Additional virulence factors were detected in 50% of the STEC strains, with 8.9% of these strains being eae positive, 50% being EHEC-hlyA positive, and 3.6% being astA positive . For the determination of carcass contamination, the monthly examination of 10 sheep carcasses for APC and Enterobacteriaceae counts in the neck, brisket, and perineal areas is recommended . This procedure is a valuable tool for the verification of slaughter hygiene according to hazard analysis critical control point principles.

J Chemother, 2003 Apr, 15(2), 139 - 42
Ceftriaxone (1 g intravenously) penetration into abdominal tissues when administered as antibiotic prophylaxis during nephrectomy; Leone M et al.; A pharmacokinetics study was conducted to determine the effects of ceftriaxone administered before nephrectomy on the occurrence of postoperative wound infection . Ceftriaxone was administered as antibiotic prophylaxis in 11 consecutive patients undergoing nephrectomy who received 1,000 mg intravenously 30 min before surgery . Simultaneous blood and tissue samples were collected at three stages of the surgical procedure: opening of the abdominal cavity, nephrectomy, and closure of the abdominal cavity . Samples of following tissues were assayed: abdominal-wall fat, perirenal fat, kidney cortex and medulla, and urine . During the different stages of surgical procedures, ceftriaxone concentrations remained higher than the MIC90 of the potential pathogens (Staphylococcus aureus, Escherichia coli, and Enterobacteriaceae) . In selected patients undergoing nephrectomy and requiring antimicrobial prophylaxis such as malnourished, debilitated, diabetic or immunosuppressed patients, the use of a single dose of ceftriaxone (1,000 mg) makes it possible to offer an optimal bacterial coverage for the prevention of postoperative infection . According to our kinetic evaluation, ceftriaxone is potentially a good antibiotic for prophylaxis in urological surgery.

Zhong Yao Cai, 2003 Feb, 26(2), 106 - 9
{The inhibitory effect of extracts from Galla chinensis on marine fouling bacteria}; Li C et al.; OBJECTIVE: To observe the activity of extracts from Galla Chinensis with different solvents against marine fouling bacteria in vitro . METHOD: Incubating plate with foveolae was used . RESULTS: The ethyl acetate, ethanol and water extracts showed strong inhibitory activity against marine fouling bacteria belonging to nine genera including Pseudomonas, Aeromonas, Alealigenes, Flavobacterium, Vibrio, Photobacterium, Moraxella, Chromobacterium, Enterobacter . While, the petroleum ether and chloroform extracts showed no inhibitory activity . CONCLUSION: The study provided theory basis for new biologic protective dope on environment.

J Clin Microbiol, 2003 Jun, 41(6), 2477 - 82
Dissemination of SHV-12 and characterization of new AmpC-type beta-lactamase genes among clinical isolates of enterobacter species in Korea; Lee SH et al.; To determine the prevalence and genotype of an extended-spectrum beta-lactamase and new chromosomal AmpC beta-lactamases among clinical isolates of Enterobacter species, we performed antibiotic susceptibility testing, pI determination, induction tests, transconjugation, enterobacterial repetitive consensus (ERIC) PCR, sequencing, and phylogenetic analysis . Among the 51 clinical isolates collected from a university hospital in Korea, 6 isolates have been shown to produce SHV-12 and inducible AmpC beta-lactamases . These also included three isolates producing TEM-1b and one strain carrying TEM-1b and CMY-type beta-lactamases with a pI of 8.0 . The results from ERIC PCR revealed that six isolates were genetically unrelated, suggesting that dissemination of SHV-12 was responsible for the spread of resistance to extended-spectrum beta-lactams in Korea . Six genes of inducible AmpC beta-lactamases that are responsible for the resistance to cephamycins (cefoxitin and cefotetan), amoxicillin, cephalothin, and amoxicillin-clavulanic acid were cloned and characterized . A 1,165-bp DNA fragment containing the ampC genes was sequenced and found to have an open reading frame coding for a 381-amino-acid beta-lactamase . The nucleotide sequence of four ampC genes (bla(EcloK992004.1), bla(EcloK995120.1), bla(EcloK99230), and bla(EareK9911729)) shared considerable homology with that of AmpC-type class C beta-lactamase genes of gram-negative bacteria, especially that of the chromosomal ampC gene (bla(EcloMHN1)) of Enterobacter cloacae MHN1 (99.9, 99.7, 99.6, and 99.6% identity, respectively) . The sequences of two ampC genes (bla(EcloK9973) and bla(EcloK9914325)) showed close similarity to the chromosomal ampC gene (bla(EcloQ908R)) of E . cloacae Q908R (99.7% identity) . The results from phylogenetic analysis suggested that six ampC genes could originate from bla(EcloMHN1) or bla(EcloQ908R).

Vet Rec, 2003 May 17, 152(20), 615 - 7
Use of clinical information to predict the characteristics of bacteria isolated from clinical cases of bovine mastitis; Milne MH et al.; Farmers recorded the clinical signs of cows with clinical mastitis and submitted milk samples for bacteriological examination, so that the clinical signs could be correlated with the bacteriological findings . Odds ratios for the demeanour of the cow, the appearance of the milk, milk yield, udder texture, and the administration of parenteral antibiotics were calculated for mastitis cases classified in terms of their microbiology as either enterobacteriaceae, major Gram-positive pathogens, minor pathogens, 'no growths' or 'all other pathogens' . Animals infected with enterobacteriaceae had the highest odds of being reported as having a reduced milk yield, swollen or hard udders, watery milk and/or being systemically sick . A logistic regression model was used to predict the Gram-staining characteristics of the bacteria causing clinical mastitis . The clinical findings found to be significant predictors in the model were the demeanour of the cow and its milk yield . The regression model was used as a basis for a predictive test . Using a test data set, the sensitivity of the test was 28 per cent, its specificity was 96 per cent, the positive predictive value was 74 per cent and the negative predictive value was 80 per cent . The overall accuracy of these predictions was 79 per cent.

Neurogastroenterol Motil, 2003 Jun, 15(3), 267 - 76
Interdigestive small bowel motility and duodenal bacterial overgrowth in experimental acute pancreatitis; Van Felius ID et al.; The objective of this study is to investigate the effects of an acute necrotizing pancreatitis (ANP), without biliary obstruction, on the migrating motor complex (MMC), small bowel bacterial overgrowth (SBBO), bacterial translocation (BT) and infection of the pancreas simultaneously . Rats were divided into four groups: mild pancreatitis, control, ANP and sham operated control . Jejunal myoelectrodes were used to measure MMCs . Blood, peritoneal fluid, bile, and abdominal organs were harvested for microbial culturing 72 h after induction of pancreatitis . The splenic portion of the pancreas was taken for histology . During ANP the MMC cycle length was significantly increased from 14.1 +/- 0.2 to 22.4 +/- 1.9 min (P < 0.05) . The duodenum of ANP rats was in contrast with the other groups characterized by Enterobacteriacae (> 3 log 10 CFU g-1 in seven of 12 rats, P < 0.05) . A positive correlation (r = 0.78, P < 0.01) existed between duodenal Gram-negative and anaerobic flora and the MMC cycle . Correlation between MMC cycle length and BT to the pancreas was positive as well (r = 0.70, P < 0.01) . A positive correlation (r = 0.85, P < 0.01) was found between the severity of pancreatitis and duodenal bacterial overgrowth . During ANP without biliary obstruction, the jejunal MMC is disturbed and consequently SBBO occurs . The correlation between the severity of pancreatitis, the disturbance of the MMC and SBBO suggests an important pathophysiological role of the proximal small bowel in the infection of pancreatic necrosis.

J Am Vet Med Assoc, 2003 Jun 1, 222(11), 1582 - 9
Antimicrobial resistance of bacteria isolated from dairy cow milk samples submitted for bacterial culture: 8,905 samples (1994-2001); Makovec JA et al.; OBJECTIVE: To determine whether antimicrobial resistance patterns of major mastitis pathogens isolated from milk samples from dairy cows have changed over time . DESIGN: Retrospective study . SAMPLE POPULATION: 8905 bacterial isolates obtained from milk samples submitted to the Wisconsin Veterinary Diagnostic Laboratory between January 1994 and June 2001 . PROCEDURE: Antimicrobial susceptibility was determined by means of the Kirby-Bauer disk diffusion method . Logistic regression was used to determine whether percentages of isolates resistant to various antimicrobials changed over time . RESULTS: For the gram-positive mastitis pathogens, percentages of isolates resistant to various flactam antimicrobials did not increase over the course of the study . Percentage of Staphylococcus aureus isolates resistant to penicillin decreased from 49 to 30%; percentage of Streptococcus isolates resistant to penicillin decreased from 6 to 1% . Percentage of isolates resistant to erythromycin increased for S aureus, Escherichia coli, Enterobacter spp, Enterococcus spp, and Pasteurella spp . Percentage of isolates resistant to lincomycin increased for S aureus and Staphylococcus spp . Percentage of coagulase-negative Staphylococcus isolates resistant to pirlimycin increased from 6 to 19% . For several pathogens, percentages of isolates resistant to sulfisoxazole and to trimethoprim-sulfamethoxazole decreased . No pathogens had a significant increase in the percentage of isolates resistant to novobiocin-penicillin . CONCLUSIONS AND CLINICAL RELEVANCE: Results did not indicate a trend toward increased antimicrobial resistance among mastitis pathogens isolated from milk samples from dairy cows between 1994 and 2001 . Reduced resistance to flactam antimicrobials was identified for several gram-positive mastitis pathogens.

Int J Food Microbiol, 2003 Jul 25, 84(2), 145 - 56
Influence of food preservation parameters and associated microbiota on production rate, profile and stability of acylated homoserine lactones from food-derived Enterobacteriaceae; Ravn Flodgaard L et al.; Quorum-dependent regulation is mediated by N-acyl-L-homoserine lactones (AHLs) in several Gram-negative bacteria . The production of AHLs has typically been studied using pure bacteria cultures grown in nutrient-rich media at optimal temperature . AHLs are produced in several chill-stored foods by Gram-negative bacteria participating in spoilage . As part of our investigation of the role of AHLs in food quality, we studied the AHL production in two Enterobacteriaceae isolated from cold-smoked salmon under growth conditions typical of those found in cold-smoked salmon . We tested the influence of carbon source (glucose, sucrose, xylose, arabinose, mannose, mannitol and sorbitol), temperature (5 and 25 degrees C), salt concentration (0-7%), pH (6, 7 and 8) and co-existing lactic acid bacteria microflora on the AHL profile and production rate from Serratia proteamaculans strain B5a and Enterobacter agglomerans strain B6a . The two strains produced the same types of AHLs under all conditions tested . The specific AHL concentrations (moles/liter/OD(450)) changed slightly for both strains at the various conditions . S . proteamaculans strain B5a produced approximately 150 nM/OD(450) N-3-oxo-hexanoyl homoserine lactone (OHHL) and E . agglomerans strain B6a produced two major signals, OHHL and N-3-oxo-octanoyl homoserine lactone (OOHL) in a 1:9 ratio with a total concentration of approximately 3000 nM/OD(450) . The AHL signal molecules became unstable with increasing pH (>7.5) . In cold-smoked salmon, pH is approximately 6 and therefore only a low degree of pH-induced turnover is expected to occur in this product . Overall, our study demonstrates that food-derived Enterobacteriaceae produce AHLs of the same type and in the same magnitude when grown under food-relevant conditions as when grown in laboratory media at high temperature . Also, the AHLs produced in foods will be relatively stable and their regulatory impact lasting during storage.

Int Immunopharmacol, 2003 Jun, 3(6), 853 - 64
Bartonella quintana lipopolysaccharide effects on leukocytes, CXC chemokines and apoptosis: a study on the human whole blood and a rat model; Matera G et al.; Bartonella quintana, an emerging gram-negative pathogen, may cause trench fever, endocarditis, cerebral abscess and bacillary angiomatosis usually with the absence of septic shock in humans . B . quintana lipopolysaccharide (LPS), a deep rough endotoxin with strong reactivity in the limulus amebocyte lysate (LAL)-assay, was studied in human whole blood and in a rat model . A significant (P<0.05) increase of interleukin-8 (IL-8) concentration, comparable to the level induced by enterobacterial LPS, was stimulated in the human whole blood by B . quintana LPS . Isolated human neutrophils delayed their apoptotic behavior in the presence of B . quintana LPS . In the rat, B . quintana LPS induced a significant (P<0.001) increase in white blood cell count, both 30 and 60 min after intravenous injection . Such leukocytosis was inhibited by pretreatment with prazosin, an alpha-adrenergic antagonist . B . quintana LPS did not significantly change heart rate (HR), hematocrit (HCT) and platelet count in the above reported in vivo model, and regarding mean blood pressure (MAP) only a very early (5 min after LPS) and mild (yet significant) hypotension was observed . In contrast, a long-lasting decrease of MAP was found in Salmonella minnesota R595 LPS-treated animals . Blood TNFalpha levels did not change significantly from the baseline in rats injected with either saline or with B . quintana LPS, on the contrary S . minnesota R595 LPS-injected animals showed substantial increase of TNFalpha levels up to 2924 pg/ml at 60 min after LPS injection . B . quintana LPS as well as Salmonella LPS-injected rats exhibited an increase of the blood levels of GRO/CINC-1, particularly at 240 min after LPS administration . Apical part of rat gut villi showed several TUNEL-positive cells in tissue sections from B . quintana LPS-treated animals . Taken together, our data demonstrates that B . quintana LPS is able to selectively stimulate some inflammatory mediators . B . quintana LPS-induced leukocytosis appears mediated by an alpha-adrenergic receptor . The delayed apoptotic process of leukocytes and the chemokine increase may explain the apoptotic cells found in the rat gut and the inflammatory reactions in some human Bartonella diseases . This peculiar inflammatory pattern induced by B . quintana LPS, may partially account for the lack of severe septic shock, observed in human B . quintana infections.

Biochemistry, 2003 Jun 10, 42(22), 6719 - 25
New substrates for beta-lactam-recognizing enzymes: aryl malonamates; Cabaret D et al.; Aryl malonamates are demonstrated to be novel substrates of a broad range of beta-lactam-recognizing enzymes . These compounds are isomers of the aryl phenaceturates, which are well-known substrates of these enzymes, but the new compounds contain a retro-amide side chain . Several lines of evidence, including comparisons of steady-state kinetic parameters between enzymes and a detailed investigation of the methanolysis kinetics, solvent deuterium isotope effects, and pH-rate profile for turnover of a retro substrate by the Enterobacter cloacae P99 beta-lactamase, suggested that the new substrates are likely to be hydrolyzed by the same chemical mechanisms as "normal" substrates . Molecular modeling indicated that the retro-amide group fits snugly into the active site of the P99 beta-lactamase by hydrogen bonding to the conserved lysine-67 residue . The retro-amide side chain may represent a lead to novel mechanism-based and transition state analogue inhibitors.

Antonie Van Leeuwenhoek, 2003, 83(4), 341 - 9
Comparison of three molecular methods for typing Aeromonas popoffii isolates; Soler L et al.; Three typing methods, restriction fragment length polymorphism (RFLP) of the 16S-23S intergenic spacer region (ISR), PCR amplification of the enterobacterial repetitive intergenic consensus (ERIC) and of the repetitive extragenic palindromic units (REP), were evaluated for typing 26 isolates of Aeromonas popoffii from different geographical origins . When the methods were independently studied, ERIC showed the highest discriminatory power . When the methods were combined, the best combination of two methods was ERIC with REP since strains showed a tendency to cluster according to their geographical origin . However, this tendency was reinforced with the addition of ISR-RFLP.

J Bacteriol, 2003 Jun, 185(12), 3672 - 7
Altered substrate selection of the melibiose transporter (MelY) of Enterobacter cloacae involving point mutations in Leu-88, Leu-91, and Ala-182 that confer enhanced maltose transport; Shinnick SG et al.; We isolated mutants of Escherichia coli HS4006 containing the melibiose-H(+) symporter (MelY) from Enterobacter cloacae that had enhanced fermentation on 1% maltose MacConkey plates . DNA sequencing revealed three site classes of mutations: L-88-P, L-91-P, and A-182-P . The mutants L-88-P and L-91-P had 3.6- and 5.1-fold greater maltose uptake than the wild type and enhanced apparent affinities for maltose . Energy-coupled transport was defective for melibiose accumulation, but detectable maltose accumulation for the mutants indicated that active transport is dependent upon the substrate transported through the carrier . We conclude that the residues Leu-88, Leu-91 (transmembrane segment 3 {TMS-3}), and Ala-182 (TMS-6) of MelY mediate sugar selection . These data represent the first MelY mutations that confer changes in sugar selection.

J Nutr Sci Vitaminol (Tokyo), 2002 Dec, 48(6), 448 - 52
Biosynthesis of pyridoxine in Saccharomyces cerevisiae--origin of the pyridoxine nitrogen atom differs under anaerobic and aerobic conditions; Ishida S et al.; The amide nitrogen atom of glutamine is incorporated into pyridoxine in four eukaryotes (i.e., Emericella nidulans, Mucor racemosus, Neurospora crassa and Saccharomyces cerevisiae) and two prokaryotes (i.e., Staphylococcus aureus and Bacillus subtilis) . However, in the prokaryotes Pseudomonas putida, Enterobacter aerogenes and Escherichia coli, it is the nitrogen atom of glutamate that is incorporated into pyridoxine (J Nutr Sci Vitaminol (2000) 46, 55-57) . As these results were from experiments conducted under aerobic conditions, we investigated the biosynthesis of pyridoxine on S . cerevisiae under anaerobic conditions . The results showed that {amide-15N}L-glutamine was not incorporated into pyridoxine, unlike the results for aerobic conditions . The incorporation of {15N}ammonium salts into pyridoxine was not inhibited in the presence of casamino acids and tryptophan . The results showed that the nitrogen atoms of amino acids are not used for the biosynthesis of pyridoxine . The incorporation of 15N into pyridoxine was inhibited in the presence of adenine, but not in that of hypoxanthine . Thus, the nitrogen atom of pyridoxine may be from the amino group attached to the C-6 of adenine.

Mikrobiol Z, 2003 Jan-Apr, 65(1-2), 104 - 11
{Department of Biochemistry of Microorganisms--start of the path (1951-1973)}; Zakharova IIa; Creation of the Department of Biochemistry of Microorganisms at the Institute of Microbiology and Virology of the Academy of Sciences of Ukrainian SSR in the 30's of the last century was determined by a necessity of profound investigation of vital activity biochemism of microorganisms from various systematic groups which were studied in microbiological department of the Institute . Such complexity can explain certain diversity of the Department research at initial stages of its existence . The research of saccharose transformation into dextran Leuconostoc mesenteroides, when production solutions become slingy at sugar-refinaries, was one of the first most significant works of the Department . The enzyme saccharose-glycosyl-transferase performing this process was described for the first time . A cycle of works on the study of enzymes splitting lactose in milk under the effect of Streptococcus lactis has been carried out . Complex investigation of a number of proteins, polysaccharides, enzymes in enterobacteria has shown that the blocking of the enzyme aldolase is one of the reasons of alkali formation . A method has been developed for isolation of arenarin, antibiotic of plant origin, from sandy everlasting, the nature of its acting basis has been established . Nufarin, an active antibiotic, was isolated from the roots of white water lily when studying nitrogen fixation processes, special attention was given to interaction of hydrogenase and enzymes, taking part in nitrogen fixation, to the effect of ATP on these processes, ways of its synthesis, localization of ATPase in the cell membranes . Works on the study of lypopolysaccharides and polysaccharides of Gram-negative enterobacteria, bacteria of Pseudomonas genus were started with the purpose to use the obtained data to specify systematic propositions of the investigated microorganisms . Further on these works became the basis of thematic department . There are numerous reviews dedicated to their development.

Lik Sprava, 2003, (2), 39 - 41
{The incidence and antibiotic resistance of coagulase negative staphylococci isolated in pregnant women and newborns}; Nuruzova ZA et al.; Puerparae and newborns infants display an ever-increasing colonization with not only opportunistic enterobacteria but also coagulase-negative staphylococci that have a multiple resistance to antibiotics . In the study, the identification has been carried out of staphylococci, with their antibioticoresistance defined.

Nucleic Acids Res, 2003 Jun 1, 31(11), 2890 - 9
Experimental and computational analysis of transcriptional start sites in the cyanobacterium Prochlorococcus MED4; Vogel J et al.; In contrast to certain model eubacteria, little is known as to where transcription is initiated in the genomes of cyanobacteria, which are largely distinct from other prokaryotes . In this work, 25 transcription start sites (TSS) of 21 different genes of Prochlorococcus sp . MED4 were determined experimentally . The data suggest more than one TSS for the genes ftsZ, petH, psbD and ntcA . In contrast, the rbcL-rbcS operon encoding ribulose 1,5-bisphosphate carboxylase/oxygenase lacks a detectable promoter and is co-transcribed with the upstream located gene ccmK . The entire set of experimental data was used in a genome-wide scan for putative TSS in Prochlorococcus . A -10 element could be defined, whereas at the -35 position there was no element common to all investigated sequences . However, splitting the data set into sub-classes revealed different types of putative -35 boxes . Only one of them resembled the consensus sequence TTGACA recognized by the vegetative sigma factor (sigma70) of enterobacteria . Using a scoring matrix of the -10 element, more than 3000 TSS were predicted, about 40% of which were estimated to be functional . This is the first systematic study of transcription initiation sites in a cyanobacterium.

J Insect Physiol, 1997 Oct, 43(11), 1023 - 1029
Haemolymph proteins of larvae of Galleria mellonella detoxify endotoxins of the insect pathogenic bacteria Xenorhabdus nematophilus (Enterobacteriaceae); Halwani A et al.; Haemolymph of non-vaccinated Galleria mellonella larvae contains two proteins, LBP-1 (17.2kDa) and LBP-2 (26.0kDa) that:bond to the surfaces of the insect pathogenic bacteria, Xenorhabdus nematophilus;prevented lipid A-binding dye attaching to the lipid A of X . nematophilus endotoxin; andreduced endotoxin activity on the haemocytes.Protein LBP-1 also blocked the inhibition of prophenoloxidase activation by the endotoxins . It is proposed that proteins LBP-1 and LBP-2 are part of the containment responses of the insects to bacteria.

J Insect Physiol, 1997 Jun, 43(6), 513 - 519
Immune responses in Rhodnius prolixus: influence of nutrition and ecdysone; Azambuja P et al.; Starved larvae of Rhodnius prolixus, when challenged with Enterobacter cloacae B12, had their mortality related to their period of starvation . R . prolixus larvae fed on plasma alone, compared with insects fed on whole blood, had their immune reactivity affected as shown by: (i) a significant reduction in the ability to produce cecropin-like and lysozyme activities in the haemolymph when inoculated with E . cloacae; (ii) a reduction in numbers of haemocytes and nodule formation following challenge with bacteria; (iii) a decreased ability of plasma-fed insects in destroying their infection caused by inoculation of E . cloacae cells; and (iv) alpha-ecdysone therapy counteracted the immune depression in Rhodnius larvae fed on plasma alone . However, unlike other immune reactions, this set of experiments failed to demonstrate any interference of the plasma feeding on the prophenoloxidase-activating system, since melanin production was not reduced when the system was stimulated by the presence of bacteria in the haemolymph . The significance of these data is discussed in relation to the effect of diet components and the moulting hormone on the immune reactivity in insects.

J Insect Physiol, 1998 Dec, 44(12), 1173 - 1180
Long-term reduction of cold hardiness following ingestion of ice-nucleating bacteria in the Colorado potato beetle, Leptinotarsa decemlineata; Costanzo dagger JP et al.; We investigated the effect of ingestion of ice-nucleating bacteria on the supercooling capacity and cold hardiness of the Colorado potato beetle (Leptinotarsa decemlineata Say), a freeze-intolerant species that overwinters as adults in shallow, terrestrial burrows . Ingestion of ice-nucleating bacteria (Enterobacter agglomerans, Pseudomonas fluorescens, Pseudomonas putida, Pseudomonas syringae), fed on slices of potato tuber, caused an abrupt decrease in supercooling capacity . No change occurred in the supercooling capacity of beetles fed Escherichia coli, as this species lacks ice-nucleating activity . Ingestion rates showed that tubers treated with different species were equally palatable . During diapause induction beetles evacuated food from their guts, but nevertheless retained sufficient ice-nucleating bacteria to diminish supercooling . Beetles fed P . fluorescens and P . putida exhibited reduced supercooling even after an 8-wk exposure to simulated winter conditions . Furthermore, P . fluorescens was isolated 10-wk post-ingestion from diapausing beetles . Our data suggest that ingested bacteria may be retained by insects during entry into diapause and that the cold hardiness of candidate crop pests, such as L . decemlineata, may be reduced by feeding them ice-nucleating bacteria prior to winter diapause.

J Insect Physiol, 2000 Apr, 46(4), 563 - 572
Larval and pupal induction and N-terminal amino acid sequence of lysozyme from Heliothis virescens; Chung KT et al.; Fifth instar larvae and prepupae of Heliothis virescens (tobacco budworm) were injected with live Enterobacter cloacae and bled at different times after vaccination . Immune pupal hemolymph showed a 54 times increase in lysozyme activity when compared with normal larval hemolymph, and an 11 times increase of lysozyme activity when compared with immune larval hemolymph . Lysozyme activity of the normal pupal hemolymph increased as greatly as did lysozyme activity of the immune larval hemolymph after metamorphosis . The pupal immune response with regard to lysozyme was much greater than the larval immune response in H . virescens . Lysozyme was purified by heat treatment at 100 degrees C and a chromatography series that included reverse-phase HPLC . The molecular mass of H . virescens lysozyme was approximately 16 kDa by SDS-PAGE which is greater than other insect lysozymes and chicken lysozyme . Amino acid sequence of the N-terminus showed that H . virescens lysozyme is 82% homologous with lysozyme of Manduca sexta and Galleria mellonella . CNBr cleavage of H . virescens lysozyme produced 11 and 6 kDa peptide fragments indicating that one methionine was present, which was also supported by amino acid analysis . However, methionine was located at the carboxyl terminal side rather than the N-terminal side as judged by the N-terminal sequences of each peptide fragment . The residue 22 in most lepidopteran lysozymes is methionine, whereas H . virescens lysozyme had a leucine at residue 22 . There was an amino acid deletion near the carboxyl terminal side of H . virescens lysozyme as also found in Trichoplusia ni.

J Agric Food Chem, 2003 Jun 4, 51(12), 3609 - 13
Fate of selenate metabolized by Enterobacter taylorae isolated from rice straw; Zahir ZA et al.; Rice straw has been successfully tested as an effective organic source and a carrier of selenate {Se(VI)}-reducing bacteria to remove Se(VI) from agricultural drainage water . In this study, an Se(VI)-reducing bacterium identified as Enterobacter taylorae was isolated from rice straw and used to remove Se(VI) from a 0.5% tryptic soy broth (TSB) and high-salt (15.5 dS m(-)(1)) synthetic agricultural drainage water containing Se(VI) in a range of 500-5000 microg/L . Results showed that E . taylorae reduced 81-94% of the added Se(VI) to elemental Se {Se(0)} in the 0.5% TSB solution during a 5-day experiment . In the high-salt drainage water, Se(VI) reduction was rapid during a 9-day experiment . On the final day of the experiment, Se(0) {75%} and Se(-II) {19%} were the major forms of Se in the drainage water with small amounts of Se(VI), Se(IV), and volatile Se released . The pathway of Se(VI) reduction in the drainage water followed the order Se(VI) --> selenite {Se(IV)} --> Se(0) --> selenide {Se(-II)} . This study suggests that E . taylorae may be used to remediate high-salt Se(VI)-contaminated agricultural drainage water.

Biotechnol Bioeng, 2003 Jul 20, 83(2), 226 - 34
Asymmetric synthesis of L-homophenylalanine by equilibrium-shift using recombinant aromatic L-amino acid transaminase; Cho BK et al.; L-Homophenylalanine (L-HPA) was asymmetrically synthesized from 2-oxo-4-phenylbutyric acid (2-OPBA) and L-aspartate using a recombinant aromatic amino acid transaminase (AroAT) . To screen microorganisms having such an L-specific AroAT with a relaxed substrate inhibition in the asymmetric synthesis of unnatural amino acids, enrichment cultures were performed in a minimal media containing 50 mM L-HPA as a sole nitrogen source . To reduce the intracellular background synthetic activity by amino acid pools in the cells, a two-step screening method was used . The putative AroAT (i.e., AroATEs) from the screened Enterobacter sp . BK2K-1 was cloned, sequenced, and overexpressed in E . coli cells . The activity of the overexpressed AroATEs was 314-fold higher than that of the wild-type cell . The substrate specificities of the enzyme and homology search revealed that the cloned transaminase is true AroAT . The AroATEs showed a substrate inhibition by 2-OPBA from 40 mM in the asymmetric synthesis, which made it difficult to perform batch asymmetric synthesis of L-HPA at high concentrations of 2-OPBA . To avoid the substrate inhibition by 2-OPBA, intermittent addition of the solid-state substrate was attempted to obtain a high concentration of L-HPA . By using the cell extract (75 U) obtained from the recombinant E . coli harboring the AroATEs gene, the asymmetric synthesis of L-HPA at 840 mM of 2-OPBA resulted in >94% of conversion yield and >99% ee of L-HPA of optical purity . Due to the low solubility (<2 mM) of L-HPA in the reaction buffer, synthesized L-HPA was continuously precipitated in the reaction media, which drives the reaction equilibrium towards the product formation . After full completion of the reaction, L-HPA of high purity (>99% ee) was easily recovered by simple pH shift of the reaction media . This method can permit very efficient asymmetric synthesis of other unnatural amino acids using a single transaminase reaction .

J Hosp Infect, 2003 May, 54(1), 25 - 31
A seven-year survey of Klebsiella pneumoniae producing TEM-24 extended-spectrum beta-lactamase in Nice University Hospital (1994-2000); Giraud-Morin C et al.; The aim of this study was to investigate TEM-24-producing isolates of Klebsiella pneumoniae, and their clonal dissemination in Nice University Hospital . During the 1994-2000 period, a total of 263 non-repetitive isolates of ESBL-producing K . pneumoniae were collected . Most of these isolates were highly resistant in vitro to ceftazidime, cefotaxime and aztreonam, but susceptible to cefoxitin and imipenem . Resistance profile analysis revealed seven predominant antibiotypes (P1 to P7) . Isoelectric focusing evidenced beta-lactamase activity, with a chromosomal penicillinase (pl 7.7), and one or two additional enzymes with pls ranging from 5.4 to 8.2 identified as presumed TEM-1 pl 5.4, TEM-3 pl 6.3, TEM-24 pl 6.5, SHV-3 pl 7.0, SHV-4 pl 7.8, SHV-5 pl 8.2, or other unidentified beta-lactamases . Among these K . pneumoniae, 130 isolates produced TEM-24, and 115 of them were highly resistant in vitro to quinolones (antibiotype P1) . This phenotype was responsible for an outbreak in a medical intensive care unit from March to September 2000 . Four isolates submitted were genetical sequenced, and shared 99.9% homology with tem-24 (GenBank no . X 65253) . Pulsed-field gel electrophoresis and enterobacterial repetitive intergenic consensus polymerase chain reaction (PCR) (ERIC2-PCR) applied to 28 non-epidemic and six epidemic isolates yielded concordant results . Molecular typing revealed the persistence and dissemination of a single clone of TEM-24 producing K . pneumoniae in Nice Hospital during the seven-year study period.

Drugs Today (Barc), 2001 Jun, 37(6), 401 - 410
Gemifloxacin; Le TP et al.; Gemifloxacin is a novel antibiotic and the first fluoroquinolone with a pyrrolidine derivative at the C-7 position . Because of the added pyrrolidine substitute, gemifloxacin has an enhanced spectrum of activity against Gram-positive bacteria such as Streptococcus pneumoniae and Staphylococcus aureus, in addition to its activity against Gram-negative bacteria . Like other fluoroquinolones, gemifloxacin's mechanism of action focuses on inhibiting DNA gyrase and topoisomerase, thus preventing cellular replication . In addition, in vitro and in vivo data have shown that the compound exhibits excellent activity against Enterobacteriaceae and other respiratory pathogens . Furthermore, it has been demonstrated that gemifloxacin has potential activity in vitro against anaerobic bacteria . With a broad spectrum of activity, convenient once-daily administration, good bio-availability and tolerability, gemifloxacin will be an important addition to our armamentarium against a wide range of infections, from urinary tract infections to community-acquired pneumonia . (c) 2001 Prous Science . All rights reserved.

In Silico Biol, 2003, 3(1-2), 3 - 15 Epub 2002 Dec 30.
Bioinformatics classification and functional analysis of PhoH homologs; Kazakov AE et al.; PhoH protein is a putative ATPase belonging to the phosphate regulon in Escherichia coli . EC-PhoH homologs are present in different organisms, but it is not clear if they are functionally related, besides nothing is known about their regulation . To distinguish true functional orthologs of EC-PhoH in different classes of bacteria and to identify their functional role in bacterial metabolic network we performed phylogenetic analysis of these proteins and comparative study of position and regulation of the related genes . Three groups of proteins were identified . Proteins of the first group (BS-PhoH orthologs) are present in most of bacteria and are proposed to be functionally linked to phospholipid metabolism and RNA modification . Proteins of the second group (BS-YlaK orthologs) are present in most of aerobes and Actinobacterial YlaK orthologs are shown to be members of a fatty acid beta-oxidation regulons . EC-PhoH orthologs are classified in a third group, specific for Enterobacteria . Functional role of PhoH homologs in the lipid and RNA metabolism and proposed interrelation of PhoH paralogs in one organism are discussed.

Infect Immun, 2003 Jun, 71(6), 3607 - 13
Visualization of Proteus mirabilis morphotypes in the urinary tract: the elongated swarmer cell is rarely observed in ascending urinary tract infection; Jansen AM et al.; Proteus mirabilis, a common cause of nosocomial and catheter-associated urinary tract infection, colonizes the bladder and ascends the ureters to the proximal tubules of the kidneys, leading to the development of acute pyelonephritis . P . mirabilis is capable of swarming, a form of multicellular behavior in which bacteria differentiate from the short rod typical of members of the family Enterobacteriaceae, termed the swimmer cell, into hyperflagellated elongated bacteria capable of rapid and coordinated population migration across surfaces, called the swarmer cell . There has been considerable debate as to which morphotype predominates during urinary tract infection . P . mirabilis(pBAC001), which expresses green fluorescent protein in both swimming and swarming morphotypes, was constructed to quantify the prevalence of each morphotype in ascending urinary tract infection . Transurethral inoculation of P . mirabilis(pBAC001) resulted in ascending urinary tract infection and kidney pathology in mice examined at both 2 and 4 days postinoculation . Using confocal microscopy, we were able to investigate the morphotypes of the bacteria in the urinary tract . Of 5,087 bacteria measured in bladders, ureters, and kidneys, only 7 (0.14%) were identified as swarmers . MR/P fimbria expression, which correlates with the swimmer phenotype, is prevalent on bacteria in the ureters and bladder . We conclude that, by far, the predominant morphotype present in the urinary tract during ascending infection is the short rod-the swimmer cell.

Infect Immun, 2003 Jun, 71(6), 3221 - 6
Lipopolysaccharide-mimetic activities of a Toll-like receptor 2-stimulatory substance(s) in enterobacterial lipopolysaccharide preparations; Muroi M et al.; Lipopolysaccharide (LPS) preparations are known to often contain substances which activate cells through Toll-like receptor 2 (TLR2), and it is suspected that bacterial lipoproteins are responsible for this activation . We compared the mode of action of the TLR2-stimulatory substances with that of a synthetic bacterial lipopeptide (tripalmitoyl-Cys-Ser-Ser-Asn-Ala {Pam(3)CSSNA}), as well as with that of peptidoglycan . Six out of eight LPS preparations tested induced NF-kappaB-dependent reporter activity in 293 cells expressing CD14 and TLR2 . Phenol extract (PEX) prepared from Escherichia coli LPS by modified phenol extraction induced reporter activity in 293 cells expressing TLR2, and this activity was enhanced by coexpression of CD14, whereas the activity of Pam(3)CSSNA was not dependent on CD14 . The activity of PEX, but not that of Pam(3)CSSNA or peptidoglycan, was also enhanced by LPS binding protein or serum and blocked by polymyxin B . In addition, the activity of PEX was inhibited by a lipid A precursor (compound 406) in 293 cells expressing CD14 and TLR2 . These results indicate that E . coli LPS preparations contain LPS-mimetic TLR2-stimulatory substances which differ from bacterial lipopeptides or peptidoglycan.

Antimicrob Agents Chemother, 2003 Jun, 47(6), 1882 - 6
Treatment with a broad-spectrum cephalosporin versus piperacillin-tazobactam and the risk for isolation of broad-spectrum cephalosporin-resistant Enterobacter species; Schwaber MJ et al.; Receipt of a broad-spectrum cephalosporin is a strong risk factor for isolation of broad-spectrum cephalosporin-resistant Enterobacter species, and yet the risk from other broad-spectrum beta-lactams hydrolyzed by group 1 beta-lactamases has not been well characterized . We compared the risk conferred by broad-spectrum cephalosporins to that conferred by piperacillin-tazobactam, alone or in combination with an aminoglycoside or a fluoroquinolone . A retrospective cohort was monitored from treatment onset until a broad-spectrum cephalosporin-resistant Enterobacter strain was isolated or the patient was discharged . There were 447 patients in the piperacillin-tazobactam group and 2,341 patients in the broad-spectrum cephalosporin group . Groups were similar in age (mean, 62.5 years) . The piperacillin-tazobactam group had a smaller percentage of men (32% versus 44%, P < 0.001) and a lower rate of intensive care unit stay (25% versus 38%, P < 0.001) but a higher rate of surgery (41% versus 26%, P < 0.001) . Groups differed in the distribution of comorbidities . Resistant Enterobacter strains were isolated from 62 patients, 2% in each group (hazard ratio {RR} = 1.02 {P = 0.95}) . In multivariable analysis, risk was similar among treatment groups (RR = 0.71 {P = 0.32}) . Intensive care unit stay and surgery were associated with increased risk (RR = 4.53 {P < 0.001} and RR = 1.97 {P = 0.015}, respectively), fluoroquinolones were protective (RR = 0.24 {P = 0.003}), and aminoglycosides did not affect risk (RR = 0.98 {P = 0.95}) . The protective effect of fluoroquinolones against isolation of broad-spectrum cephalosporin-resistant Enterobacter spp . and the equivalence in risk associated with piperacillin-tazobactam and broad-spectrum cephalosporins may have important clinical and epidemiologic implications.

Pediatr Pharmacol (New York), 1982, 2(2), 121 - 5
Recommended amikacin doses in newborns often produce excessive serum levels; Philips JB 3rd et al.; Emergence of a multiply drug resistant Enterobacter cloacae during a seven-week period in 1980 caused amikacin to become the aminoglycoside of choice in the initial management of suspected sepsis in a neonatal intensive care unit . Recommended doses (7.5-10 mg/kg loading; 15 mg/kg in two divided doses IV) were given to 5 infants < or = 1,000 gm and to 13 larger babies . Trough levels 11.5 hours after a dose were 16.6 +/- 11.9 microg/ml in infants < or = 1,000 gm and 6.5 +/- 4.3 microg/ml in the larger infants (P < 0.02) . Peak levels one hour postinfusion exceeded 40 microg/ml in 3 of 5 < or = 1,000-gm babies and 4 of 12 > 1,000-gm infants (P = NS) . Overall, 7 of 10 peak and/or trough levels in < or = 1,000-gm infants were in the range considered toxic in adults, versus 7 of 24 in larger babies (P = 0.03) . These data show that surprisingly excessive blood levels of amikacin are likely in infants < or = 1,000 gm and may also occur in larger infants using currently recommended dosage schedules . These unexpected findings emphasize the need to monitor drug levels and individualize therapy in very low birthweight infants.

Zhonghua Yi Xue Za Zhi, 2003 Jan 10, 83(1), 42 - 5
{Chronic Helicobacter pylori infection induces apoptosis-resistance in gastric epithelial cells}; He XX et al.; OBJECTIVE: To establish a cell model by chronically infecting human gastric epithelial cells with H.pylori, and to determine the effect of chronic H.pylori infection on apoptosis of gastric epithelial cells . METHODS: Human non-tumor gastric epithelial cells GES-1 were cocultured with an H.pylori strain SS1 for 16 weeks, in order to obtain GES-1 "model" cells . Biological characteristics of the model cells including growth, adherence and clone formation were determined . Apoptosis of the "model" cells in response to apoptosis inducers such as H.pylori and other enterobacteria and agents commonly used in the chemotherapy of gastric cancer were measured by flow cytometry . RESULTS: A cell model of human gastric epithelial cells with chronic H.pylori infection (GES-1 model cells) was successfully established . Apoptosis was dramatically decreased in the "model" cells with and without stimulation by H.pylori and other enterobacteria and some chemotherapeutic agents . CONCLUSION: Chronic H.pylori infection induces apoptosis resistance in gastric epithelial cells, which may increase the risk of the development of gastric cancer.

Infez Med, 2002 Dec, 10(4), 230 - 5
{Outpatient parenteral antibiotic therapy (OPAT) of diabetic foot infections with piperacillin/tazobactam}; Marvaso A et al.; Treatment of diabetic foot infections (DFIs) represents an important challenge for surgeons, especially in light of the poor results achieved by traditional therapeutic approaches . In this study, the clinical and bacteriological efficacy of TZP for treatment of DFIs in 38 outpatients was evaluated . All patients (median age 63 yrs) were affected by DFIs to different degrees of severity according to Wagner's classification: degree 0, 7 pts; degree 1, 17 pts; degree 2, 10 pts; degree 3, 4 pts . Degree 0-1 infections underwent a 10-18 day course with TZP given i.m . (2.25 g bid); degree 2-3 infections were initially treated with TZP i.v . (4.5 g bid or tid) . Some patients began treatment in hospital and after early discharge continued parenteral therapy at home; others were treated exclusively at home . Some pts, after a 5-7-day course of i.v . therapy switched to i.m . route . The average duration of antibiotic therapy was 28 days . At the end of treatment with TZP, some patients underwent a new treatment with oral coamoxi-clav for 10-15 days . A bacteriological examination was done for all patients: ulcus (degree 1) and deep tissue (degree 2-3) swabs at the first surgical toilette . Clinical controls, medications, surgical toilettes and microbiological cultures were performed according to the degree of severity, extension of the lesion and response to treatment . All cultures were positive for polymicrobial infections (Staphylococcus spp, Enterococcus spp, Enterobacteriaceae, Pseudomonas spp) . In 30/38 pts (79%) a complete resolution was observed; in 4 pts (10%) an improvement . DFIs require long term parenteral treatment, with wide spectrum antibiotics including Gram +, Gram - and anaerobes . OPAT represents a valid alternative to hospitalisation when the general conditions of the patient are stable, the infection is not too severe and complications are not present . TZP proved to be a good choice for treatment of diabetic foot infections that, due to its high safety, can be successfully utilized also in OPAT programmes

Tissue Antigens, 2003 May, 61(5), 352 - 61
IgG reactive to CTL-directed epitopes of self-antigens is either lacking or unbalanced in atopic dermatitis patients; Kawamoto N et al.; We previously demonstrated that CTL-directed epitopes derived from non-mutated self-antigens elicit a type-I allergy in the majority of healthy donors (HD) as did the presence of IgE and IgG reactive to these peptides in the sera of the donors . We investigated in this study whether Igs reactive to eight types of CTL-directed peptides were elevated in the sera of 40 patients with atopic dermatitis (AD) . Total IgE levels in the sera of AD patients were significantly higher than those of HD, however, no significant differences between the AD patients and the HD were observed in either the serum levels or the positive rates of IgE reactive to seven of the eight peptides . Total IgG levels were not different from each other, however, IgG reactive to the two peptides with no sequence similarity to other species and one peptide that had similarity to DNA helicase II of enterobacteria were not detectable in the sera of the AD patients . Although IgG reactive to the remaining five peptides, which had sequence similarity to other species, were detectable in both the AD patients and the HD, ratios of peptide-specific IgG1/IgG2 were mostly lower in the AD patients than in the HD . These results indicate that IgG reactive to CTL-directed epitopes of self-antigens is either lacking or unbalanced in AD patients . This information may provide new insight into the immune-mechanisms of elevated auto-reactivity of AD patients.

Lett Appl Microbiol, 2003, 36(6), 362 - 71
Evaluation of biotracers to monitor effluent retention time in constructed wetlands; Hodgson CJ et al.; AIMS: With concern surrounding the environmental impact of chemical tracers on the aquatic environment, this paper presents the initial evaluation of biotracers used to determine the effluent retention time, an important performance indicator, in a Free Water Surface Constructed Wetland . METHODS AND RESULTS: Production of the biotracers, coliphage MS2, and the bacteriophage of Enterobacter cloacae and antibiotic resistant endospores of Bacillus globigii is described in detail . Their subsequent use in three separate tracer experiments - January, March and June (2000) - revealed the variability of retention time with respect to effluent flow . The biotracer MS2 showed the constructed wetland had a retention time of 8-9 h at a mean discharge of 0.9 l s-1, increasing to 10-12 h at a mean discharge 0.3 l s-1 . A similar retention of 9-10 h at a mean discharge of 0.3 l s-1 was calculated for the Ent . cloacae phage . In contrast, use of endospores revealed considerably longer retention times at these mean discharge rates; 12-24 h and 36-48 h, respectively . CONCLUSION: Biotracers could provide a useful and environmentally friendly technique to monitor effluent retention in constructed wetlands . At this stage the phage tracers appear particularly promising due to ease of isolation and recovery . SIGNIFICANCE AND IMPACT OF THE STUDY: Initial results are encouraging and have highlighted the potential of biotracers as alternatives to chemical tracers, even in microbially-rich waters.

J Appl Microbiol, 2003, 94(6), 1052 - 8
Correlation between bacterial haemoglobin gene (vgb) and aeration: their effect on the growth and alpha-amylase activity in transformed Enterobacter aerogenes; Khleifat K et al.; AIMS: To evaluate the effects of bacterial haemoglobin on bacterial growth and alpha-amylase formation under different aeration conditions . METHODS AND RESULTS: Enterobacter aerogenes was transformed with the gene encoding Vitreoscilla (bacterial) haemoglobin, vgb . The growth kinetics and ability to synthesize alpha-amylase enzyme were investigated in this transformed Enterobacter strain as well as in two other Enterobacter control strains that do not harbour the vgb gene . Such comparison was made under variable aeration conditions, using the agitation rate as a measure of aeration . The expression of bacterial haemoglobin-supported cell growth determined as O.D.600 and cell viability in addition to the alpha-amylase production . These positive effects of bacterial haemoglobin were observed under both low and high aerations, but at different extents . CONCLUSIONS: In addition to improving cell growth under low aeration, the bacterial haemoglobin is able to promote bacterial cell tolerance during exposure to high oxygen tension . SIGNIFICANCE AND IMPACT OF THE STUDY: The expression of bacterial haemoglobin is advantageous in reducing the burden of certain toxic conditions such as high oxygen levels . It may have the same impact on some environmental toxic substances . This, haemoglobin biotechnology can be extended to induce enzymes of pollutants degradation or production of some useful industrial substances.

Eur J Biochem, 2003 May, 270(10), 2322 - 31
Studies on structure-function relationships of indolepyruvate decarboxylase from Enterobacter cloacae, a key enzyme of the indole acetic acid pathway; Schutz A et al.; Enterobacter cloacae, isolated from the rhizosphere of cucumbers, produces large amounts of indole-3-acetic acid . Indolepyruvate decarboxylase, the key enzyme in the biosynthetic pathway of indole-3-acetic acid, catalyses the formation of indole-3-acetaldehyde and carbon dioxide from indole-3-pyruvic acid . The enzyme requires the cofactors thiamine diphosphate and magnesium ions for catalytic activity . Recombinant indolepyruvate decarboxylase was purified from the host Escherichia coli strain JM109 . Specificity of the enzyme for the substrates indole-3-pyruvic acid, pyruvic acid, benzoylformic acid, and seven benzoylformic acid analogues was investigated using a continuous optical assay . Stopped-flow kinetic data showed no indication for substrate activation in the decarboxylation reaction of indole-3-pyruvic acid, pyruvic acid or benzoylformic acid . Size exclusion chromatography and small angle X-ray solution scattering experiments suggested the tetramer as the catalytically active state and a pH-dependent subunit association equilibrium . Analysis of the kinetic constants of the benzoylformic acid analogues according to Hansch et al . {Hansch, C., Leo, A., Unger, S.H., Kim, K.H., Nikaitani, D & Lien, E.J . (1973) J . Med . Chem.16, 1207-1216} and comparison with indole-3-pyruvic acid conversion by pyruvate decarboxylases from Saccharomyces cerevisiae and Zymomonas mobilis provided some insight into the catalytic mechanism of indolepyruvate decarboxylase.

Eur J Biochem, 2003 May, 270(10), 2312 - 21
Crystal structure of thiamindiphosphate-dependent indolepyruvate decarboxylase from Enterobacter cloacae, an enzyme involved in the biosynthesis of the plant hormone indole-3-acetic acid; Schutz A et al.; The thiamin diphosphate-dependent enzyme indolepyruvate decarboxylase catalyses the formation of indoleacetaldehyde from indolepyruvate, one step in the indolepyruvate pathway of biosynthesis of the plant hormone indole-3-acetic acid . The crystal structure of this enzyme from Enterobacter cloacae has been determined at 2.65 A resolution and refined to a crystallographic R-factor of 20.5% (Rfree 23.6%) . The subunit of indolepyruvate decarboxylase contains three domains of open alpha/beta topology, which are similar in structure to that of pyruvate decarboxylase . The tetramer has pseudo 222 symmetry and can be described as a dimer of dimers . It resembles the tetramer of pyruvate decarboxylase from Zymomonas mobilis, but with a relative difference of 20 degrees in the angle between the two dimers . Active site residues are highly conserved in indolepyruvate/pyruvate decarboxylase, suggesting that the interactions with the cofactor thiamin diphosphate and the catalytic mechanisms are very similar . The substrate binding site in indolepyruvate decarboxylase contains a large hydrophobic pocket which can accommodate the bulky indole moiety of the substrate . In pyruvate decarboxylases this pocket is smaller in size and allows discrimination of larger vs . smaller substrates . In most pyruvate decarboxylases, restriction of cavity size is due to replacement of residues at three positions by large, hydrophobic amino acids such as tyrosine or tryptophan.

Eur J Cell Biol, 2003 Apr, 82(4), 193 - 200
Outer membrane protein A (OmpA) activates human epidermal Langerhans cells; Godefroy S et al.; Outer membrane protein (Omp)A is highly represented and conserved in the Enterobacteriaceae family . Using a recombinant OmpA from Klebsiella pneumoniae (kpOmpA), we have analysed the interaction between this bacterial cell wall protein and human Langerhans cells (LC), the antigen-presenting cells of the epidermis and mucosa . We showed that biotinylated kpOmpA binds to human LC freshly isolated from epidermis . kpOmpA up-regulated MHC class II, CD86 and CCR7 expression, enhanced migration in response to macrophage inflammatory protein-3beta (MIP-3beta) through a reconstituted basement membrane mimicking the prerequisite passage through the dermal-epidermal basement membrane on the way to lymph nodes . The allostimulatory function of kpOmpA-treated LC was more potent than that of untreated cells . Even though the proportion of LC which binds kpOmpA was shown to vary between individuals, our data indicate that kpOmpA binds to and activates LC, and suggest that recognition of OmpA by LC may be an initiating event in the antibacterial host response.

Pediatr Nephrol, 2003 Jul, 18(7), 714 - 7 Epub 2003 May 15.
Pamidronate in a girl with chronic renal insufficiency dependent on parenteral nutrition; Duke JL et al.; A 10-year-old 40-kg African-American female with megacystis microcolon hypoperistalsis syndrome maintained on total parenteral nutrition (TPN), with a history of metabolic bone disease and renal insufficiency, was admitted with a Candida parapsilosis central venous line infection . During her 280-day hospital stay, she had multiple episodes of bacteremia and recurrent candidemia . Furthermore, she developed pathological fractures and hip displacement with osteomyelitis due to Enterobacter . Hypercalcemia and a history of nephrocalcinosis had prevented appropriate dosing of calcium prior to and during the first months of her hospital stay . Pamidronate and chlorothiazide were added to her regimen . The urinary calcium to creatinine ratio and ionized calcium decreased . The pamidronate dose was increased to 60 mg once a week and was well tolerated . Daily calcium was added to her TPN solution and was increased to 10 mEq/day by the time of discharge . We conclude that relatively large doses of pamidronate may be required in certain cases of refractory hypercalcemia and are well tolerated in children.

Infez Med, 1998, 6(2), 71 - 80
Antibiotic prophylaxis in the surgical patient; Thadepalli H et al.; Antimicrobial selection for prophylaxis in surgery is based on the site of surgery, likely pathogen involved in addition to the in vitro efficacy, pharmacokinetics and the cost of the drugs used . For example, prophylactic agent in cardiovascular or orthopedic and skin and soft tissue surgery must cover against Staphylococcus aureus as well as the enterobacteriaceae; cephalosporins being adequate . On the other hand, any drug used in cases of urologic surgery must be excreted by the kidney in an active state and should also be active against E . coli, a common uropathogen such as any cephalosporins or penicillin . Drugs like macrolides and tetracyclines accumulate in the prostate and are good for prostate surgery by they are not excreted well by the kidney and therefore useless for urological prophylaxis . It is important to note that even treating minor infections in a neurosurgical patient, we must use an antibiotic that cross blood-brain barrier otherwise meningitis might develop . In cases of gastrointestinal tract, surgery on the colon and appendix requires special coverage against anaerobic bacteria especially Bacteroides fragilis . On the other hand surgery on the stomach, gall-bladder and upper two thirds of small intestine, it is adequate to use drugs to cover aerobic bacteria such as E . coli . Most studies show that a single most effective antibiotic is enough and it is unnecessary to use two or more drug combinations.

J Clin Invest, 2003 May, 111(10), 1589 - 602
Surfactant proteins A and D inhibit the growth of Gram-negative bacteria by increasing membrane permeability; Wu H et al.; The pulmonary collectins, surfactant proteins A (SP-A) and D (SP-D), have been reported to bind lipopolysaccharide (LPS), opsonize microorganisms, and enhance the clearance of lung pathogens . In this study, we examined the effect of SP-A and SP-D on the growth and viability of Gram-negative bacteria . The pulmonary clearance of Escherichia coli K12 was reduced in SP-A-null mice and was increased in SP-D-overexpressing mice, compared with strain-matched wild-type controls . Purified SP-A and SP-D inhibited bacterial synthetic functions of several, but not all, strains of E . coli, Klebsiella pneumoniae, and Enterobacter aerogenes . In general, rough E . coli strains were more susceptible than smooth strains, and collectin-mediated growth inhibition was partially blocked by coincubation with rough LPS vesicles . Although both SP-A and SP-D agglutinated E . coli K12 in a calcium-dependent manner, microbial growth inhibition was independent of bacterial aggregation . At least part of the antimicrobial activity of SP-A and SP-D was localized to their C-terminal domains using truncated recombinant proteins . Incubation of E . coli K12 with SP-A or SP-D increased bacterial permeability . Deletion of the E . coli OmpA gene from a collectin-resistant smooth E . coli strain enhanced SP-A and SP-D-mediated growth inhibition . These data indicate that SP-A and SP-D are antimicrobial proteins that directly inhibit the proliferation of Gram-negative bacteria in a macrophage- and aggregation-independent manner by increasing the permeability of the microbial cell membrane.

Infez Med, 1999, 7(4), 231 - 237
{Bacterial pneumonia in HIV-infected patients}; Cocchi L et al.; Patients and methods: This is a retrospective study performed on HIV-positive patients discharged from our Institution from January 1993 through December 1998 with a diagnosis of bacterial pneumonia . Cases of TB or atypical micobacterial infection were excluded from this analysis . Causative organisms were identified, when possible, by taking into account positive cultures from diverse sources (blood, sputum, pleural fluid and others) . Results: In the 6-yr period we considered, 120 patients were identified . Among them, we were able to obtain clinical and imaging data on 98 cases . Focal infiltrates on chest X-ray studies were present in 87.7% of cases, 24.5% had a pleural effusion, 9.2% nodular lesions, 4.1% cavitary images and in 2 patients only hilar lymphadenopaties were noted . Causative agents resulted to be S . aureus (14 cases); P . aeruginosa (11); S . pneumoniae (6); R . equi (4); Enterobacter spp . and K . pneumoniae (3 cases each); E . coli, Peptostreptococcus spp and Enterococcus spp . (1 case each) . No causative organism was isolated in 54 patients (55.1%) and the diagnosis was based on clinical and therapeutical grounds . Around half of cases (46.9%) responded well to therapy, while 11 (11.2%) died because of the lung infection . In 3 cases other opportunistic infections were the cause of death and 22 cases of relapse were recorded as well . Five patients resulted lost to follow-up . Conclusions: This retrospective study demonstrated a high prevalence of S . aureus lung infections along with the presence of otherwise rare causative organisms such as R . equi . Radiologic appearance of lung lesions did not differ substantially from the one of HIV negative patients . A relatively good response to antibiotic therapy was also noted.

J Food Prot, 2003 May, 66(5), 878 - 81
Microbial quality of ostrich carcasses produced at an export-approved South African abattoir; Karama M et al.; The aim of this study was to evaluate the microbial quality of ostrich carcasses produced in a South African export-approved ostrich abattoir . Ninety surface samples were collected from 30 ostrich carcasses at three processing points in the abattoir: after skinning, after evisceration, and after chilling . Samples were evaluated for aerobic plate counts, for levels of Pseudomonas spp., Enterobacteriaceae, and Staphylococcus aureus, and for the presence of Escherichia coli . Surface counts (means +/- standard deviations) at postskinning, postevisceration, and postchilling processing points were, respectively, 4.32 +/- 0.62, 4.21 +/- 0.63, and 4.57 +/- 0.48 log CFU/cm2 for total aerobes; 2.82 +/- 1.65, 2.86 +/- 1.53, and 3.75 +/- 0.94 log CFU/ cm2 for Pseudomonas spp.; 2.89 +/- 0.78, 2.90 +/- 0.53, and 2.38 +/- 0.67 log CFU/cm2 for S . aureus; and 2.55 +/- 1.53, 2.78 +/- 1.31, and 2.73 +/- 1.46 log CFU/cm2 for Enterobacteriaceae . Statistically significant differences were detected between the counts for the postskinning and postchilling processing points and between the counts for the postevisceration and postchilling processing points for total aerobes, Pseudomonas spp., and S . aureus . Of practical significance was the increase in Pseudomonas spp . counts on samples collected after chilling . Seventeen of 90 samples (18.8%) tested positive for E . coli . Counts for E . coli-positive samples ranged from 1.0 to 3.79 log CFU/cm2, with a mean count of 2.15 +/- 0.94 log CFU/cm2 . The majority of the samples testing positive for E . coli were collected after evisceration.

J Food Prot, 2003 May, 66(5), 723 - 31
Improved detection of Salmonella spp . in foods by fluorescent in situ hybridization with 23S rRNA probes: a comparison with conventional culture methods; Fang Q et al.; This report describes a new technique for the detection and identification of Salmonella species in food with the use of fluorescent in situ hybridization (FISH) with 23S rRNA-targeted oligonucleotide probes . Two species-specific 23S rRNA-targeted oligonucleotide probes (Sal-1 and Sal-3) were selected, and one (Sal-544) was newly designed . The relative specificities of these probes were compared with those of bacterial 23S rRNA sequences from the GenBank database and tested by in situ hybridization with bacterial cell smears of pure cultures . Fifty-one tested reference strains of Salmonella serovars belonging to subspecies I (enterica) hybridized with these probes . No cross-reactions with 46 other strains of the family Enterobacteriaceae or with another 14 bacterial strains from other families were observed . Storage of a Salmonella Panama test strain under various environmental conditions (2, 5, and 15% NaC1; -20 degrees C, 4 degrees C, and room temperature; pHs of 3.3 to 7.4) did not adversely affect the FISH method . No matrix effects were observed with 18 different kinds of foods . FISH was able to detect Salmonella spp . in 52 (probe Sal-1), 56 (probe Sal-3), and 35 (probe Sal-544) of 225 naturally contaminated food samples after 16 h of incubation in a preenrichment broth . When conventional culture and detection methods were used, Salmonella could be isolated from only 30 of these 225 samples . In contrast, FISH failed to identify Salmonella in only two of the culture-positive samples when Sal-1 and Sal-3 were used and in only three of the culture-positive samples when Sal-544 was used.

Curr Top Microbiol Immunol, 2003, 272, 3 - 35
Molecular evolution of adenoviruses; Benko M et al.; New advances in the field of genetic characterization of adenoviruses originating from different animal species are summarized . Variations seen in the host range and specificity, pathogenicity, genomic arrangement or gene complement are much wider than expected based on previous studies of human adenoviruses . Several exceptional adenoviruses from the two traditional conventional genera are now removed, and proposed to form at least two new genera . The eventual host origin of the new genera, however, is not clarified . Novel results from the genomic and phylogenetic analyses of adenoviruses originating from lower vertebrate species (including reptiles, amphibians and fish) seem to imply that probably five major clusters of adenoviruses exist corresponding to the five major classes of Vertebrata . Adenoviruses, which are now suspected to have common origin with enterobacterium phages from the family Tectiviridae, are perhaps very ancient indeed, and may have undergone a co-evolution with vertebrate hosts.

Mycol Res, 2003 Feb, 107(Pt 2), 198 - 205
PCR-based DNA fingerprinting indicates host-related genetic variation in the nematophagous fungus Pochonia chlamydosporia; Morton CO et al.; The mitosporic fungus Pochonia chlamydosporia is a potential biocontrol agent for cyst (Heterodera spp . and Globodera spp.) and root knot (Meloidogyne spp.) nematodes, which are important agricultural plant pests . 54 isolates from diverse geographical regions and several nematode hosts were used in this study . Genetic variation was examined using enterobacterial repetitive intergenic consensus (ERIC) primed PCR and sequences from the internal transcribed spacer (ITS) rRNA region . ERIC PCR yielded 35 scorable binary characters from all the fungi tested and cluster analysis of the data showed that isolates from cyst nematodes were more genetically variable than those from root knot nematodes . The ITS regions were highly conserved, the only significant difference being an extra thymidine in isolates from Meloidogyne spp . Assays with nematode eggs indicated that isolates differ in their ability to infect different nematode genera . The results indicate host related variation in P . chlamydosporia . This finding has significant implications for the application of P . chlamydosporia as a biocontrol agent.

Pediatr Hematol Oncol, 2003 Jun, 20(4), 281 - 9
The changing pattern of bloodstream infection in pediatric oncology patients in the United Arab Emirates; Trad O et al.; A surveillance study was performed on the pattern and antimicrobial susceptibilities of microorganisms isolated from blood cultures in the main pediatric oncology unit in the United Arab Emirates . The only previous data were published in 1995 . During 1998-2000, the pattern of bloodstream infection changed . Enterobacter spp . and Enterococcus spp . emerged as frequent pathogens, while Pseudomonas aeruginosa became less common . There was a high incidence (65/198) of polymicrobial bacteremia not previously reported . This study highlights the need for continuous surveillance of the pattern of bloodstream infection in pediatric oncology patients so that changes may be detected and antimicrobial treatment modified appropriately.

Int J Environ Health Res, 2003 Mar, 13(1), 31 - 42
The microbiological quality of ready-to-eat foods with added spices; Little CL et al.; A microbiological study of ready-to-eat foods with added spices or spice ingredients was undertaken to identify any risk factors in the production, storage and display of this product and to establish their effect on microbiological quality . Examination of 1946 ready-to-eat foods from sandwich bars, cafes, public houses, restaurants, specialist sandwich producers, bakers, delicatessens, market stalls and mobile vendors found that 1291 (66%) were of satisfactory/acceptable microbiological quality, 609 (32%) were of unsatisfactory quality, and 46 (2%) were of unacceptable quality . Unacceptable results were due to high levels of B . cereus and/or other Bacillus spp . (>/=10(5) cfu g(-1)) . Unsatisfactory results were mostly due to high Aerobic Colony Counts (up to >/=10(7) cfu g(-1)), Enterobacteriaceae (>/=10(4) cfu g(-1)), Escherichia coli (>/=10(2) cfu g(-1)), and Bacillus spp (>/=10(4) cfu g(-1)) . Examination of 750 spices and spice ingredients revealed that B . cereus were present in 142 (19%) samples, other Bacillus spp . in 399 (53%) samples, and Salmonella spp . (S . enteritidis PT 11) in one (<1%) sample . Approximately a third (222) of spice and spice ingredients examined contained high counts (>/=10(4) cfu g(-1)) of B . cereus and/or other Bacillus spp., and appeared to be associated with the corresponding ready-to-eat foods containing similar high counts of these organisms (P<0.0001) . Acceptable microbiological quality of ready-to-eat foods to which spices or spice ingredients have been added was associated with premises that had management food hygiene training and hazard analysis in place . Poor microbiological quality was associated with preparation on the premises, premises type, little or no confidence in the food business management of food hygiene, and small premises as indicated by local authority inspectors' confidence in management and consumer at risk scores.

Int J Food Microbiol, 2003 Jun 25, 83(3), 263 - 80
Relation between microbiological quality, metabolite production and sensory quality of equilibrium modified atmosphere packaged fresh-cut produce; Jacxsens L et al.; The quality of four types of fresh-cut produce, packaged in consumer-sized packages under an equilibrium modified atmosphere and stored at 7 degrees C, was assessed by establishing the relation between the microbial outgrowth and the corresponding production of nonvolatile compounds and related sensory disorders.In vitro experiments, performed on a lettuce-juice-agar, demonstrated the production of nonvolatile compounds by spoilage causing lactic acid bacteria and Enterobacteriaceae . Pseudomonas fluorescens and yeasts, however, were not able to produce detectable amounts of nonvolatile metabolites.The type of spoilage and quality deterioration in vivo depended on the type of vegetable . Mixed lettuce and chicory endives, leafy tissues, containing naturally low concentrations of sugars, showed a spoilage dominated by Gram-negative microorganisms, which are not producing nonvolatile compounds . Sensory problems were associated with visual properties and the metabolic activity of the plant tissue . Mixed bell peppers and grated celeriac, on the other hand, demonstrated a fast and intense growth of spoilage microorganisms, dominated by lactic acid bacteria and yeasts . This proliferation resulted in detectable levels of organic acids and the rejection by the trained sensory panel was based on the negative perception of the organoleptical properties (off-flavour, odour and taste).The applied microbiological criteria corresponded well with detectable changes in sensory properties and measurable concentrations of nonvolatile compounds, surely in the cases where lactic acid bacteria and yeasts were provoking spoilage . Consequently, the freshness of minimally processed vegetables, sensitive for outgrowth of lactic acid bacteria and yeasts (e.g., carrots, celeriac, bell peppers, mixtures with non-leafy vegetables) can be evaluated via analysis of the produced nonvolatile compounds.

J Biol Chem, 2003 May 16, 278(20), 17752 - 9 Epub 2003 Mar 05.
Structural analysis of the DNA-binding domain of the Erwinia amylovora RcsB protein and its interaction with the RcsAB box; Pristovsek P et al.; The transcriptional regulator RcsB interacts with other coactivators to control the expression of biosynthetic operons in enterobacteria . While in a heterodimer complex with the regulator RcsA the RcsAB box consensus is recognized, DNA binding sites for RcsB without RcsA have also been identified . The conformation of RcsB might therefore be modulated upon interaction with various coactivators, resulting in the recognition of different DNA targets . We report the solution structure of the C-terminal DNA-binding domain of the RcsB protein from Erwinia amylovora spanning amino acid residues 129-215 solved by heteronuclear magnetic resonance (NMR) spectroscopy . The C-terminal domain is composed of four alpha-helices where two central helices form a helix-turn-helix motif similar to the structures of the regulatory proteins GerE, NarL, and TraR . Amino acid residues involved in the RcsA independent DNA binding of RcsB were identified by titration studies with a RcsAB box consensus fragment . Data obtained from NMR spectroscopy together with surface plasmon resonance measurements demonstrate that the RcsAB box is specifically recognized by the RcsAB heterodimer as well as by RcsB alone . However, the binding constant of RcsB alone at target promoters from Escherichia coli, E . amylovora, and Pantoea stewartii was approximately 1 order of magnitude higher compared with that of the RcsAB heterodimer . We present evidence that the obvious role of RcsA is not to alter the DNA binding specificity of RcsB but to stabilize RcsB-DNA complexes.

Microb Ecol, 2003 Jul, 46(1), 122 - 33 Epub 2003 May 13.
Transformation of Azospirillum brasilense Cd with an ACC deaminase gene from enterobacter cloacae UW4 fused to the Tet r gene promoter improves its fitness and plant growth promoting ability; Holguin G et al.; It has been reported that PGPB, containing ACC deaminase, can cleave the plant ethylene precursor ACC and thereby lower ethylene concentration in a developing or stressed plant, protecting it against the deleterious effects of stress ethylene and facilitating the formation of longer roots . In a previous work we have demonstrated expression of the ACC deaminase gene ( acdS) from Enterobacter cloacae UW4 under the control of the lac promoter in Azospirillum brasilense Cd . With the inference that a construct including the ACC deaminase gene under the control of a constitutive promoter weaker than the lac promoter might impose less metabolic load on Azospirillum and improve its fitness, it was decided to clone acdS under the control of a tetracycline resistance gene promoter . The ACC deaminase structural gene was fused to the Tet(r) gene promoter by overlap extension using PCR, cloned in pRK415, and transferred into A . brasilense Cd . The resulting transformants showed lower ACC deaminase activity than those with the lac promoter controlled acdS gene . However, acdS under the control of the Tet(r) gene promoter imposed lesser metabolic load on Azospirillum brasilense Cd . The result was significantly increased IAA synthesis and greater bacterial growth rate, as well as increased ability to survive on the surface of tomato leaves and to promote the growth of tomato seedlings.

Vector Borne Zoonotic Dis, 2002 Fall, 2(3), 197 - 9
Moellerella wisconsensis isolated from the oral cavity of a wild raccoon (Procyon lotor); Sandfort RF et al.; This report describes the isolation of Moellerella wisconsensis from the oral secretions of a wild raccoon in Northern California . Human enteric disease has previously been associated with this organism . This represents the first isolation of this rare enterobacterial species from a non-captive animal and only the third from a non-human source.

J Clin Microbiol, 2003 May, 41(5), 2197 - 200
Extended-spectrum beta-lactamase enzymes in clinical isolates of Enterobacter species from Lagos, Nigeria; Aibinu IE et al.; Over a 9-month period, 8 of 40 nonduplicate isolates of Enterobacter spp . producing extended-spectrum beta-lactamase (ESBL) were detected for the first time from two hospitals in Lagos, Nigeria . Microbiologic and molecular analysis confirmed the presence of ESBL . Only four isolates transferred ESBL resistance as determined by the conjugation test, and pulsed-field gel electrophoresis showed genetically unrelated isolates.

J Clin Microbiol, 2003 May, 41(5), 2096 - 101
Evaluation of the Vitek 2 ID-GNB assay for identification of members of the family Enterobacteriaceae and other nonenteric gram-negative bacilli and comparison with the Vitek GNI+ card; O'Hara CM et al.; We evaluated the Vitek 2 ID-GNB identification card (bioMerieux, Inc., Durham, N.C.) for its ability to identify members of the family Enterobacteriaceae and other gram-negative bacilli that are isolated in clinical microbiology laboratories . Using 482 enteric stock cultures and 103 strains of oxidase-positive, gram-negative glucose-fermenting and nonfermenting bacilli that were maintained at -70 degrees C and passaged three times before use, we inoculated cards according to the manufacturer's directions and processed them in a Vitek 2 instrument using version VT2-R02.03 software . All panel identifications were compared to reference identifications previously confirmed by conventional tube biochemical assays . At the end of the initial 3-h incubation period, the Vitek 2 instrument demonstrated an accuracy of 93.0% for the identification of enteric strains; 414 (85.9%) were correctly identified at probability levels ranging from excellent to good, and an additional 34 (7.1%) strains were correctly identified but at a low level of discrimination . Nineteen (3.9%) strains were unidentified, and 15 (3.1%) were misidentified . The 19 unidentified strains were scattered among 10 genera . Three of the 15 misidentified strains were lactose-positive Salmonella spp . and were identified as Escherichia coli; another was a lactose-positive, malonate-negative Salmonella enterica subsp . arizonae strain that was identified as E . coli . Of the 103 glucose-fermenting and nonfermenting nonenteric strains, 88 (85.4%) were correctly identified at probability levels ranging from excellent to good, and 10 (9.7%) were correctly identified, but at a low level of discrimination, for a total of 95.1% accuracy with this group . Two strains were unidentified and three were misidentified . The errors occurred for strains in three different genera . With the increased hands-off approach of the Vitek 2 instrument and accuracies of 93% for the identification of enteric organisms and 95.1% for the identification of nonenteric organisms with the ID-GNB card, use of this product presents an acceptable method for the identification of most gram-negative organisms commonly isolated in the clinical laboratory . A comparison of these results to those obtained by testing 454 of the same strains with the Vitek GNI+ card revealed no significant difference in the abilities of the two cards to identify these organisms accurately.

J Clin Microbiol, 2003 May, 41(5), 1912 - 8
Quality control for beta-lactam susceptibility testing with a well-defined collection of Enterobacteriaceae and Pseudomonas aeruginosa strains in Spain; Canton R et al.; Eighteen Enterobacteriaceae and Pseudomonas aeruginosa strains, 16 of them with well-defined beta-lactam resistance mechanisms, were sent to 52 Spanish microbiology laboratories . Interpretative categories for 8 extended-spectrum beta-lactams were collected . Participating laboratories used their own routine susceptibility testing procedures (88% automatic systems, 10% disk diffusion, and 2% agar dilution) . Control results were established by two independent reference laboratories by applying the NCCLS microdilution method and interpretative criteria . Interpretative discrepancies were observed in 16% of the results (4.4% for cefepime, 3.0% for aztreonam, 2.8% for piperacillin-tazobactam, 1.7% for cefotaxime {CTX} and ceftazidime, 1.1% for ceftriaxone, 0.9% for meropenem, and 0.3% for imipenem) . High consistency with reference values (<5% of major plus very major errors) was observed with (i) American Type Culture Collection quality control strains; (ii) strains with low-efficiency mechanisms inactivating extended-spectrum beta-lactams, such as OXA-1-producing Escherichiacoli or SHV-1-hyperproducing Klebsiella pneumoniae; (iii) strains with highly efficient mechanisms, such as SHV-5 porin-deficient K . pneumoniae, CTX-M-10 in Enterobacter cloacae hyperproducing AmpC, and P . aeruginosa with the MexAB OprM efflux phenotype or hyperproducing AmpC . Low consistency (>30% major plus very major errors) was detected in K1-producing Klebsiella oxytoca, CTX-M-9-producing E . coli, and in OprD(-) P . aeruginosa strains . Extended-spectrum beta-lactamase (ESBL)-producing strains accounted for 86% of very major errors . Recognition of the ESBL phenotype was particularly low in Enterobacter cloacae strains (<35%), due to the lack of NCCLS-specific rules in this genus . A K1-producing K . oxytoca was misidentified by 10% of laboratories as an ESBL producer . The use of well-defined resistant strains is useful for improving proficiency in susceptibility testing in clinical laboratories.

Curr Microbiol, 2003 May, 46(5), 365 - 70
Polymorphism in the yclC-rpoS region of enterobacteria; Martinez-Garcia E et al.; The nucleotide sequence downstream from the rpoS gene in Enterobacter cloacae and Kluyvera cryocrescens contains the slyA-pad1-yclC genes . The DNA sequence of Enterobacter cloacae CETC960 shows a 2.6-kb insertion of unknown origin between rpoS and slyA . This 2.6-kb sequence has also been detected in species of Salmonella and in Pseudomonas aeruginosa, but not in the same location . This insertion has been detected in all the Enterobacter cloacae clinical strains studied although the size of the rpoS-yclC region was highly variable, possibly owing to the presence of insertions and/or deletions . The study of the rpoS-mutS region in other enterobacteria also showed variability in size . Our results support the idea of a variational hot spot in the rpoS-mutS region that could be related to pathogenesis and horizontal transfer.

Environ Sci Technol, 2003 Apr 15, 37(8), 1509 - 14
Environmental fate of roxarsone in poultry litter . I . Degradation of roxarsone during composting; Garbarino JR et al.; Roxarsone, 3-nitro-4-hydroxyphenylarsonic acid, is an organoarsenic compound that is used extensively in the feed of broiler poultry to control coccidial intestinal parasites, improve feed efficiency, and promote rapid growth . Nearly all the roxarsone in the feed is excreted unchanged in the manure . Poultry litter composed of the manure and bedding material has a high nutrient content and is used routinely as a fertilizer on cropland and pasture . Investigations were conducted to determine the fate of poultry-litter roxarsone in the environment Experiments indicated that roxarsone was stable in fresh dried litter; the primary arsenic species extracted with water from dried litter was roxarsone . However, when water was added to litter at about 50 wt % and the mixture was allowed to compost at 40 degrees C, the speciation of arsenic shifted from roxarsone to primarily arsenate in about 30 days . Increasing the amount of water increased the rate of degradation . Experiments also suggested that the degradation process most likely was biotic in nature . The rate of degradation was directly proportional to the incubation temperature; heat sterilization eliminated the degradation . Biotic degradation also was supported by results from enterobacteriaceae growth media that were inoculated with litter slurry to enhance the biotic processes and to reduce the concomitant abiotic effects from the complex litter solution . Samples collected from a variety of litter windrows in Arkansas, Oklahoma, and Maryland also showed that roxarsone originally present had been converted to arsenate.

Diagn Microbiol Infect Dis, 2003 Apr, 45(4), 287 - 93
Occurrence and antimicrobial susceptibility patterns of pathogens isolated from skin and soft tissue infections: report from the SENTRY Antimicrobial Surveillance Program (United States and Canada, 2000); Rennie RP et al.; A total of 1,404 bacterial isolates were recovered from skin and soft tissue infections (SSTIs) from hospitalized patients in 24 sites in the United States (US) and 5 Canadian medical centers as part of the SENTRY Antimicrobial Surveillance Program . Isolates were collected between October and December, 2000 . The rank order of pathogens was: Staphylococcus aureus (45.9%), Pseudomonas aeruginosa (10.8%), Enterococcus spp . (8.2%), Escherichia coli (7.0%), Enterobacter spp . (5.8%) and Klebsiella spp . (5.1%) . The same order was observed in the US and Canada . Of note, almost 30% of S . aureus were oxacillin-resistant . Vancomycin resistance among enterococci was low (7.8%) representing a marked decrease from earlier SENTRY Program reports . Several antimicrobial agents remained very active against P . aeruginosa and Enterobacteriaceae isolates . In particular amikacin, cefepime, and the carbapenems (imipenem and meropenem) showed an excellent spectrum of activity (>95% susceptible) . Extended-spectrum beta-lactamase production was observed in both E . coli (7.1%) and Klebsiella spp . (11.3%) . Cefepime remained highly active, even against ceftazidime-resistant isolates of Enterobacter spp . The results of this study have identified the most common causes of SSTIs in hospitalized patients in North America, and can be used to make informed decisions concerning standards of empiric treatment for SSTIs in this region.

FEMS Microbiol Lett, 2003 Apr 25, 221(2), 243 - 8
Stable integration and expression of mosquito-larvicidal genes from Bacillus thuringiensis subsp . israelensis and Bacillus sphaericus into the chromosome of Enterobacter amnigenus: a potential breakthrough in mosquito biocontrol; Tanapongpipat S et al.; Previously, we have successfully integrated a spectinomycin/streptomycin resistance gene into Enterobacter amnigenus strain An11, a potential host for mosquito control, using in vivo recombination via homologous recombination (An11S4::Omega) . We now report the successful transfer of two mosquito-larvicidal genes, cry4B from Bacillus thuringiensis subsp . israelensis and binary toxin genes from Bacillus sphaericus, into the host genome . To facilitate the screening procedure, the E . amnigenus derivative, An11S4::Omega, was used as a host . The integration of both toxin genes by two successive crossover events interrupted the Omega region yielding two integrants designated An11S4::cry4B and An11S4::Omega::bin, respectively . Differences in the integration efficiency of these toxin genes were observed . The presence of both genes in the target sites of the host genome was verified by PCR . Cry4B was expressed weakly from An11S4::cry4B, but no expression of the binary toxin gene could be detected from An11S4::Omega::bin . Nevertheless, these two integrants exhibited mosquito-larvicidal activity against Aedes and Culex, suggesting that both proteins were expressed, but at very low levels.

J R Soc Health, 2003 Mar, 123(1), 39 - 45
The survival and recovery of bacteria in vacuum cleaner dust; Haysom IW et al.; The possibility exists that environmental dust could be a source of gastro-intestinal infection in the domestic environment and that the causative microbes are collected during vacuum cleaning . This study examines the survival of total bacterial populations, Enterobacteriaceae and salmonella species in vacuum cleaner dust in vitro and in use . Total counts remain constant at around 10(6)-10(8) colony forming units (cfu) g-1 for at least 60 days . Enterobacteriaceae showed only a slight decline over the same period . Recovery of salmonellae artificially inoculated into vacuum dust was dose and time dependent: even relatively small inocula (< 100 cfu g-1) were recoverable more than one month after inoculation . Questionnaires and vacuum cleaner dust samples were received from 76 households . A significant association was found between total bacterial counts and whether the household was in a rural or urban situation and the number of people in the household . No association was found between total bacterial counts and the number of children in the household, the presence of pets, wearing shoes indoors, the makes, model and age of the vacuum cleaner, the type of dust collector or dust bag, how often the vacuum cleaner was used and the length of time between sample collection and microbiological testing . Salmonella species were isolated from vacuum cleaner dust from three of the 76 households although no factors could be identified linking the homes . This study shows that vacuum cleaners are effective collectors and reservoirs of microbial contamination and that these contaminants are able to survive for up to two months . Vacuum cleaner dust could thus be a useful indicator of environmental contamination in the home.

J Med Microbiol, 2003 May, 52(Pt 5), 427 - 33
Molecular epidemiology of an outbreak of multiresistant Klebsiella pneumoniae in a Tunisian neonatal ward; Ben-Hamouda T et al.; During the first quarter of 1996, a major outbreak of clinical infection caused by multiresistant Klebsiella pneumoniae (MRKP) occurred in the neonatal ward of the 'Maternite Wassila Bourguiba' in Tunis, Tunisia . In total, 32 isolates of MRKP, comprising 23 clinical isolates and nine surveillance isolates, were recovered during this period and analysed for epidemiological relatedness . The isolates were compared with 17 other isolates of MRKP that were recovered during 1995 . Macrorestriction profiles of total genomic DNA following XbaI restriction endonuclease digestion were analysed by PFGE; this typing classified 56% of the 32 isolates recovered in 1996 into two major clusters . Cluster A included ten isolates from 1996 and three isolates recovered in 1995, whereas cluster B included eight isolates from the outbreak of 1996 . The remaining isolates were genetically unrelated to those of clusters A and B; they constituted sporadic strains . The two major clusters were also evident using other molecular typing methods, such as random amplification of polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus (ERIC)-PCR, where isolates of clusters A and B could be identified on the basis of their discriminative patterns . This investigation showed the predominance of two epidemic strains, and illustrated the ease with which MRKP strains can disseminate and persist within a single ward.

J Med Microbiol, 2003 May, 52(Pt 5), 421 - 5
Prevalence of extended-spectrum beta-lactamase-producing Gram-negative bacteria in septicaemic neonates in a tertiary care hospital; Jain A et al.; The present study was undertaken to investigate the high incidence of multiresistant Gram-negative bacilli causing neonatal septicaemia . Samples of neonatal blood from 728 suspected cases were obtained in brain heart infusion broth with sodium polyanethol sulfonate . All Gram-negative rods isolated were subsequently subjected to routine antimicrobial susceptibility testing and tests for extended-spectrum beta-lactamase (ESBL) production, as per NCCLS recommendations . ESBL was detected in 86.6% of Klebsiella spp., 73.4% of Enterobacter spp . and 63.6% of Escherichia coli strains . It was also observed that 74.4-80.9% of these ESBL producers were resistant to cefotaxime and 47.6-59.5% were resistant to ceftazidime in routine susceptibility testing . Some ESBL producers (36.3-61.5%) were found to be susceptible to either or both cephalosporins used in this study . It is concluded that indiscriminate use of third-generation cephalosporins may be responsible for the selection of ESBL-producing multiresistant strains in the neonatal intensive-care unit (NICU).

J Biol Chem, 2003 Jul 11, 278(28), 25618 - 27 Epub 2003 Apr 25.
Identification of a cross-reactive epitope widely present in lipopolysaccharide from enterobacteria and recognized by the cross-protective monoclonal antibody WN1 222-5; Muller-Loennies S et al.; Septic shock due to infections with Gram-negative bacteria is a severe disease with a high mortality rate . We report the identification of the antigenic determinants of an epitope that is present in enterobacterial lipopolysaccharide (LPS) and recognized by a cross-reactive monoclonal antibody (mAb WN1 222-5) regarded as a potential means of treatment . Using whole LPS and a panel of neoglycoconjugates containing purified LPS oligosaccharides obtained from Escherichia coli core types R1, R2, R3, and R4, Salmonella enterica, and the mutant strain E . coli J-5, we showed that mAb WN1 222-5 binds to the distal part of the inner core region and recognizes the structural element R1-alpha-d-Glcp-(1-->3)-{l-alpha-d-Hepp-(1-->7)}-l-alpha-d-Hepp 4P-(1-->3)-R2 (where R1 represents additional sugars of the outer core and R2 represents additional sugars of the inner core), which is common to LPS from all E . coli, Salmonella, and Shigella . WN1 222-5 binds poorly to molecules that lack the side chain heptose or lack phosphate at the branched heptose . Also molecules that are substituted with GlcpN at the side chain heptose are poorly bound . Thus, the side chain heptose and the 4-phosphate on the branched heptose are main determinants of the epitope . We have determined the binding kinetics and affinities (KD values) of the monovalent interaction of E . coli core oligosaccharides with WN1 222-5 by surface plasmon resonance and isothermal titration microcalorimetry . Affinity constants (KD values) determined by SPR were in the range of 3.6 x 10-5 to 3.2 x 10-8 m, with the highest affinity being observed for the core oligosaccharide from E . coli F576 (R2 core type) and the lowest KD values for those from E . coli J-5 . Affinities of E . coli R1, R3, and R4 oligosaccharides were 5-10-fold lower, and values from the E . coli J-5 mutant were 29-fold lower than the R2 core oligosaccharide . Thus, the outer core sugars had a positive effect on binding.

Zh Mikrobiol Epidemiol Immunobiol, 2000 Jul-Aug, (4 Suppl), 85 - 8
{Microbial biocenosis in the mucous membranes of the nose and the middle ear in patients with purulent otitis}; Usviatsov BIa et al.; 25 biocenoses of the microflora of the mucous membranes of the nose and the middle ear in patients having acute and chronic purulent otitis media (epi- and mesotympanitis) were studied . The dynamic study was carried out at the peak of the manifestations of clinical symptoms and on convalescence or improvement of the state of patients . In the process of convalescence the normalization of the composition of the microflora of the nose and the middle ear was found to occur in patients having acute otitis as compared with those having chronic otitis . In chronic otitis dysbiosis was observed in the microflora of the nose and the middle ear (the preservation of Staphylococcus aureus and enterobacterial strains with increased capacity for persistence) . Correlation between the taxonomic composition and the biological properties of the microflora of the nose and the middle ear was established . Changes in the properties of individual strains of the microflora in the bacterial interaction of symbionts were more pronounced in the acute form of otitis than in the chronic one.

Zh Mikrobiol Epidemiol Immunobiol, 2000 Jul-Aug, (4 Suppl), 80 - 2
{Effect of water-soluble vitamins on the anti-lysozyme activity of enterobacteria}; Valyshev AV et al.; The influence of vitamins of group B (B1, B6, B12) and vitamin C on the antilysozyme activity (ALA) of pathogenic and opportunistic bacteria (Salmonella, Klebsiella, Escherichia coli) has been determined in a number of in vitro experiments . In E . coli vitamins had different influence on ALA: vitamins B1 and C (at a concentration of 5 mg/ml) increased this activity in E . coli, while vitamins B12 and C (at concentrations of 0.5 and 0.05 mg/ml) decreased it . In Klebsiella vitamins B1, B12 and C (at a concentration of 0.05 mg/ml) decreased ALA, while after the addition of vitamin C at concentrations of 0.5 and 5 mg/ml into the medium ALA increased . In Salmonella vitamins of group B had no influence on ALA, ascorbic acid at a low concentration (0.5 mg/ml) decreased their capacity for inactivating lysozyme . In enterobacteria vitamin B6 produced no changes in ALA.

Zh Mikrobiol Epidemiol Immunobiol, 2000 Jul-Aug, (4 Suppl), 12 - 6
{Role of bacterial protease degrading secretory immunoglobulin A in Klebsiella persistence}; Bondarenko VM et al.; During the study of 186 K . pneumoniae clinical strains the presence of SIgA-protease activity was detected in 109 isolates (58.6%) . The PCR test system permitting the detection of iga gene DNA in K . pneumoniae strains isolated in purulent inflammatory processes of different localization was developed . For the first time a conjugative plasmid with a mol . wt . of 100 MD was detected in K . pneumoniae clinical isolates . This plasmid controlled the capacity of inactivating SIgA, carried the markers of antibiotic resistance and was capable of expression in a wide circle of hosts belonging to the family Enterobacteriaceae . The results of in vitro experiments revealed that the strains containing plasmid SIgA were cytotoxic with respect to cells HEp-2 and more resistant to the digestive action of enzymes produced by the phagolysosomes of guinea pig peritoneal cells . As shown on the in vivo biological model with the use of the genetically linked pair of Salmonella typhimurium 274 vaccine strains, differing in SIgA-protease activity, plasmid pSigA ensured more prolonged survival of bacteria in mice in comparison with the nonplasmid variant . The study of SIgA-protease activity of K . pneumoniae strains circulating among patients with a view to the detection of clones causing the development of persistent infection was shown to have good prospects.

Jpn J Infect Dis, 2003 Feb, 56(1), 1 - 7
A two-year analysis of risk factors and outcome in patients with bloodstream infection; Endimiani A et al.; A two-year analysis was performed at our hospital to evaluate the incidence and clinical impact of bloodstream infections (BSI) in medical, surgical, and intensive care unit patients . During 1999-2000 there were 521 cases of BSI with an incidence of 10.1/1,000 admissions . The most frequent predisposing factors for BSI were intravascular catheter (56.4%) and previous use of antibiotics (50.9%) . Infections were considered as primary in 67.9% of cases . Urinary tract and intravascular catheter were the most frequent source of secondary bacteremia (43.1% and 35.9%, respectively) . At the time of the first positive blood culture, 83.5% of patients were receiving empirical treatment, but it was adequate in only 53.9% of cases . After antimicrobial susceptibility testing, adequate antibiotic treatment was given in 67.9% of cases . Statistical analysis of independent risk factors showed that mortality was significantly related to age (P < 0.048), rapidly-fatal diseases (P < 0.001), septic shock (P < 0.020), multiorgan failure (P < 0.001), previous use of antibiotics (P < 0.008), Enterobacteriaceae producing extended-spectrum beta-lactamases (P < 0.036), and inadequate empirical treatment (P < 0.039) . Based on local epidemiology and susceptibility data, microbiology laboratories should periodically release recommendations on the optimal empirical treatment for different wards.

Infez Med, 2000, 8(2), 66 - 74
{Cefuroxime stability to beta-lactamases: clinical implications}; Amicosante G et al.; Bacteria continuously evolve their resistance mechanisms to antibiotics, either in community or in the hospital setting . Production of beta-lactamases is one of the oldest way to overcome antimicrobial agents activity, since it was first described in 1944 immediately after the penicillin discovery . Beta-lactamases are enzymes hydrolysing the beta-lactam nucleus of beta-lactam antibiotics by using two strategies: a nucleophilic attack of a serine residue or activating a water molecule via a Zn++ . Cefuroxime is a injectable cephalosporin which can be also orally administered as a pro-drug named cefuroxime axetil . Cefuroxime has been classified as a second generation cephalosporin, even though the strict subgrouping of cephalosporins into classes is critically discussed by the Authors . Cefuroxime was the first beta-lactam with a higher stability to beta-lactamase hydrolysis due to its methoxy-imino side chain in position 7 of the cephem nucleus . Many of the clinically significant bacterial species producing beta-lactamases such as Haemophilus, Moraxella, Staphylococci and most Enterobacteriaceae then remain susceptible to cefuroxime . The more evoluted enzymes such as carbapenemases, extended-spectrum beta-lactamases or over-expressed cephalosporinases hydrolyse nearly all the beta-lactams antibiotics including cefuroxime . The available literature on the bacterial susceptibility to cefuroxime in Italy and use of cefuroxime in clinical settings where beta-lactamase producing bacteria could be involved has been analysed in the review . In conclusion, cefuroxime still represents a valid therapeutic option even in presence of most of the beta-lactamase producing bacteria.

Antimicrob Agents Chemother, 2003 May, 47(5), 1672 - 80
Trends in antimicrobial susceptibilities among Enterobacteriaceae isolated from hospitalized patients in the United States from 1998 to 2001; Karlowsky JA et al.; Longitudinal surveillance of Enterobacteriaceae for antimicrobial susceptibility is important because species of this family are among the most significant and prevalent human pathogens . To estimate rates of in vitro antimicrobial susceptibility among hospitalized patients in the United States, data from The Surveillance Network were studied for 14 agents tested against 10 species of Enterobacteriaceae (n = 384,279) isolated from intensive-care-unit (ICU) patients and non-ICU inpatients from 1998 to 2001 . Cumulative susceptibility (percent) data for all species of Enterobacteriaceae isolated from ICU patients and non-ICU inpatients, respectively, were ranked as follows: ampicillin-sulbactam (45.5 and 57.2) << ticarcillin-clavulanate (74.8 and 83.5) < trimethoprim-sulfamethoxazole (87.0 and 84.5) congruent with cefotaxime (82.9 and 92.6) = ceftazidime (82.3 and 91.0) = ceftriaxone (86.5 and 93.9) = piperacillin-tazobactam (83.5 and 90.5) < levofloxacin (89.3 and 90.6) = ciprofloxacin (91.0 and 91.7) < gentamicin (91.8 and 94.3) < cefepime (95.0 and 97.9) < amikacin (98.5 and 99.2) < imipenem (100 and 100) = meropenem (100 and 100) . Of those agents studied only susceptibilities to ciprofloxacin (94 to 89%) and levofloxacin (93 to 89%) decreased in a stepwise manner from 1998 to 2001 . Decreased fluoroquinolone susceptibility was most pronounced for Escherichia coli, Proteus mirabilis, and Enterobacter cloacae . For all species of Enterobacteriaceae, trimethoprim-sulfamethoxazole resistance was more commonly observed in isolates with a single-drug resistance phenotype while gentamicin and fluoroquinolone resistances were more common in isolates resistant to at least one additional class of antimicrobial agent . Ongoing surveillance of Enterobacteriaceae will be particularly important to monitor changes in fluoroquinolone susceptibility, as well as changes in the prevalence of isolates resistant to multiple classes of antimicrobial agents.

Antimicrob Agents Chemother, 2003 May, 47(5), 1652 - 7
In vitro and in vivo activities of AM-112, a novel oxapenem; Jamieson CE et al.; AM-112 {(1'R,5R,6R)-3-(4-amino-1,1-dimethyl-butyl)-6-(1'-hydroxyethyl)oxapenem-3-carboxylate} is a novel oxapenem compound which possesses potent beta-lactamase-inhibitory properties . Fifty-percent inhibitory concentrations (IC(50)s) of AM-112 for class A enzymes were between 0.16 and 2.24 micro M for three enzymes, compared to IC(50)s of 0.008 to 0.12 micro M for clavulanic acid . Against class C and class D enzymes, however, the activity of AM-112 was between 1,000- and 100,000-fold greater than that of clavulanic acid . AM-112 had affinity for the penicillin-binding proteins (PBPs) of Escherichia coli DC0, with PBP2 being inhibited by the lowest concentration of AM-112 tested, 0.1 micro g/ml . Ceftazidime was combined with AM-112 at 1:1 and 2:1 ratios in MIC determination studies against a panel of beta-lactamase-producing organisms . These studies demonstrated that AM-112 was effective at protecting ceftazidime against extended-spectrum beta-lactamase-producing strains and derepressed class C enzyme producers, reducing ceftazidime MICs by 16- and 2,048-fold . Similar results were obtained when AM-112 was combined with ceftriaxone, cefoperazone, or cefepime in a 1:2 ratio . Protection of ceftazidime with AM-112 was maintained against Enterobacter cloacae P99 and Klebsiella pneumoniae SHV-5 in a murine intraperitoneal sepsis model . The 50% effective dose of ceftazidime against E . cloacae P99 and K . pneumoniae SHV-5 was reduced from >100 and 160 mg/kg of body weight to 2 and 33.6 mg/kg, respectively, when it was combined with AM-112 at a 1:1 ratio . AM-112 demonstrates potential as a new beta-lactamase inhibitor.

Antimicrob Agents Chemother, 2003 May, 47(5), 1555 - 9
Modification of outer membrane protein profile and evidence suggesting an active drug pump in Enterobacter aerogenes clinical strains; Gayet S et al.; Two clinical strains of Enterobacter aerogenes that exhibited phenotypes of multiresistance to beta-lactam antibiotics, fluoroquinolones, chloramphenicol, tetracycline, and kanamycin were investigated . Both strains showed a porin pattern different from that of a susceptible strain, with a drastic reduction in the amount of the major porin but with an apparently conserved normal structure (size and immunogenicity), together with overproduction of two known outer membrane proteins, OmpX and LamB . In addition, the full-length O-polysaccharide phenotype was replaced by a semirough Ra phenotype . Moreover, in one isolate the intracellular accumulation of chloramphenicol was increased in the presence of the energy uncoupler carbonyl cyanide m-chlorophenylhydrazone, suggesting an energy-dependent efflux of chloramphenicol in this strain . The resistance strategies used by these isolates appear to be similar to that induced by stress in Escherichia coli cells.

Infez Med, 2000, 1(8), 18 - 23
{Fifty years of cephalosporins: rationale for success}; Cornaglia G; The cephalosporins constitute the antibiotic class possibly showing the widest flexibility of usage, due to their very great versatility in terms of molecular features, antibacterial spectrum, and administration schedules . In this half-century, cephalosporins have undoubtedly figured as one of the most commonly used and most successful classes of antibiotics against a vast range of bacterial infections . Cephalosporin activity against Gram-positive bacteria is generally good and, above all, largely predictable on the basis of the epidemiological data . Methicillin-resistant staphylococci and enterococci, of course, are excluded from their spectrum of action . Despite the diffusion of resistance mechanisms among Gram-negative organisms, mostly broad- and extended-spectrum beta-lactamases, cephalosporins are still highly effective against the vast majority of H . influenzae, Enterobacteriaceae and, albeit to a lesser extent, Pseudomonas spp . The growing diffusion of resistance, however, makes thorough assessment of antibiotic assay data mandatory, especially for Gram-negative strains isolated from departments at particularly high risk . Observance of these basic precautions may contribute towards the improved use of cephalosporins and towards maintaining their substantial efficacy in the face of the disturbing worldwide increase in resistance to all known antibiotics.

Biosens Bioelectron, 2003 May, 18(5-6), 751 - 4
Potential for detection of microorganisms and heavy metals in potable water using electronic nose technology; Canhoto OF et al.; Studies have been carried out to determine the potential for the detection of different microbial species (Enterobacter aerogenes, Escherichia coli, Pseudomonas aeruginosa), alone and in the presence of low concentrations of different heavy metals (As, Cd, Pb and Zn) in bottled, reverse osmosis (RO) and tap water, using an electronic nose . Studies show that it is possible to discriminate control water samples from water contaminated with 0.5 ppm of a mixture of metals . The presence of heavy metals may modify the activity of microorganisms and thus the volatile production patterns . Bacterial species at 10(2)-10(4) colony forming units (CFUs) ml(-1) could be detected after 24 h of incubation . Work is in progress to identify the limits of detection for a range of other microorganisms, including, fungi and cyanobacteria, and chlorinated phenols using electronic nose technology.

Res Microbiol, 2003 Apr, 154(3), 183 - 9
Invasion of insect blood tissue by Xenorhabdus bovienii; Owuama CI; Xenorhabdus species are entomopathogenic Gram-negative bacteria that belong to the family Enterobacteriaceae . They exist in two main phenotypic variations referred to as phase I and phase II . Invasion studies showed that Xenorhabdus bovienii phase I, unlike phase II, adhered to and were phagocytosed by Drosophila melanogaster malignant blood neoplasm, mbn-2 . The ingested bacteria within the phagosome multiplied and escaped into the mbn-2 cytoplasm . Further bacterial multiplication occurred within the cytoplasm with a longer postinvasion incubation period, resulting in mbn-2 lysis . X . bovienii multiplied more rapidly in artificial media than in mbn-2 . The generation time of phase I X . bovienii in the artificial media was 2.5- to 3-fold that in mbn-2 . Cell free extract of X . bovienii phase I fluoresced under UV light, unlike that of phase II.

Arch Biochem Biophys, 2003 May 1, 413(1), 139 - 46
Purification and partial characterization of azoreductase from Enterobacter agglomerans; Moutaouakkil A et al.; Azoreductase, an enzyme catalyzing the reductive cleavage of the azo bond of methyl red (MR) and related dyes, was purified to electrophoretic homogeneity from Enterobacter agglomerans . This bacterial strain, isolated from dye-contaminated sludge, has a higher ability to grow, under aerobic conditions, on culture medium containing 100mg/L of MR . The enzyme was purified approximately 90-fold with 20% yield by ammonium sulfate precipitation, followed by three steps of column chromatography (gel-filtration, anion-exchange, and dye-affinity) . The purified enzyme is a monomer with a molecular weight of 28,000 Da . The maximal azoreductase activity was observed at pH 7.0 and at 35 degrees C . This activity was NADH dependent . The K(m) values for both NADH and MR were 58.9 and 29.4 microM, respectively . The maximal velocity (V(max)) was 9.2 micromol of NADH min(-1)mg(-1) . The purified enzyme is inhibited by several metal ions including Fe(2+) and Cd(2+).

Saudi Med J, 2003 Mar, 24(3), 261 - 4
Multi-drug resistance of Escherichia coli from the urinary tract; Rafay AM et al.; OBJECTIVE: Resistance to antimicrobials of different structural classes has arisen in a multitude of bacterial species . This may complicate the therapeutic management of infections, including those of the urinary tract . The aim of this study is to show that antibiotic resistance surveillance is essential . METHODS: A total of 11,126 urine samples were received at Sultan Qaboos University Hospital (SQUH), Muscat, Sultanate of Oman, for one year period (2001), they were cultured for bacterial pathogen and sensitivity was performed for all significant isolates . RESULTS: Eight hundred and eighty-four samples were culture positive with Escherichia coli (E.coli) (N=445) as the most common enterobacteriaceae, followed by Klebsiella pneumoniae (N=161), unidentified Coliforms (N=56) and Klebsiella species (N=33) . High rate of resistance to b-Lactams was seen for all Enterobacteriaceae, maximum resistance was against ampicillin (78.6%) followed by co-amoxiclav (44.6%), but cefuroxime demonstrated the least resistance . Resistance to quinolone ranged from 4.7%-21.2% for all Enterobacteriaceae, cotrimoxazole resistance for all Enterobacteriaceae was 32.1% . Multi-drug resistance of E.coli was analyzed, 11.2% (50 of 445) were resistant to 3 or more antimicrobials and considered multidrug resistant . Among the multidrug-resistant isolates, 88% were resistant co-amoxiclav or cotrimoxazole, gentamicin 62%, ciprofloxacin 66%, and nitrofurantoin 32% . The predominant phenotype among multidrug-resistant isolates (26%; 13 of 50) included resistance to co-amoxiclav, gentamicin, and cotrimoxazole . This was the most common phenotype followed by 20%, of co-amoxiclav, cotrimoxazole and ciprofloxacin . CONCLUSION: In view of the current prevalence of multi-drug resistance among urinary tract isolates of E.coli at the SQUH (11.2%), continued surveillance will be beneficial.

Am J Respir Crit Care Med, 2003 Jul 1, 168(1), 77 - 84 Epub 2003 Apr 17.
Influence of systemic inflammatory response syndrome and sepsis on outcome of critically ill infected patients; Alberti C et al.; The clinical significance of the systemic inflammatory response in infected patients remains unclear . We examined risk factors for hospital mortality in 3,608 intensive care unit patients included in the European Sepsis Study . Patients were categorized as having infection without or with (i.e., sepsis) systemic inflammatory response, severe sepsis, and septic shock, on the first day of infection . Hospital mortality varied from 25 to 60% according to sepsis stage, but did not differ between the first two categories (hazard ratio, 0.94; p = 0.55), whereas there was a grading of severity from sepsis to severe sepsis (1.53, p < 10-4) and septic shock (2.64, p < 10-4) . Within each stage, mortality was unaffected by the number of inflammatory response criteria . Prognostic factors identified by Cox regression included comorbid conditions, severity of acute illness and acute organ dysfunction, shock, nosocomial infection, and infection caused by aerobic gram-negative bacilli, enterobacteria, Staphylococcus aureus, and infection from a digestive or unknown source . We conclude that whereas the categorization of infection by the presence of organ dysfunction or shock has strong prognostic significance, infection and sepsis have similar outcomes, unaffected by the presence or number of inflammatory response criteria . Refinement of risk stratification of patients presenting with infection and no organ dysfunction is needed.

Infez Med, 2002 Mar, 10(1), 16 - 20
{Cefotaxime, des-Cefotaxime and Ceftazidime: in vitro activity and stability to hydrolysis from tem-derived extended spectrum beta-lactamases}; Segatore B et al.; Beta-lactams represent one of the most important class of antibiotics for the treatment of infectious diseases due to pathogenic bacteria . The selective pressure exerted from the wide spread use of third generation cephalosporins generated mutant beta-lactamases belonging mainly to the TEM or SHV family that are able to extend the activity spectrum of hydrolysis . Moreover, extended spectrum cephalosporins are often a good choice in clinical practice towards Enterobacteriaceae . Here we report a comparative analysis of stability between cefotaxime, desacetyl-cefotaxime and ceftazidime with some common TEM-derivatives extended spectrum beta-lactamases.

Biol Bull, 2003 Apr, 204(2), 221 - 31
Genome evolution in an insect cell: distinct features of an ant-bacterial partnership; Wernegreen JJ et al.; Bacteria that live exclusively within eukaryotic host cells include not only well-known pathogens, but also obligate mutualists, many of which occur in diverse insect groups such as aphids, psyllids, tsetse flies, and the ant genus Camponotus (Buchner, 1965; Douglas, 1998; Moran and Telang, 1998; Baumann et al., 2000; Moran and Baumann, 2000) . In contrast to intracellular pathogens, these primary (P) endosymbionts of insects are required for the survival and reproduction of the host, exist within specialized host cells called bacteriocytes, and undergo stable maternal transmission through host lineages (Buchner, 1965; McLean and Houk, 1973) . Due to their long-term host associations and close phylogenetic relationship with well-characterized enterobacteria (Fig . 1), P-endosymbionts of insects are ideal model systems to examine changes in genome content and architecture that occur in the context of beneficial, intracellular associations . Since these bacteria have not been cultured outside of the host cell, they are difficult to study with traditional genetic or physiological approaches . However, in recent years, molecular and computational approaches have provided important insights into their genetic diversity and ecological significance . This review describes some recent insights into the evolutionary genetics of obligate insect-bacteria symbioses, with a particular focus on an intriguing association between the bacterial endosymbiont Blochmannia and its ant hosts.

Mikrobiologiia, 2003 Jan-Feb, 72(1), 111 - 6
{Nitrogen-fixing activity in peat soils from a raised bog}; Kravchenko IK et al.; The nitrogenase (acetylene reductase) activity in monolithic and minced peat samples was found to be low, no more than 0.014-0.022 mg N/(kg h) . Incorporation of the 15N2 isotope into organic compounds of peat soil was from 2.71-8.13 mg N/kg over 15 days . The nitrogen-fixing activity was the highest in a 10-20 cm layer of soil and much lower in the upper (under green moss) and deeper (20-30 cm) layers . The addition of glucose to soil samples stimulated nitrogen fixation considerably after 18-26 h . The maximum nitrogenase activity (3.5-3.8 mg N/(kg h)) observed after 60-70 h coincided with the peak of respiratory activity . A repeated addition of glucose after its exhaustion increased nitrogenase activity without a lag period to 8.5 mg N/(kg h) . Investigation of the effect of environmental factors (temperature, pH, aeration, and light intensity) on potential nitrogen-fixing activity in peat samples revealed that nitrogen fixation could proceed in a wide range of pH values (from 3.0 to 7.5) and temperatures (from 5 to 35 degrees C) . The nitrogen-fixing bacteria belonging to different trophic groups were enumerated by using nitrogen-free media with pH values and mineralization levels close to those in situ . In samples of peat soil, diazotrophic methanol-utilizing bacteria prevailed (2.0-2.5 x 10(6) cells/g); the second largest group was facultatively anaerobic bacteria of the family Enterobacteriaceae.

J Antimicrob Chemother, 2003 May, 51(5), 1213 - 22 Epub 2003 Apr 14.
Frequency of isolation and antimicrobial susceptibility of bacterial pathogens isolated from patients with bloodstream infections: a French prospective national survey; Decousser JW et al.; All bloodstream strains, total 1463, isolated during a 1 month period in 105 hospitals representing all geographical areas in France were collected to study their antimicrobial susceptibility . The three major species were Escherichia coli, Staphylococcus aureus and coagulase-negative staphylococci . Among the 242 S . aureus, 87 were resistant to methicillin and among those 99% were resistant to ciprofloxacin, 11.5% to gentamicin, 1% to quinupristin/dalfopristin and 8% were heterogeneously resistant to vancomycin . Study of the methicillin-resistant S . aureus indicated that 12 clones had disseminated in French hospitals, six being heterogeneously resistant to vancomycin . Among the Streptococcus pneumoniae, 43% showed decreased susceptibility to the penicillins and 42% to erythromycin . One isolate was highly resistant to fluoroquinolones . Gentamicin, cefotaxime, ciprofloxacin and gatifloxacin resistance was rare in Enterobacteriaceae with 95% of strains susceptible . The incidence of extended-spectrum beta-lactamases was quite low . Moreover more than 25% of Pseudomonas aeruginosa strains were resistant to ciprofloxacin and gentamicin . The magnitude of antibiotic resistance in bloodstream isolates, in particular Gram-positive bacteria, emphasizes the importance of hospital control measures, rational prescribing policies and new vaccine strategies.

J Antimicrob Chemother, 2003 May, 51(5), 1141 - 51 Epub 2003 Apr 14.
Factors influencing gene expression and resistance for Gram-negative organisms expressing plasmid-encoded ampC genes of Enterobacter origin; Reisbig MD et al.; High-level expression of AmpC beta-lactamases results in organisms resistant to multiple beta-lactam antibiotics . The mechanism of chromosomally mediated AmpC resistance has been elucidated, however the mechanism(s) driving plasmid-encoded AmpC resistance are unknown . Studies were designed to identify factors which influence expression of plasmid-encoded ampC genes and correlate these factors with resistance . As the model system, ampC genes of Enterobacter origin were used to determine how gene copy number, genetic background and genetic organization influenced resistance phenotypes . To this end, gene expression from the plasmid-encoded inducible blaACT-1 and non-inducible blaMIR-1 were compared with chromosomal ampC gene expression from both wild-type (WT) and derepressed Enterobacter cloacae isolates . RNA levels within the original clinical isolates were examined using primer extension analysis, whereas a new PCR strategy was developed to examine gene copy number . These data revealed that blaACT-1 and blaMIR-1 constitutive expression was 33- and 95-fold higher than WT expression, whereas copy numbers of the plasmid-encoded genes were 2 and 12, respectively . Differences in promoters and transcriptional starts for the respective plasmid-encoded genes were noted and contribute to increases observed in overall expression . Finally, beta-lactam MICs were increased two- to 16-fold when blaACT-1 was expressed in Escherichia coli AmpD- strains compared with E . coli AmpD+ strains . In conclusion, high-level expression of plasmid-encoded ampC genes requires interplay between multiple factors including genetic organization, promoter modifications, genetic background, and to some extent gene copy number . In addition, clinical laboratories need to be aware that genetic backgrounds of inducible plasmid-encoded genes can dramatically influence MICs for organisms not normally associated with derepressed phenotypes.

J Antimicrob Chemother, 2003 May, 51(5), 1253 - 60 Epub 2003 Apr 14.
Efficacy of ertapenem in the treatment of serious infections caused by Enterobacteriaceae: analysis of pooled clinical trial data; Gesser RM et al.; OBJECTIVE: The efficacy of ertapenem, 1 g once a day, for treatment of adults with serious infections caused by Enterobacteriaceae was compared with ceftriaxone 1 g once a day {complicated urinary tract infection (CUTI) and community-acquired pneumonia (CAP)} or piperacillin-tazobactam, 3.375 g every 6 h (complicated intra-abdominal, complicated skin/skin structure and acute pelvic infections) . PATIENTS AND METHODS: This combined analysis included the subgroup of all 1167 treated patients infected with Enterobacteriaceae from seven randomized double-blind studies . RESULTS: Escherichia coli was the most common pathogen, accounting for 65.3% of all Enterobacteriaceae . Among evaluable patients with deep tissue (intra-abdominal, skin and pelvic) infections, the combined clinical cure rates were 84.8% (223 of 263) for ertapenem and 82.9% (194 of 234) for piperacillin-tazobactam {95% confidence interval (CI) for the difference, adjusting for infection, -4.9% to 8.9%} . Cure rates by infection for ertapenem and piperacillin-tazobactam, respectively, were: intra-abdominal, 85.1% (143 of 168) and 79.9% (119 of 149); pelvic, 86.8% (46 of 53) and 94% (47 of 50); skin/skin structure, 81% (34 of 42) and 80% (28 of 35) . Among patients with CUTI, microbiological cure rates were 90.5% (220 of 243) for ertapenem and 92% (196 of 213) for ceftriaxone (95% CI for the difference, -7.1% to 4.1%) . In patients with CAP, clinical cure rates were 95% (19 of 20) for ertapenem and 88.9% (16 of 18) for ceftriaxone . CONCLUSION: Ertapenem therapy was as effective as either piperacillin-tazobactam or ceftriaxone for serious infections caused by Enterobacteriaceae.

Int J Pediatr Otorhinolaryngol, 2003 May, 67(5), 447 - 51
Microbiology and management of acute suppurative thyroiditis in children; Brook I; This review describes the microbiology, diagnosis and management of suppurative thyroiditis (ST) . Staphylococcus aureus, Streptococcus pyogenes, Streptococcus epidermidis, and Streptococcus pneumoniae, are the predominant aerobic isolates . The most common anaerobic bacteria are Gram-negative bacilli and Peptostreptococcus spp . Agents that are rarely recovered include Klebsiella spp., Haemophilus influenzae, Streptococcus viridans, Salmonella spp., Enterobacteriaceae, Mycobacterium tuberculosis, atypical mycobacteria, Aspergillus spp., Coccidioides immitis, Candida spp., Treponema pallidum, and Echinococcus spp . Viruses have been associated with subacute thyroiditis, and include measles, mumps, influenza, enterovirus Epstein-barr, adenovirus, echovirus, and St Louis encephalitis . Therapy includes administration of antibiotics effective against the causative pathogen(s) . Proper selection of therapy can be guided by culture of the lesion . Surgical drainage may be necessary in case of suppuration.

Proteins, 2003 May 15, 51(3), 442 - 52
Role of beta-lactam carboxyl group on binding of penicillins and cephalosporins to class C beta-lactamases; Fenollar-Ferrer C et al.; Molecular models for the Henry Michaelis complexes of Enterobacter cloacae, a class C beta-lactamase, with penicillin G and cephalotin have been constructed by using molecular mechanic calculations, based on the AMBER force field, to examine the molecular differentiation mechanisms between cephalosporins and penicillins in beta-lactamases . Ser318Ala and Thr316Ala mutations in both complexes and Asn346Ala and Thr316Ala/Asn346Ala double mutation in penicillin G complex have also been studied . Results confirm that Thr316, Ser318, and Asn346 play a crucial role in the substrate recognition, via their interactions with one of the oxygens of the antibiotic carboxyl group . Both mutation Ser318Ala and Thr316Ala strongly affect the correct binding of cephalotin to P99, the first mainly by precluding the discriminating salt bridge between carboxyl and serine OH groups, and the second one by the Ser318, Lys315, and Tyr150 spatial rearrangements . On the other hand, Ser318Ala mutation has little effect on penicillin G binding, but the Thr316Ala/Asn346Ala double mutation causes the departure of the antibiotic from the oxyanion hole . Molecular dynamic simulations allow us to interpret the experimental results of some class C and A beta-lactamases .

FEMS Microbiol Lett, 2003 Apr 11, 221(1), 59 - 62
Direct sequencing and PCR mapping of integrons reveals multiple class 1 integrons in the multiresistant strain Enterobacter cloacae SCH88040794; Plante I et al.; We have characterized the variable region of three integrons found in the multiresistant strain Enterobacter cloacae SCH88040794, using polymerase chain reaction and direct sequencing of amplicons . The first integron has the gene cassette arrangement dfrAI-aadA1 in its variable region and the second aadB-oxa9 . The third integron is In40 (aacA4-qacF-cmlB-oxa9), which has recently been described . The multiresistance expressed by this strain to amikacin, gentamicin, trimethoprim, sulfonamides, oxacillin, chloramphenicol and quaternary ammonium compounds is due, at least in part, to these three integrons.

Biochem J . 2003 Apr 15; Pt {Epub ahead of print}
Relationship between bacterial virulence and nucleotide metabolism: a mutation in the adenylate kinase gene renders Yersinia pestis avirulent; Munier-Lehmann H et al.; Nucleoside monophosphate kinases (NMPKs) are essential catalysts for bacterial growth and multiplication . These enzymes display high primary sequence idendities among members of the family Enterobacteriaceae . Yersinia pestis, the causative agent of plague, belongs to this family . However, it was previously shown that its thymidylate kinase (TMPKyp) exhibits biochemical properties significantly different from those of its Escherichia coli counterpart {Chenal-Francisque et al . (1999) Eur . J . Biochem . 265, 112-119} . In this work, the adenylate kinase (AK) of Y . pestis (AKyp) was characterized . As for TMPKyp, AKyp displayed a lower thermodynamic stability than other studied AKs . Two mutations in AK (S129F and P87S), previously shown to induce a thermosensitive growth defect in E . coli, were introduced into AKyp . The recombinant variants had a lower stability than wild-type AKyp and a higher susceptibility to proteolytic digestion . When the P87S substitution was introduced into the chromosomal adk gene of Y . pestis, growth of the mutant strain was altered at the non-permissive temperature of 37 degrees C . In virulence testings, while less than 50 CFU of wild-type Y . pestis killed 100% of the mice upon subcutaneous infection, bacterial loads as high as 1.5 x 104 CFU of the adk mutant were unable to kill any animal.

Am J Vet Res, 2003 Apr, 64(4), 435 - 42
Characterization of the diversity of Haemophilus parasuis field isolates by use of serotyping and genotyping; Oliveira S et al.; OBJECTIVE: To characterize the genetic diversity of Haemophilus parasuis field isolates with regard to serovar, herd of origin, and site of isolation . SAMPLE POPULATION: Isolates of H parasuis obtained from pigs in 15 North American herds and multi-farm systems . PROCEDURE: 98 H parasuis isolates were genotyped with the enterobacterial repetitive intergeneic consensus based-polymerase chain reaction (ERIC-PCR) technique and serotyped via agar gel precipitation test . Genomic fingerprints were analyzed and dendrograms were constructed to identify strains from the same serovar group, herd of origin, or isolation site and to evaluate the genetic variability within these categories . RESULTS: Serovar 4 (39%) and nontypeable (NT) isolates (27%) were most prevalent . Thirty-four distinct strains were identified among the 98 isolates, using a 90% similarity cutoff . Strains from serovar 4 and NT isolates had high genetic diversity (12 and 18 strains, respectively) . One to 3 major clusters of prevalent strains could be identified in most of the evaluated herds . Haemophilus parasuis strains isolated from the upper respiratory tract were either serovar 3 or NT isolates . Potentially virulent strains (isolated from systemic sites) were either serovars 1, 2, 4, 5, 12, 13, or 14, or NT isolates . CONCLUSIONS AND CLINICAL RELEVANCE: Although H parasuis had high genetic diversity overall, only a few strains caused disease in these herds . The ERIC-PCR technique was more discriminative than serotyping, and a broad genetic variety was observed within particular serovar groups.

Niger Postgrad Med J, 2002 Dec, 9(4), 210 - 3
Beta-lactamase detection in nosocomial bacterial pathogens in Lagos, Nigeria; Kesah CN et al.; Beta-lactamase production was investigated in 1033 bacterial pathogens--262 gram-positive bacteria, 482 Enterobacteriaceae, 289 non-fermenting bacilli . These were isolated from nosocomial infections in paediatric patients . Beta-lactamase was detected using chromogenic cephalosporin and starch paper methods . More than 80% of the isolates produced the enzyme, which was not detected in enterococci and streptococci . There was no appreciable difference ({symbol: see text} 2 = 5.31, P > 0.05) in the number of Beta-lactamase producers obtained using the two methods . Great caution must be exercised in the therapeutic use of Beta-lactam drugs for nosocomial bacterial infections.

J Clin Microbiol, 2003 Apr, 41(4), 1740 - 2
Enterobacterial repetitive intergenic consensus 1R PCR assay for detection of Raoultella sp . isolates among strains identified as Klebsiella oxytoca in the clinical laboratory; Granier SA et al.; The enterobacterial repetitive intergenic consensus 1R PCR method, which provided recognizable profiles for reference strains of the three species of Raoultella and the two genetic groups of Klebsiella oxytoca, was applied to 19 clinical isolates identified as K . oxytoca . By this method, as confirmed by species-specific gene sequencing, two Raoultella ornithinolytica and two unclassifiable K . oxytoca isolates were identified.

J Clin Microbiol, 2003 Apr, 41(4), 1738 - 9
Isolation from blood culture of a Leclercia adecarboxylata strain producing an SHV-12 extended-spectrum beta-lactamase; Mazzariol A et al.; We report on the first isolation of an extended-spectrum beta-lactamase-producing Leclercia adecarboxylata strain from the bloodstream in a 58-year-old man with acute myeloid leukemia . The strain, resistant to ceftazidime, cefotaxime, and aztreonam, produces the SHV-12 beta-lactamase, one of the most common variants found in Italian nosocomial isolates of Enterobacteriaceae.

Pharmacotherapy, 2003 Apr, 23(4), 537 - 42
Enterobacter cloacae ventriculitis successfully treated with cefepime and gentamicin: case report and review of the literature; Barnes BJ et al.; A 55-year-old woman was found unresponsive and subsequently was diagnosed with a subarachnoid hemorrhage secondary to a right posterior communicating artery aneurysm . The development of hydrocephalus and decreased mental status necessitated placement of an intraventricular catheter; 18 days later she was diagnosed with Enterobacter cloacae ventriculitis . After treatment was begun with intravenous cefepime 2 g every 8 hours and intraventricular gentamicin 5 mg every 24 hours, the catheter was replaced . Cerebrospinal fluid (CSF) and plasma cefepime concentrations and a CSF trough gentamicin concentration were obtained . Intraventricular gentamicin was administered for 6 days and cefepime for 21 days; both clinical and microbiologic resolution of the ventriculitis occurred . The literature reports limited clinical experience with cefepime for the treatment of central nervous system infections in humans . This case report provides clinical evidence to support administration of intravenous cefepime in critically ill adult patients with Enterobacter ventriculitis . Because CSF is easily obtained from patients with intraventricular catheters, strong consideration should be given to monitoring CSF cefepime concentrations in concert with the minimum inhibitory concentration of the offending pathogen to help assure the efficacy of this approach to therapy.

Eur J Clin Microbiol Infect Dis, 2003 Apr, 22(4), 203 - 21 Epub 2003 Apr 01.
In vitro antibacterial activity and pharmacodynamics of new quinolones; Dalhoff A et al.; This synopsis of published literature summarises data on the in vitro antibacterial activity and pharmacodynamics of fluoroquinolones . Data were compiled for ciprofloxacin, levofloxcin, moxifloxacin, gatifloxacin, grepafloxacin, gemifloxacin, trovafloxacin, sitafloxacin and garenoxacin . All of these quinolones are almost equipotent against gram-negative bacteria but demonstrate improved activity against gram-positive species . The new quinolones are uniformly active against gram-positive species except Streptococcus pneumoniae; against which gemifloxacin, sitafloxacin and garenoxacin are one to two dilution steps more active than moxifloxacin . All of the new quinolones except gemifloxacin demonstrate enhanced activity against anaerobes . Since all the new quinolones show similar activity against the major respiratory tract pathogens except Streptococcus pneumoniae and members of the family Enterobacteriaceae, their pharmacokinetics and pharmacodynamics will be clinically relevant differentiators and determinants of their overall activity and efficacy . In vitro simulations of serum concentrations revealed that (i) . gemifloxacin and levofloxacin were significantly and gatifloxacin moderately less active than moxifloxacin against Streptococcus pneumoniae and Staphylococcus aureus, and (ii) . resistant subpopulations emerged following exposure to levofloxacin and gatifloxacin (gemifloxacin not yet published) but not to moxifloxacin . The emergence of resistance is a function of drug concentrations achievable in vivo and the susceptibility pattern of the target organisms . Therefore, the use of less potent fluoroquinolones with borderline or even suboptimal pharmacokinetic/pharmacodynamic surrogate parameters will inadvertently foster the development of class resistance . Drugs with the most favourable pharmacokinetic/pharmacodynamic characteristics should be used as first-line agents in order to preserve the potential of this drug class and, most importantly, to provide the patient with an optimally effective regimen.

Chest, 2003 Apr, 123(4), 1208 - 13
Evaluation of outcome in critically ill patients with nosocomial enterobacter bacteremia: results of a matched cohort study; Blot SI et al.; STUDY OBJECTIVE: To evaluate the clinical impact of nosocomial Enterobacter bacteremia in critically ill patients . DESIGN: Retrospective (January 1992 to December 2000) matched cohort study . SETTING: Fifty-four-bed ICU (including medical, surgical, cardiosurgical ICU, and burns unit) from a university hospital . PATIENTS: Sixty-seven ICU patients with Enterobacter bacteremia (case patients) and 134 control patients . INTERVENTION: Matching of control patients (1:2 ratio) was on the basis of the APACHE (acute physiology and chronic health evaluation) II system . As expected, mortality can be derived from this severity-of-disease classification system; this matching procedure results in an equal expected mortality rate for patients with Enterobacter bacteremia and control patients . RESULTS: The overall rate of appropriate antibiotic therapy in patients with Enterobacter bacteremia was high (96%) and initiated soon after the onset of the bacteremia (0.5 +/- 0.9 days) . Patients with Enterobacter bacteremia had more hemodynamic instability (p = 0.015), longer ICU stay (p < 0.001), and ventilator dependence (p < 0.001) . No differences between case and control patients were found in age (52 years vs 53 years, p = 0.831), prevalence of acute renal failure (16% vs 16%, p = 0.892), and acute respiratory failure (93% vs 84%, respectively; p = 0.079) . In-hospital mortality rates for case and control patients were not different (34% vs 39%, respectively; p = 0.536) . CONCLUSION: After accurate adjustment for severity of underlying disease and acute illness, no difference was found between ICU patients with Enterobacter bacteremia and matched control patients . In the presence of fast and appropriate antibiotic therapy, Enterobacter bacteremia does not adversely affect the outcome in ICU patients.

Lancet Infect Dis, 2003 Apr, 3(4), 201 - 13
Effects of intrapartum antimicrobial prophylaxis for prevention of group-B-streptococcal disease on the incidence and ecology of early-onset neonatal sepsis; Moore MR et al.; Sepsis occurring in the first week of life can be a devastating neonatal problem . Group B streptococci (GBS) and enterobacteriaceae are the main causes of early-onset sepsis in more developed countries . Intrapartum antimicrobial prophylaxis (IAP) has lowered the incidence of early-onset GBS sepsis by 50-80% . However, there are concerns that the use of IAP may select for infections caused by enterobacteriaceae, including some strains resistant to antimicrobials . We explored potential associations between IAP use and changes in the causes of early-onset sepsis . We concluded that there have been substantial declines in the incidence of early-onset infections due to GBS and, in some settings, other bacteria . Increases in the frequencies of non-GBS or antimicrobial-resistant early-onset sepsis have been limited to preterm, low-birthweight, or very-low-birthweight neonates . We propose systematic monitoring of early-onset sepsis, coupled with targeted research, to inform periodic reassessment of prevention strategies.

J Med Microbiol, 2003 Apr, 52(Pt 4), 289 - 94
Expression of heterologous O-antigen in Yersinia pestis KIM does not affect virulence by the intravenous route; Oyston PC et al.; All strains of Yersinia pestis examined have been found to lack an O-antigen . In other members of the Enterobacteriaceae, the rough phenotype often results in attenuation . However, Y . pestis is the aetiological agent of bubonic plague . In evolving from the ancestral enteropathogenic Yersinia pseudotuberculosis, and with the development of an arthropod-vectored systemic pathogenesis, smooth LPS production is not necessary for Y . pestis virulence and the metabolic burden has been alleviated by inactivation of the O-antigen biosynthetic operon . To investigate this, Y . pestis strain KIM D27 was transformed with a plasmid carrying the operon encoding the O-antigen of Yersinia enterocolitica O : 3 . Expression of the O-antigen could be detected in silver-stained gels . The receptor for bacteriophage phiYeO3-12 has been shown to be O-antigen, and infection by this bacteriophage results in lysis of Y . enterocolitica O : 3 . Expression of the O-antigen in Y . pestis conferred sensitivity to lysis by phiYeO3-12 . The O-antigen-expressing clone was shown to be as virulent in mice by the intravenous route of challenge as the rough wild-type . Assays showed no alteration in the ability of Y . pestis to resist lysis by cationic antimicrobial peptides, serum or polymyxin.

Appl Environ Microbiol, 2003 Apr, 69(4), 2389 - 94
Molecular characterization of Vibrio cholerae O139 bengal isolated from water and the aquatic plant Eichhornia crassipes in the River Ganga, Varanasi, India; Bhanumathi R et al.; A collection of ten strains of Vibrio cholerae O139, comprising six isolates from Eichhornia crassipes, two from water of the River Ganga, and one each from a well and a hand pump, were characterized . All the strains carried the CTX genetic element (ctxA, zot, and ace) except for the st gene and carried structural and regulatory genes for toxin-coregulated pilus (tcpA, tcpI, and toxR), adherence factor (ompU), and accessory colonization factor (acfB); all produced cholera toxin (CT) . These strains were resistant to trimethoprim, sulfamethoxazole, streptomycin, and to the vibriostatic agent pteridine . Results obtained by ribotyping and enterobacterial repetitive intergenic consensus sequence-PCR fingerprint analysis indicate that multiple clones of toxigenic-pathogenic V . cholerae O139 were present in the aquatic environment.

Mol Microbiol, 2003 Apr, 48(2), 443 - 52
Turnover of FlhD and FlhC, master regulator proteins for Salmonella flagellum biogenesis, by the ATP-dependent ClpXP protease; Tomoyasu T et al.; In enterobacteria such as Salmonella, flagellar biogenesis is dependent upon the master operon flhDC at the apex of the flagellar gene hierarchy, which is divided into three classes 1, 2 and 3 . Previously we reported that depletion of the ClpXP ATP-dependent protease results in dramatic enhancement of class 2 and class 3 gene transcription, whereas the transcription level of the flhDC operon remains normal in Salmonella enterica serovar Typhimurium . This suggests that the ClpXP protease may be responsible for the turnover of the FlhD and FlhC master regulators (Tomoyasu, T., Ohkishi, T., Ukyo, Y., Tokumitsu, A., Takaya, A., Suzuki, M . et al., 2002, J Bacteriol 184:645-653) . In this study, to establish the role of the ClpXP protease in the turnover of FlhD and FlhC proteins, we analysed levels of the FlhD and FlhC proteins in wild-type and ClpXP mutant cells using anti-FlhD and anti-FlhC antibodies . The results show that both FlhD and FlhC proteins are markedly accumulated in ClpXP mutant cells and the half-life of FlhC is approximately fivefold longer in the ClpXP mutant, suggesting that the ClpXP protease is responsible for the degradation of FlhD and FlhC . The results also show that the ClpXP protease degrades both proteins in FlhD2FlhC2 complex but does not seem to recognize the respective subunits synthesized individually . Taken together, it is suggested that the cellular concentration of the FlhD2FlhC2 master regulator is tightly controlled at the post-translational level by the ClpXP protease . We also examined the role of other members of the ATP-dependent protease family in the regulation of flagellar biogenesis and concluded that only ClpXP in this family functions as a negative regulator for flagellar biogenesis in Salmonella.

J Bacteriol, 2003 Apr, 185(8), 2475 - 84
Molecular characterization of the acid-inducible asr gene of Escherichia coli and its role in acid stress response; Seputiene V et al.; Enterobacteria have developed numerous constitutive and inducible strategies to sense and adapt to an external acidity . These molecular responses require dozens of specific acid shock proteins (ASPs), as shown by genomic and proteomic analysis . Most of the ASPs remain poorly characterized, and their role in the acid response and survival is unknown . We recently identified an Escherichia coli gene, asr (acid shock RNA), encoding a protein of unknown function, which is strongly induced by high environmental acidity (pH < 5.0) . We show here that Asr is required for growth at moderate acidity (pH 4.5) as well as for the induction of acid tolerance at moderate acidity, as shown by its ability to survive subsequent transfer to extreme acidity (pH 2.0) . Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western analysis of acid-shocked E . coli cells harboring a plasmid-borne asr gene demonstrated that the Asr protein is synthesized as a precursor with an apparent molecular mass of 18 kDa . Mutational studies of the asr gene also demonstrated the Asr preprotein contains 102 amino acids . This protein is subjected to an N-terminal cleavage of the signal peptide and a second processing event, yielding 15- and 8-kDa products, respectively . Only the 8-kDa polypeptide was detected in acid-shocked cells containing only the chromosomal copy of the asr gene . N-terminal sequencing and site-directed mutagenesis revealed the two processing sites in the Asr protein precursor . Deletion of amino acids encompassing the processing site required for release of the 8-kDa protein resulted in an acid-sensitive phenotype similar to that observed for the asr null mutant, suggesting that the 8-kDa product plays an important role in the adaptation to acid shock . Analysis of Asr:PhoA fusions demonstrated a periplasmic location for the Asr protein after removal of the signal peptide . Homologues of the asr gene from other Enterobacteriaceae were cloned and shown to be induced in E . coli under acid shock conditions.

Clin Microbiol Infect, 2003 Mar, 9(3), 202 - 11
Lymphocyte subset numbers depend on the bacterial origin of sepsis; Holub M et al.; OBJECTIVE: To determine the quantitative variances in peripheral blood lymphocyte subsets during sepsis, and their clinical significance . METHODS: Peripheral blood lymphocyte subsets were enumerated in 32 non-surgical septic patients during the first 14 days of hospitalization; results from septic patients were compared with those from 34 healthy controls . Influences of the severity and the bacterial etiology of sepsis on changes in lymphocyte subsets were also assessed . RESULTS: Significant decreases (P < 0.05) from normal values of CD4+, CD8+ and total T-lymphocytes were observed in septic patients, but the decline persisted only for CD4+ T-lymphocytes and natural killer (NK) cells for 3 and 7 days, respectively . In addition, the numbers of CD3+/DR+ lymphocytes were significantly elevated on day 14 . There were no correlations between these alterations and the severity of sepsis . Gram-positive sepsis (n = 10), which was mainly due to Streptococcus pneumoniae and Staphylococcus aureus, caused prolonged decreases in CD4+, CD8+ and total T-lymphocytes, and a reduction in NK cells, that lasted for >or=14 days . Conversely, patients with sepsis due to Gram-negative pathogens (Neisseria meningitidis, n = 8; enterobacteria, n = 2) achieved full recovery of the subsets within 3 days . Moreover, the patients with Gram-negative sepsis demonstrated a significant increase in B-lymphocytes, and a rise in the numbers of CD3+/DR+ and CD4+ T-lymphocytes, which were more rapid than in patients with Gram-positive sepsis . CONCLUSION: Our results indicate that Gram-positive sepsis causes stronger suppression of peripheral blood lymphocyte subsets in comparison to sepsis due to Gram-negative pathogens.

J Biol Chem, 2003 Jun 6, 278(23), 20555 - 64 Epub 2003 Mar 27.
TLR4-dependent lipopolysaccharide-induced shedding of tumor necrosis factor receptors in mouse bone marrow granulocytes; Pedron T et al.; We reported previously that bone marrow granulocytes respond to small amounts of enterobacterial lipopolysaccharide (LPS) via a CD14-independent and TLR4-mediated mechanism by de novo expression of an inducible receptor (CD14) and by down-modulation of a constitutive receptor (L-selectin) . In this report we address another effect of LPS: the down-regulation of receptors for tumor necrosis factor-alpha . In mouse bone marrow cells (BMC), this down-regulation is detectable soon (20 min) after exposure of the cells to low levels (0.5 ng/ml) of LPS . This temperature-dependent effect is rather selective for LPS and requires the presence of a conventional lipid A structure in the LPS molecule and a functional TLR4 molecule in the cells . The down-modulation, due to a shedding of the receptors, is blocked by p38 MAPK inhibitors, by a furin inhibitor, and by three metalloproteinase inhibitors (BB-3103, TIMP-2, and TIMP-3) . In contrast, inhibitors of MEK, protein kinase C, cAMP-dependent protein kinase, and kinases of the Src family do not block the shedding . Analysis of BMC from mice lacking tumor necrosis factor receptor-1 (CD120a-/-) or tumor necrosis factor receptor-2 (CD120b-/-) indicates that the LPS-induced shedding is specific for CD120b . Thus, exposure of BMC to LPS triggers a rapid shedding of CD120b via a protein kinase C- and Src-independent pathway mediated by p38 MAPK, furin, and metalloproteinase . The additive effects of furin and metalloproteinase inhibitors suggest that these enzymes are involved in parallel shedding pathways.

Diagn Microbiol Infect Dis, 2003 Mar, 45(3), 173 - 81
One predominant type of genetically closely related Shigella sonnei prevalent in four sequential outbreaks in school children; Lee TM et al.; Seventy-six Shigella sonnei isolates from four sequential outbreaks in school children were analyzed to determine their relatedness . Outbreak strains exhibited two major antibiograms, 9 plasmid profiles, 10 enterobacterial repetitive intergenic consensus sequence (ERIC)-PCR patterns, and 17 pulsed-field gel electrophoresis (PFGE) patterns . Of typing methods, ERIC-PCR types generally coincided with the PFGE types within these outbreak strains . However, ERIC-PCR analysis could not discriminate an epidemiologically unrelated strain from some outbreak strains . Further computer-assisted analysis for similarity of the PFGE patterns revealed that the main culprits of these four sequential outbreaks were strains of pulsotype C (88.2% of total outbreak isolates) . The results indicate that PFGE can provide more explicit relatedness of outbreak strains than the other typing methods examined . In conclusion, based on PFGE analysis, one predominant pulsotype of multiple genetically related strains of S . sonnei was prevalent in these four sequential outbreaks.

Environ Microbiol, 2003 Apr, 5(4), 238 - 49
Use of a site-specific recombination-based biosensor for detecting bioavailable toluene and related compounds on roots; Casavant NC et al.; We constructed and characterized a plasmid-based genetic system that reports the expression of a toluene-responsive promoter (PtbuA1) by effecting an irreversible, heritable change in the biosensor cell . Expression of the reporter gene gfp is strongly repressed in the absence of expression from the PtbuA1 promoter, and high level gfp expression in the original cell and its progeny is mediated by the site-specific recombination machinery of bacteriophage P22 to initiate removal of a repressor cassette . The reporter plasmid pTolLHB was functional in two soil saprophytes, Pseudomonas fluorescens A506 and Enterobacter cloacae JL1157, with the efficiency and sensitivity to low toluene concentrations being optimal in P . fluorescens A506 . In culture, 80-100% of the A506 (pTolLHB) population expressed gfp following exposure to 0.2 micro m toluene for one to three hours . Compared to the response of A506 containing a plasmid-borne PtbuA1-gfp fusion, the recombination-based biosensor was more sensitive at detecting low toluene and trichloroethylene concentrations . An A506 (pTolLHB) inoculum, which had a background of 2.5% of the cells expressing gfp, was introduced onto barley roots in soil microcosms . If toluene was introduced into the microcosms, after 24 h, 72% of the A506 (pTolLHB) cells recovered from roots expressed gfp, indicating bioavailable toluene to rhizosphere bacteria . When toluene was not introduced, 16.5% of the A506 (pTolLHB) cells recovered from the roots expressed gfp, indicating that natural inducers of the PtbuA1 promoter were present in the barley rhizosphere . When introduced into rhizotrons containing barley plants and toluene vapours, the biosensor allowed localization of the availability of toluene along the seminal roots . In rhizotrons that were not exposed to toluene vapours, the biosensor exhibited high PtbuA1-promoter activity in distinct regions along the seminal roots, indicating spatial heterogeneity plant- or rhizosphere microbial community-derived inducers of the PtbuA1 promoter . This recombination-based toluene biosensor thus was useful in identifying bacterial exposure to transient or low levels of toluene, or related compounds, directly in the environment.

J Hosp Infect, 2003 Apr, 53(4), 292 - 6
Nosocomial outbreak of Enterobacter gergoviae bacteraemia in a neonatal intensive care unit; Ganeswire R et al.; A nosocomial outbreak of bacteraemia, caused by Enterobacter gergoviae infected 11 babies, nine of whom were premature, and was investigated in the neonatal intensive care unit (NICU) of a general hospital in Johor Bahru, Malaysia . The strain that was isolated from the babies was also isolated from the dextrose saline used for the dilution of parenteral antibiotics and from the hands of a healthcare worker on duty in the nursery . Pulsed-field gel electrophoresis (PFGE) of Xba I-digested chromosomal DNA confirmed a possible cross-contamination of parenteral dextrose saline and the healthcare worker . Prompt and effective control measures were initiated within NICU and the nosocomial infection of E . gergoviae was brought to an abrupt end . To the best of our knowledge, this is the first documented outbreak of E . gergoviae in the NICU in a hospital in the state of Johor, Malaysia.

Mol Microbiol, 2003 Apr, 48(1), 157 - 71
Phase variation of the 987P-like CS18 fimbriae of human enterotoxigenic Escherichia coli is regulated by site-specific recombinases; Honarvar S et al.; The gene cluster of the CS18 (PCFO20) fimbriae of human enterotoxigenic Escherichia coli (ETEC) was found to include seven genes (fotA to fotG) that are similar to each of the seven structural and export proteins of the 987P fimbriae . However, no analogous gene to the fasH regulatory gene, which is located at the 3' end of the 987P gene cluster and encodes an AraC-like activator of transcription, could be detected . Surprisingly, two novel genes (fotS and fotT) encoding proteins similar to the site-specific recombinases of the type 1 fimbriae (FimB and FimE) were identified at the 5' end of the fot gene cluster . These genes were shown to be required for the catalysis of a 312 bp-inversion just upstream of fotA . The inversion determines CS18 fimbrial phase variation . FotS participates in inverting the 312 bp-segment in both the ON and OFF orientation, whereas FotT has a bias for the OFF oriented recombination . Similar regulators of fimbriation by phase variation were described in uropathogenic and commensal Enterobacteriaceae . In contrast, only AraC-like transcriptional activators were previously described as regulators of the intestinal colonization factors of human ETEC isolates . Thus, the CS18 and 987P gene clusters encode similar components for fimbrial biogenesis but different types of regulators for fimbriation . The combination of blocks of genes encoding similar structural products but different regulatory proteins underlines how modular DNA rearrangements can evolve by serving pathogen diversification . Acquisition of a phase variation module to regulate fimbrial genes is proposed to be beneficial for the adaptation and transmission of pathogens.

Rev Gastroenterol Mex, 2002 Oct-Dec, 67(4), 267 - 70
{Extracolonic manifestation as first sign of colorectal carcinoma . Report of 2 cases}; Hinojosa CA et al.; INTRODUCTION: In Mexico, colorectal cancer is the second most common malignant tumor of digestive tract; incidence is proportional to patient age . At time of diagnosis, 20% of patients can be found with metastases, liver and lung the organs affected most frequently . OBJECTIVE: To present two young patients, whose primary complaints were atypical extracolonic symptoms of colorectal cancer . CASE DESCRIPTION: CASE 1: A 44-year-old female who presented with left pleural effusion, with growth in culture positive for enterobacterias . Barium enema showed tumor in splenic flexure . Surgical resection was performed including, left kidney, spleen, tail of pancreas, and fourth portion of duodenum . Colo-pleural fistula was repaired with primary closure . The pathology report noted locally advanced adenocarcinoma of colon (T4 N0 M0) . CASE 2: A 22-year-old female, who presented with a 30 day history of neurologic complaints . Computer tomography of head and MRI of brain identified a mass at level of cerebellum; specimen biopsy report was consistent with metastasis adenocarcinoma . Colonoscopy found a tumor located 12 cm from anal verge . The patient underwent sigmoid resection . Pathology confirmed the presence of moderately differentiated adenocarcinoma and 14/22 positive nodes (T3, N2, M1) . CONCLUSION: The most common sites of metastases secondary to colorectal cancer are liver and lung, up to 30% at diagnosis, and usually are asymptomatic . We reported two patients whose first evidence of disease were atypical symptoms related to unusual sites of colorectal cancer extension.

J Chromatogr B Analyt Technol Biomed Life Sci, 2003 Mar 25, 786(1-2), 197 - 205
Overexpression and purification of the three components of the Enterobacter aerogenes AcrA-AcrB-TolC multidrug efflux pump; Masi M et al.; The tripartite AcrA-AcrB-TolC system is the major efflux pump of the nosocomial pathogen Enterobacter aerogenes . AcrA is a trimeric periplasmic lipoprotein anchored in the inner membrane, AcrB is an inner membrane transporter and TolC is a trimeric outer membrane channel . In order to reconstitute the AcrA-AcrB-TolC system of E . aerogenes in artificial membranes, we overexpressed and purified the three proteins . The E . aerogenes acrA, acrB and tolC open reading frames were individually inserted in the expression vector pET24a(+), in frame with a sequence coding a C-terminal hexahistidine tag to allow purification by INAC (Immobilized Nickel Affinity Chromatography) . The mature AcrA-6His was overproduced in a soluble form in the cytoplasm of Escherichia coli BL21(DE3) . AcrA-6His was purified under native conditions in two steps using INAC and gel permeation chromatography . We obtained about 25 mg of 97% pure AcrA-6His per liter of culture . AcrB-6His was solubilized from the membrane fraction of E . coli C43(DE3) in 300 mM NaCl, 5% Triton X-100 and purified in one step by INAC . The AcrB-6His enriched fraction was eluted with 100 mM imidazole . The final yield was 1-2 mg of 95% pure AcrB-6His per liter of culture . The membrane fraction of E . coli BL21(DE3)pLysS containing TolC-6His was first treated with 2% Triton X-100, 30 mM MgCl(2) to solubilize the inner membrane proteins . After ultracentrifugation, the pellet was treated with 5% Triton X-100, 5 mM EDTA to solubilize the outer membrane proteins . Approximately 5 mg of 95% pure TolC-6His trimers per liter of culture was purified by INAC.

Dtsch Med Wochenschr, 2003 Mar 21, 128(12), 607 - 10
{Human cowpox/catpox infection . A potentially unrecognized disease}; Steinborn A et al.; HISTORY AND ADMISSION FINDINGS: A 36-year-old woman initially noticed a red spot, about pea-sized, with a central pimple over the right eyebrow and a swollen submandibular lymph node . A pressure-sensitive, 4 cm large, node developed out of this small spot, with a central, black, tightly-adhering crust bearing several varioliform vesicles around its edge . In addition to swelling of the right half of the face, the patient had a fever up to 39.5 degrees C, general malaise, nausea and vomiting . Various antibiotics were ineffective . The woman was hospitalized with a diagnosis of facial erysipelas . She owned a cat which had developed a purulent nodule on a forepaw a few days before onset of the patient's disease . LABORATORY TEST: ESR and CRP were moderately elevated, no leukocytosis and blood cultures were sterile . Wound smears showed colonization with Klebsiella pneumoniae and Enterobacter cloacae . DIAGNOSIS, TREATMENT AND COURSE: The patient's general condition improved under initially calculated antibiotic dosages, which was later adapted to the measured resistance . The black-crusted nodes became larger, however, and incision was performed on the 8 th day after hospitalization, under the suspicion of fluctuation . However, no pus was removed, but there was massive inflammatory infiltration of the soft tissue . Examination of samples of skin and part of the crust revealed orthopox virus (cowpox virus) . Spontaneous healing followed within 3 weeks, leaving only a small scar . CONCLUSIONS: This was a cowpox virus in the sense of a zoonosis transmitted by the cat . In Germany, now that smallpox has been eradicated, the clinical presentation of infections with the orthopox virus, which are closely related to variola virus, are too little recognized . Atopic and immunocompromised patients are at risk of a cutaneous dissemination with a more severe course of the infectious illness; even a lethal outcome has been reported in Germany.

Trends Microbiol, 2003 Mar, 11(3), 115 - 7
Enterobacterial adhesins and the case for studying SNPs in bacteria; Weissman SJ et al.; Single-nucleotide polymorphisms (SNPs) in structural genes can have a dramatic effect on the biology of whole organisms, from bacteria and viruses to mammals . Here, we underscore the importance of SNPs in bacterial genes that contribute to the ability of pathogens to cause disease . SNPs that confer an adaptive advantage for bacterial pathogens have been discovered in the genes encoding the FimH and Dr adhesins of Escherichia coli and, most recently, Salmonella enterica sv . Typhimurium FimH.

Res Microbiol, 2003 Mar, 154(2), 105 - 14
Fluctuation of bacteria isolated from elm tissues during different seasons and from different plant organs; Mocali S et al.; In this work we isolated a culturable endophytic aerobic heterotrophic bacterial community from the stem and root tissues of elm trees (Ulmus spp.) and analyzed its fluctuations . A total of 724 bacterial isolates were collected at different times (April, June, September and December) from two elm trees, one infected with Elm Yellows phytoplasmas, and one which was healthy-looking . The isolates were grouped into 82 haplotypes, identified by means of amplified ribosomal DNA restriction analysis (ARDRA) using the restriction enzyme AluI, suggesting that the genetic diversity of the bacterial community was very high . The taxonomic position of the isolates belonging to the twelve main haplotypes, representing more than 72% of the total population, was determined by 16S rDNA sequencing . The main genera were Bacillus, Curtobacterium, Pseudomonas, Stenotrophomonas, Sphingomonas, Enterobacter, and Staphylococcus . The fluctuations in the bacterial community, determined by different parameters (seasonal changes, plant organ, presence of phytoplasmas) were studied, revealing that they were influenced both by variations in temperature (warm or cold according to the season) and by the organ examined (roots or stems) . The role of the phytopathogenic status in these fluctuations was also discussed.

J Food Prot, 2003 Mar, 66(3), 370 - 5
Enterobacter sakazakii: infectivity and enterotoxin production in vitro and in vivo; Pagotto FJ et al.; Enterobacter sakazakii has been implicated as the causal organism in a severe form of neonatal meningitis, with reported mortality rates of 40 to 80% . Dried infant formula has been identified as a potential source of the organism in both outbreaks and sporadic cases . In this study, clinical and foodborne isolates of E . sakazakii were evaluated for enterotoxin production by the suckling mouse assay . In addition, suckling mice were challenged both orally and by intraperitoneal injection . Of 18 E . sakazakii strains evaluated, four were found to test positive for enterotoxin production . All strains of E . sakazakii were lethal to suckling mice at 10(8) CFU per mouse by intraperitoneal injection, while two strains caused death by the peroral route . In in vitro assays, CHO, Vero, and Y-1 cells demonstrated both cell lysis and rounding when exposed to E . sakazakii strain LA filtrates . This is the first report describing any putative virulence factors of E . sakazakii.

J Food Prot, 2003 Mar, 66(3), 364 - 9
Molecular characterization of Arcobacter isolates collected in a poultry slaughterhouse; Houf K et al.; In a poultry slaughterhouse, Arcobacter contamination was examined over a period of 1 week to establish possible routes of contamination . Samples were collected from the slaughter equipment and from processing water before the onset of slaughter and from the first broiler flock slaughtered on each sampling day . Characterization of 1,079 isolates by enterobacterial repetitive intergenic consensus-polymerase chain reaction and a random amplified polymorphic DNA assay resulted in the delineation of 159 Arcobacter butzleri and 139 Arcobacter cryaerophilus types . From almost all 140 neck skin samples collected before and after evisceration, A . butzleri and A . cryaerophilus were isolated simultaneously at contamination levels ranging from 10(1) to 10(4) CFU/g . Only six A . butzleri types present in the slaughterhouse environment were also present on the broiler carcasses . None of the A . cryaerophilus genotypes were detected in both the neck skin and the environmental samples . All A . butzleri types isolated from the feather samples were also isolated from broiler neck skin samples . The slaughter equipment was contaminated with arcobacters before the onset of slaughter, but it appeared unlikely that contamination through the slaughter equipment alone explained the high contamination levels on poultry products . Arcobacters were also present in processing water, but types present in water and poultry products were different . Characterization of the Arcobacter isolates did not clarify the routes of transmission, probably because of the extreme heterogeneity among Arcobacter isolates . However, the results obtained in this study brought to light insufficient decontamination at the processing plant involved in the study and confirmed the survival capacity of certain A . butzleri strains.

Int J Med Microbiol, 2003 Feb, 292(7-8), 495 - 503
Sequencing of 16S rDNA of Klebsiella: taxonomic relations within the genus and to other Enterobacteriaceae; Boye K et al.; The 16S rDNAs of 20 strains of Klebsiella were sequenced and used for construction of a phylogenetic tree together with already published Enterobacteriaceae 16S rDNA sequences . The taxonomy within the Klebsiella genus, as reflected by the 16S rDNA tree, was in agreement with existing DNA-DNA hybridisation and numerical taxonomy data, indicating that for Klebsiella, 16S rDNA sequencing is a valid method for identification and taxonomical purposes . Five closely related clusters were found in the Klebsiella genus; Cluster I, K . oxytoca; Cluster II, K . terrigena, Cluster III, K . planticola and K . ornithinolytica; Cluster IV, Enterobacter aerogenes (K . mobilis); and Cluster V, K . pneumoniae . The position of Calymmatobacterium granulomatis within the genus and closest to K . pneumoniae was confirmed . For the species K . oxytoca, data seem to indicate a subdivision into two subspecies . In addition, a biochemically aberrant Klebsiella strain (BEC441) that was included in the analysis could not be assigned to any of the known species, but was found to be closest related to K . oxytoca . Furthermore, the high sequence similarity between the two environmental species K . planticola and K . ornithinolytica does not justify a distinction of the two species . Finally, within a 165-bp stretch of the 16S rDNA sequences, species-specific nucleotides were found.

Med Dosw Mikrobiol, 2002, 54(3), 199 - 213
{Microbiological External Quality Assurance Program (MEQAO)--evaluation of results obtained in 2001 of sanitary-epidemiological station laboratories}; Szych J et al.; The aim of this study was to evaluate reliability of identification and determination of sensitivity to antibiotics and chemotherapeutics of some Enterobacteriaceae strains in 49 sanitary-epidemiological stations . All laboratories engaged in this study received 4 strains each (S . marcescens phenotype ESBL+, K . pneumoniae phenotype ESBL+, S . Typhimurium and S . Newport) previously identified in the Department of Bacteriology of National Institute of Hygiene . The laboratories included in the survey were asked to determine the genus (serovar) of each control strain using the lowest number of biochemical test recommended by Institute and to determine of the sensitivity of the identified strains to antibiotics in accordance with the guidelines of the NCCLS and domestic recommendations . Only in 2 participating laboratories the identification of one of studied strains (K . pneumoniae) was completely bad and in 9 laboratories the serological identification of S . Newport was incomplete or serological type was not correctly recognised . In the determination of the sensitivity of the control strains to chemotherapeutic agents abnormalities were found in the technique of antibiogram and test for ESBL performing and incorrect selection of disc for antibiograms as well as erroneous interpretation of the results.

J Hosp Infect, 2003 Mar, 53(3), 177 - 82
Impact of a multidisciplinary approach to the control of antibiotic prescription in a general hospital; Saizy-Callaert S et al.; We examined the impact of a rational antibiotic prescription programme based on a multidisciplinary consultative approach in a 600-bed hospital . The programme involved four measures: (1) . drawing up of a local prescribing consensus with all prescribers; (2) . a restricted prescriptions policy for the most expensive antibiotics; (3.assessment of the prescription of these antibiotics by regular audits; and (4) . institutional training and information for prescribers . The impact of the programme was assessed by comparing actual prescriptions with the criteria of the local consensus, compliance with the restrictive prescription policy, changes in the average daily cost of antibiotic therapy per inpatient and changes in the local ecology of methicillin-resistant Staphylococcus aureus (MRSA), Enterobacteriaceae producing extended-spectrum beta-lactamases (EPESB) and ceftazidime-resistant Pseudomonas species (CRP) . Using a participatory consensual approach, 182 reference recommendations were established (104 for adults, 78 for children), corresponding to 85% of the clinical settings encountered in the hospital . Six audits, conducted since June 1997, show that the rate of unjustified prescriptions first fell significantly (from 6 to 0%, P<0.001), then increased significantly (from 0 to 3%, P<0.05) before stabilizing at 3% . The cost of antimicrobials per inpatient day fell significantly (from US dollars 13.8 in 1997 to US dollars 11 in 2000, P<0.001) . The prevalence of MRSA and CRP remained stable, while that of EPESB fell significantly (P<0.001) . This multidisciplinary consultative approach thus reduced antibiotic costs, contributed to infection control, and improved the quality of antibiotic prescription.

Jpn J Antibiot, 2002 Dec, 55(6), 855 - 60
{A questionnaire survey on antimicrobial chemotherapy for acute peritonitis}; Shinagawa N et al.; A questionnaire survey on antimicrobial chemotherapy for acute peritonitis was conducted to obtain the consensus among abdominal surgeons in Japan in the period from January to March 2002 . Forty-one of the 58 surgeons replied, and the following consensus was obtained . Antibiotics should be given as soon as possible the diagnosis of infection in the abdominal cavity is established . When the perforated viscus is demonstrated at operation, giving antibiotic should be reconfirmed whether it covers organisms in the perforated site or not . The ascites obtained at operation should be sent for bacterial culture . When postoperative course is eventful, considering WBC, body temperature and CRP, the drainage fluid should be sent for culture on 4 to 7 days postoperatively . Most commonly used antibiotic for perforation of duodenal ulcer is cefotiam, and it is given 4.1 +/- 1.2 days postoperatively . Target organisms at the perforation of the lower digestive tract were E . coli, Bacteroides spp., Klebsiella pneumoniae and Enterobacter spp . Carbapenems were likely given agents for the perforation of the colon, and they were given 5.0 +/- 1.4 days postoperatively.

J Biol Chem, 2003 May 9, 278(19), 16534 - 42 Epub 2003 Mar 05.
Evidence that the wzxE gene of Escherichia coli K-12 encodes a protein involved in the transbilayer movement of a trisaccharide-lipid intermediate in the assembly of enterobacterial common antigen; Rick PD et al.; The assembly of many bacterial cell surface polysaccharides requires the transbilayer movement of polyisoprenoid-linked saccharide intermediates across the cytoplasmic membrane . It is generally believed that transverse diffusion of glycolipid intermediates is mediated by integral membrane proteins called translocases or "flippases." The bacterial genes proposed to encode these translocases have been collectively designated wzx genes . The wzxE gene of Escherichia coli K-12 has been implicated in the transbilayer movement of Fuc4NAc-ManNAcA-GlcNAc-P-P-undecaprenol (lipid III), the donor of the trisaccharide repeat unit in the biosynthesis of enterobacterial common antigen (ECA) . Previous studies (Feldman, M . F., Marolda, C . L., Monteiro, M . A., Perry, M . B., Parodi, A . J., and Valvano, M . (1999) J . Biol . Chem . 274, 35129-35138) provided indirect evidence that the wzx(016) gene product of E . coli K-12 encoded a translocase capable of mediating the transbilayer movement of N-acetylglucosaminylpyrophosphorylundecaprenol (GlcNAc-P-P-Und), an early intermediate in the synthesis of ECA and many lipopolysaccharide O antigens . Therefore, genetic and biochemical studies were conducted to determine if the putative Wzx(O16) translocase was capable of mediating the transport of N-acetylglucosaminylpyrophosphorylnerol (GlcNAc-P-P-Ner), a water-soluble analogue of GlcNAc-P-P-Und . {(3)H}GlcNAc-P-P-Ner was transported into sealed, everted cytoplasmic membrane vesicles of E . coli K-12 as well as a deletion mutant lacking both the wzx(016) and wzxC genes . In contrast, {(3)H}GlcNAc-P-P-Ner was not transported into membrane vesicles prepared from a wzxE-null mutant, and metabolic radiolabeling experiments revealed the accumulation of lipid III in this mutant . The WzxE transport system exhibited substrate specificity by recognizing both a pyrophosphoryl-linked saccharide and an unsaturated alpha-isoprene unit in the carrier lipid . These results support the conclusion that the wzxE gene encodes a membrane protein involved in the transbilayer movement of lipid III in E . coli.

Appl Environ Microbiol, 2003 Mar, 69(3), 1435 - 41
Evaluation of genetic diversity among Pseudomonas citronellolis strains isolated from oily sludge-contaminated sites; Bhattacharya D et al.; The diversity among a set of bacterial strains that have the capacity to degrade total petroleum hydrocarbons (TPH) in soil contaminated with oily sludge (hazardous hydrocarbon waste from oil refineries) was determined . TPH is composed of alkane, aromatics, nitrogen-, sulfur-, and oxygen-containing compound, and asphaltene fractions of crude oil . The 150 bacterial isolates which could degrade TPH were isolated from soil samples obtained from diverse geoclimatic regions of India . All the isolates were biochemically characterized and identified with a Biolog microbial identification system and by 16S rDNA sequencing . Pseudomonas citronellolis predominated among the 150 isolates obtained from six different geographically diverse samplings . Of the isolates, 29 strains of P . citronellolis were selected for evaluating their genetic diversity . This was performed by molecular typing with repetitive sequence (Rep)-based PCR with primer sets ERIC (enterobacterial repetitive intergenic consensus), REP (repetitive extragenic palindromes), and BOXAIR and PCR-based ribotyping . Strain-specific and unique genotypic fingerprints were distinguished by these molecular typing strategies . The 29 strains of P . citronellolis were separated into 12 distinguishable genotypic groups by Rep-PCR and into seven genomic patterns by PCR-based ribotyping . The genetic diversity of the strains was related to the different geoclimatic isolation sites, type of oily sludge, and age of contamination of the sites . These results indicate that a combination of Rep-PCR fingerprinting and PCR-based ribotyping can be used as a high-resolution genomic fingerprinting method for elucidating intraspecies diversity among strains of P . citronellolis.

J Bacteriol, 2003 Mar, 185(6), 1995 - 2004
Identification and biosynthesis of cyclic enterobacterial common antigen in Escherichia coli; Erbel PJ et al.; Phosphoglyceride-linked enterobacterial common antigen (ECA(PG)) is a cell surface glycolipid that is synthesized by all gram-negative enteric bacteria . The carbohydrate portion of ECA(PG) consists of linear heteropolysaccharide chains 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 . The potential reducing terminal GlcNAc residue of each polysaccharide chain is linked via phosphodiester linkage to a phosphoglyceride aglycone . We demonstrate here the occurrence of a water-soluble cyclic form of enterobacterial common antigen, ECA(CYC), purified from Escherichia coli strains B and K-12 with solution nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and additional biochemical methods . The ECA(CYC) molecules lacked an aglycone and contained four trisaccharide repeat units that were nonstoichiometrically substituted with up to four O-acetyl groups . ECA(CYC) was not detected in mutant strains that possessed null mutations in the wecA, wecF, and wecG genes of the wec gene cluster . These observations corroborate the structural data obtained by NMR and ESI-MS analyses and show for the first time that the trisaccharide repeat units of ECA(CYC) and ECA(PG) are assembled by a common biosynthetic pathway.

J Antimicrob Chemother, 2003 Mar, 51(3), 631 - 8
Production of CTX-M-3 extended-spectrum beta-lactamase and IMP-1 metallo beta-lactamase by five Gram-negative bacilli: survey of clinical isolates from seven laboratories collected in 1998 and 2000, in the Kinki region of Japan; Yamasaki K et al.; The aim of this study was to research the distribution in the Kinki region of Japan of Enterobacteriaceae and Pseudomonas aeruginosa that produce extended-spectrum beta-lactamase (ESBL) and metallo beta-lactamase (MBL) . One thousand isolates, 200 of each of four enterobacterial species (i.e . Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Serratia marcescens) and 200 of P . aeruginosa, were collected from seven different laboratories during two 2 month periods, one in 1998 and one in 2000 . A double-disc synergy test (DDST) and 2-mercaptopropionic acid inhibition test (2-MPAT) were used to confirm beta-lactamase-producing isolates . The DDST was positive for one isolate of E . coli, five of K . pneumoniae, two of E . cloacae and 14 of S . marcescens . The 2-MPAT was positive for five isolates of S . marcescens and two of P . aeruginosa . We identified the beta-lactamase type of each isolate by molecular confirmatory tests (isoelectric focusing, PCR and DNA sequencing): CTX-M-3 ESBLs (three isolates of K . pneumoniae, two of E . cloacae and 13 of S . marcescens), CTX-M-2 ESBL (one isolate of K . pneumoniae), SHV-12 ESBLs (one isolate of E . coli and one of S . marcescens), CTX-M-3 and SHV-12 combination ESBL (one isolate of K . pneumoniae) and IMP-1 MBLs (five isolates of S . marcescens and two of P . aeruginosa) . In conclusion, many species of Gram-negative bacilli that produce CTX-M-3 ESBLs and IMP-1 MBLs were disseminated widely in different hospitals of the Kinki region of Japan . Therefore, monitoring of laboratory bacterial ecology seems important to stop the spread of these strains through nosocomial outbreaks.

J Antimicrob Chemother, 2003 Mar, 51(3), 625 - 30
Antimicrobial resistance in Cairo, Egypt 1999-2000: a survey of five hospitals; El Kholy A et al.; Antimicrobial resistance among bacterial pathogens is a global problem, but in Egypt data are sparse . We reviewed the antimicrobial susceptibility patterns of bloodstream isolates of Gram-positive cocci and Gram-negative bacilli in five hospitals in Cairo, Egypt, from 1999 to 2000 . In addition, susceptibilities of non-bloodstream isolates of Streptococcus pneumoniae and Enterococcus spp . were analysed . High rates of resistance were found in most of the bacteria studied . In the hospitals, a variety of methods were used for identification and susceptibility testing, but in the laboratories quality controlled strains were utilized routinely, to ensure accurate performance of the assays . Only 29% of Staphylococcus aureus isolates and 23% of coagulase-negative staphylococcal isolates were oxacillin susceptible . Both groups of staphylococci were also highly resistant to erythromycin, co-trimoxazole, clindamycin and doxycycline; all isolates were susceptible to vancomycin . Susceptibility of S . pneumoniae isolates to penicillin, ceftriaxone and fluoroquinolones was 63%, 84% and 82%, respectively . Vancomycin susceptibility of the enterococci was 96%; susceptibility to high-level gentamicin and streptomycin was 54% and 48%, respectively . Resistance to most relevant antimicrobials was commonplace among the Gram-negative bacilli; however, most remained susceptible to imipenem . The percentage of bloodstream isolates of Escherichia coli susceptible to common antimicrobial agents was as follows: ampicillin (6%), ampicillin-sulbactam (38%), co-trimoxazole (38%) and aminoglycosides (52%) . The susceptibility of isolates of E . coli, Klebsiella and Enterobacter spp . to ceftazidime was 62%, 40% and 46%, respectively . This suggests a potentially high rate of extended-spectrum beta-lactamase (ESBL) and/or Amp-C enzyme production . These results call for a nationwide surveillance programme to monitor microbial trends and antimicrobial resistance patterns in Egypt.

EMBO Rep, 2003 Feb, 4(2), 205 - 9
A single gene that promotes interaction of a phytopathogenic bacterium with its insect vector, Drosophila melanogaster; Basset A et al.; Insects are major vectors of plant and animal disease, and bacterial phytopathogens are often disseminated by flies . We have previously reported that some isolates of the phytopathogenic bacterial species Erwinia carotovora infect Drosophila and activate an immune response . Using a genetic screen, we have now identified two genes that are required by E . carotovora to infect Drosophila . One of these genes has a regulatory role whereas the other, evf, confers an infectious phenotype: its transfer to non-infectious Erwinia strains or to several enterobacteria improves survival in the gut and triggers the immune response . Overexpression of Erwinia virulence factor (evf) allowed bacteria to colonize the apical side of the gut epithelium and in some cases to spread to the body cavity . Our results demonstrate a specific interaction between plant pathogens and flies that promote their dissemination.

Nat Genet, 2003 Apr, 33(4), 514 - 7 Epub 2003 Mar 03.
Transcription-associated mutational asymmetry in mammalian evolution; Green P et al.; Although mutation is commonly thought of as a random process, evolutionary studies show that different types of nucleotide substitution occur with widely varying rates that presumably reflect biases intrinsic to mutation and repair mechanisms . A strand asymmetry, the occurrence of particular substitution types at higher rates than their complementary types, that is associated with DNA replication has been found in bacteria and mitochondria . A strand asymmetry that is associated with transcription and attributable to higher rates of cytosine deamination on the coding strand has been observed in enterobacteria . Here, we describe a qualitatively different transcription-associated strand asymmetry in mammals, which may be a byproduct of transcription-coupled repair in germline cells . This mutational asymmetry has acted over long periods of time to produce a compositional asymmetry, an excess of G+T over A+C on the coding strand, in most genes . The mutational and compositional asymmetries can be used to detect the orientations and approximate extents of transcribed regions.

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