Clin Infect Dis, 1996 Sep, 23(3), 543 - 9 Bacteremia due to Citrobacter species: significance of primary intraabdominal infection; Shih CC et al.; From 1982 to 1994, 45 patients (1.22 episodes per 10,000 discharged patients) were treated for citrobacter bacteremia at National Taiwan University Hospital (Taipei) . All patients had at least one underlying disease . Citrobacter bacteremia most commonly occurred in patients with malignancies (48.9%) or hepatobiliary stones (22.2%) . Intraabdominal tumors comprised the majority (59.1%) of malignancies . Bacteremia commonly originated from sites such as the abdominal cavity (51.1%), urinary tract (20%), and lung (11.1%) . Polymicrobial bacteremia was diagnosed in 15 patients (33.3%); for nine (60%) of these patients, the source of the infection was intraabdominal . Prior treatment with a third-generation cephalosporin was significantly associated (P < .01) with the development of multidrug resistance among the isolates . The mortality associated with citrobacter bacteremia was 17.8% . Poor prognostic factors included pneumonia, altered mental status on presentation, hypothermia, oliguria, septic shock, deterioration in mental status, hyperbilirubinemia, azotemia, and thrombocytopenia . Combination therapy, as compared with other regimens, improved the outcome of citrobacter bacteremia. Appl Environ Microbiol, 1996 Sep, 62(9), 3350 - 4 Confirmational identification of Escherichia coli, a comparison of genotypic and phenotypic assays for glutamate decarboxylase and beta-D-glucuronidase; McDaniels AE et al.; Genotypic and phenotypic assays for glutamate decarboxylase (GAD) and beta-D-glucuronidase (GUD) were compared for their abilities to detect various strains of Escherichia coli and to discriminate among other bacterial species . Test strains included nonpathogenic E . coli, three major groups of diarrheagenic E . coli, three other non-coli Escherichia species, and various other gram-negative and -positive bacteria found in water . The genotypic assays were performed with hybridization probes generated by PCR amplification of 670- and 623-bp segments of the gadA/B (GAD) and uidA (GUD) genes, respectively . The GAD enzymes catalyze the alpha-decarboxylation of L-glutamic acid to yield gamma-aminobutyric acid and carbon dioxide, which are detected in the phenotypic assay by a pH-sensitive indicator dye . The phenotypic assay for GUD involves the transformation of 4-methylumbelliferyl-beta-D-glucuronide to the fluorogenic compound 4-methylumbelliferone . The GAD phenotypic assay detected the majority of the E . coli strains tested, whereas a number of these strains, including all representatives of the O157:H7 serotype and several nonpathogenic E . coli strains, gave negative results in the GUD assay . Both phenotypic assays detected some but not all strains from each of the four Shigella species . A strain of Citrobacter freundii was also detected by the GUD assay but not by the GAD assay . All E . coli and Shigella strains were detected with both the gadA/B and uidA probes . A few Escherichia fergusonii strains gave weak hybridization signals in response to both probes at 65 degrees C but not at 68 degrees C . None of the other bacterial species tested were detected by either probe . These results were consistent with previous reports which have indicated that the GAD phenotypic assay detects a wider range of E . coli strains than does the GUD assay and is also somewhat more specific for this species . The genotypic assays for the two enzymes were found to be equivalent in both of these respects and superior to both of the phenotypic assays in terms of the range of E . coli strains and isolates detected. Antimicrob Agents Chemother, 1996 Aug, 40(8), 1926 - 30 Comparative characterization of the cephamycinase blaCMY-1 gene and its relationship with other beta-lactamase genes; Bauernfeind A et al.; A plasmidic beta-lactamase which hydrolyzed cephamycins was first detected and reported in 1989 . At that time its description was restricted to phenotypic characteristics . We analyzed nucleotide sequence of its gene and explored it genetic relationship with other bla genes . The deduced amino acid sequence of the blaCMY-1 product was compared with those of other known plasmidic cephamycinases and of chromosomal AmpC beta-lactamases . The results indicate that the relationship of CMY-1 is closest to MOX-1 among the plasmidic cephamycinases and to AmpC of Pseudomonas aeruginosa among the chromosomal cephalosporinases . We conclude that the plasmidic cephamycinases described up to now may be classified into three families, as follows: CMY-1, MOX-1, and FOX-1 with AmpC of P . aeruginosa; CMY-2, BIL-1 and LAT-1 with AmpC of Citrobacter freundii; and MIR-1 with AmpC of Enterobacter cloacae . Plasmidic cephamycinases are now recognized as clinically relevant class C beta-lactamases. APMIS, 1996 Jul-Aug, 104(7-8), 583 - 90 The influence of incubation conditions on the adherence of oral Enterobacteriaceae to HeLa cells; Sedgley CM et al.; The adherence of 12 oral isolates and 4 type strains of Enterobacteriaceae (equally representing Enterobacter cloacae, Klebsiella pneumoniae, Escherichia coli and Citrobacter freundii) to HeLa cell monolayers following five different incubation conditions (sucrose, D-mannose, serum, MEM and Candida albicans GDH 1957) was investigated . Incubation with sucrose and D-mannose resulted in the greatest and least adherence, respectively . The presence of preadherent C . albicans GDH 1957 on the HeLa cells tended to enhance the adherence of certain strains of E . cloacae and C . freundii, but had no overall impact on Enterobacteriaceae adherence . While heterogeneity of behaviour existed between strains within species, E . cloacae was the most, and K . pneumoniae the least, adherent species irrespective of incubation conditions . Haemagglutination assays indicated the presence of mannose-resistant type 1 fimbriae associated with all Enterobacteriaceae . In clinical terms, the variations in adherence properties observed in vitro may contribute to an understanding of the different prevalence rates of oral Enterobacteriaceae reported in the literature. Trans R Soc Trop Med Hyg, 1996 Jul-Aug, 90(4), 347 - 52 Royal Society of Tropical Medicine and Hygiene meeting at Manson House, London, 14 December 1995 . Enteropathogenic Escherichia coli--mucosal infection models; Frankel G et al.; The formation of attaching and effacing (A/E) lesions is central to the pathogenesis of enteropathogenic Escherichia coli (EPEC)-mediated disease in humans and Citrobacter rodentium-mediated transmissible colonic hyperplasia in mice . Closely related outer membrane proteins, known as intimins, are required for formation of the A/E lesion by both EPEC and C . rodentium . In this study we found similar ultrastructural damage in small intestinal biopsies from an EPEC-infected child and large bowel specimens from C . rodentium-infected mice . The C . rodentium-infected large bowel biopsies revealed massive hyperplastic reactions and the infected human small intestinal biopsies showed an increase in total crypt cell number and mitotic index . EPEC-infected small intestinal organ cultures revealed bacteria adhering in a localized pattern and evidence of A/E lesions . Covaspheres coated with a biologically active cell-binding domain of intimin also adhered to cells in a localized fashion but did not induce the characteristic A/E lesions. Antimicrob Agents Chemother, 1996 Jul, 40(7), 1736 - 40 Transferable cefoxitin resistance in enterobacteria from Greek hospitals and characterization of a plasmid-mediated group 1 beta-lactamase (LAT-2); Gazouli M et al.; Cefoxitin resistance in Klebsiella pneumoniae from Escherichia coli strains isolated in Greek hospitals was found to be due to the acquisition of similar plasmids coding for group 1 beta-lactamases . The plasmids were not self-transferable but were mobilized by conjugative plasmids . These elements have also been spread to Enterobacter aerogenes . The most common enzyme was a Citrobacter freundii-derived cephalosporinase (LAT-2) which differed from LAT-1 by three amino acids. J Clin Microbiol, 1996 Jul, 34(7), 1788 - 93 Evaluation of CHROMagar Orientation for differentiation and presumptive identification of gram-negative bacilli and Enterococcus species; Merlino J et al.; A new chromogenic plate medium, CHROMagar Orientation, was evaluated for use in the differentiation and presumptive identification of gram-negative bacilli and Enterococcus species by a multipoint inoculation (replicator) technique . In this study, 1,404 gram-negative bacilli and 74 enterococcal isolates were tested on CHROMagar Orientation . Six control American Type Culture Collection strains were also included with the testing to ensure quality control of the media . Of the Escherichia coli isolates (n = 588) tested, 99.3% produced a pink-to-red color . Only in four isolates that were O-nitrophenyl-beta-D-galactopyranoside (ONPG) negative did this result differ . Proteus mirabilis and P . vulgaris were well differentiated on this medium . P . mirabilis (n = 184) produced a clear colony with diffusible brown pigment around the periphery . By contrast, 15 of 16 P . vulgaris isolates produced bluish-green colonies with a slight brown background . All Aeromonas hydrophila isolates (n = 26) tested produced clear to pink colonies at 35 to 37 degrees C . This colony color changed to blue after 2 to 3 h of incubation at room temperature . A . hydrophila exhibited stronger color and better growth at 30 degrees C . Serratia marcescens (n = 29) demonstrated an aqua blue color that deepened to a darker blue when exposed to room temperature . All enterococcal isolates (n = 74) resulted in a blue color and gave pinpoint colonies on purity subcultures at 35 to 37 degrees C after 18 h of incubation . Similarity in color resulted in failure to discriminate accurately between Klebsiella, Enterobacter, and Citrobacter species . However, these species could be readily differentiated from other members of the family Enterobacteriaceae . Pseudomonas aeruginosa (n = 151) was easily differentiated from members of the Enterobacteriaceae but was less easily distinguishable from other gram-negative nonmembers of the Enterobacteriaceae . The medium was found to facilitate easy visual detection of mixed bacterial isolates in culture . When used in a replicator system, it easily detected mixed growths of organisms which may have otherwise led to false antibiotic susceptibility results . These mixed growths were not obvious on the routine susceptibility testing medium (Isosensitest). Am J Med, 1996 Jun 24, 100(6A), 45S - 51S Bacteriologic and clinical applications of a new extended-spectrum parenteral cephalosporin; Segreti J et al.; Although third-generation cephalosporins have been considered the backbone of antibiotic therapy for the treatment of many kinds of serious infections, including those in hospitalized patients, lack of activity against some important pathogens still exists among currently available drugs . In addition, increasing accounts of antibiotic resistance, particularly in the hospital environment, are of deep concern and have thus led to the need for the development of newer antimicrobial agents . Cefepime is a now parenteral cephalosporin with an extended spectrum of antibacterial activity that includes both aerobic gram-negative and gram-positive bacteria . It is also active against many gram-negative organisms resistant to ceftriaxone and cefotaxime, as well as many strains of Enterobacter and Citrobacter resistant to ceftazidime . Cefepime appears to be less likely to select out resistant organisms, and it may be less likely to change hospital flora than currently available antimicrobials . Cefepime has been shown to be very well tolerated and effective in the treatment of a variety of infections including moderate-to-severe pneumonia (including cases associated with concurrent bacteremia), complicated and uncomplicated urinary tract infections (also including cases associated with concurrent bacteremia), and skin and skin-structure infections . Clinical response rates are > or = 75% for most infections and have been comparable to ceftazidime in comparative trials . In addition, pretreatment susceptibility testing indicates that >94% of organisms isolated in patients enrolled in clinical trials were susceptible to cefepime. Am J Med, 1996 Jun 24, 100(6A), 26S - 38S Comparative activity of eight antimicrobial agents against clinical bacterial isolates from the United States, measured by two methods; Thornsberry C et al.; In a surveillance study conducted during 1992-1993 at 83 medical institutions of different types and sizes (e.g., laboratories, community hospitals, teaching hospitals) and from different geographical areas of the United States, clinical bacterial isolates were tested for their susceptibility to eight comparative antimicrobial agents (cefepime, ceftazidime, cefotaxime, ceftriaxone, ciprofloxacin, gentamicin, imipenem, and piperacillin) . A total of 12,574 isolates were tested by either the Etest method (AB Biodisk) or a microdilution method (MicroScan) in the participating laboratories; 11.8% of these isolates were subsequently retested for quality assurance purposes by both methods in a central laboratory . The results obtained in the central laboratory were essentially the same as the results obtained in the participating laboratories . This article presents data for gram-negative and gram-positive isolates other than Streptococcus pneumoniae, the results of which have been previously published . Antimicrobial susceptibility results obtained with the two different minimum inhibitory concentration (MIC) methods--MicroScan and Etest--showed that most isolates of Enterobacteriaceae were susceptible to cefepime, exceeding the activity of ceftazidime, ceftriaxone, and cefotaxime, principally because of the greater activity of cefepime against the species that produce Bush group 1 beta-lactamases (predominantly Enterobacter cloacae, Enterobacter aerogenes, and Citrobacter freundii) . In addition, the activity of cefepime against Pseudomonas aeruginosa isolates was essentially equivalent to that of ceftazidime and greater than that of third-generation cephalosporins . Most methicillin-susceptible Staphylococcus aureus were susceptible to all the cephalosporins, whereas methicillin-resistant S . aureus and enterococci were resistant . Overall, the most active antimicrobials in this study were imipenem, ciprofloxacin, and cefepime, but the activity of all the antimicrobials varied with different species . Categorically, the results from the microdilution and Etest methods were equivalent. Am J Med, 1996 Jun 24, 100(6A), 13S - 19S Susceptibility of bacterial isolates to beta-lactam antibiotics from U.S . clinical trials over a 5-year period; Kessler RE et al.; Results are reported for agar dilution susceptibility testing of 3,075 isolates of aerobic bacteria collected from >200 U.S . institutions, located in 30 different states . These isolates were collected from 1987 through 1991 from patients who participated in cefepime clinical trials . Cefepime susceptibility was compared with ceftazidime, cefotaxime, ceftriaxone, cefoperazone, and imipenem . To avoid duplication of strains, only initial isolates were included . Cefepime minimum inhibitory concentration (MIC90) values for Enterobacteriaceae were < or = 0.5 microg/mL, except for two species, Citrobacter freundii and Providencia stuartii, with MIC90 values of 2 and 1, respectively . The MIC90 values of the other cephalosporins were higher, especially for Enterobacter aerogenes and C . freundii . The MIC90 values of cefepime for methicillin-susceptible Staphylococcus aureus (4 microg/mL) and Pseudomonas aeruginosa (8 microg/mL) were similar to those of cefotaxime for S . aureus (4 microg/mL), and to ceftazidime for P . aeruginosa (8 microg/mL) . Streptococcus pneumoniae was similar in susceptibility to cefotaxime at 0.06 microg/mL . The activity of cefepime against a diverse group of gram-positive and gram-negative (1987-1991) bacteria isolates demonstrates the excellent activity of cefepime compared to third-generation cephalosporins and imipenem, particularly among C . freundii and E . aerogenes isolates, which were often resistant to other cephalosporins. J Appl Bacteriol, 1996 Jun, 80(6), 659 - 66 Use of two 16S DNA targeted oligonucleotides as PCR primers for the specific detection of Salmonella in foods; Lin CK et al.; A 16S DNA targeted polymerase chain reaction (PCR) method specific for the detection of Salmonella isolates with various serotypes was developed . The primers used for such a PCR method were 16SF1 and 16SIII . 16SF1 is the reverse and complementary strand of 16SI which has been shown to be able to hybridize with Salmonella and Citrobacter spp . 16III on the other hand, is able to hybridize with Klebsiella and Serratia spp . in addition to Salmonella . Although 16SF1 and 16SIII were not specific to Salmonella only, when they were used as PCR primers, only the Salmonella isolates could be specifically detected . The interference from Citrobacter, Klebsiella and Serratia spp . could be prevented . None of the other non-Salmonella isolates including strains of the family of Enterobacteriaceae closely related to Salmonella would generate the false-positive reaction . When this PCR system was used for the detection of Salmonella cells artificially contaminated in food samples, results obtained were satisfactory . A detection limit of N x 10(0) cells per assay could be obtained. J Immunol, 1996 Jun 1, 156(11), 4466 - 73 Inhibition of the hemolytic activity of the first component of complement C1 by an Escherichia coli C1q binding protein; van den Berg RH et al.; Molecular mimicry is a well established mechanism via which bacteria protect themselves from complement-mediated killing . We have previously demonstrated that a number of human cells express receptors for C1q (C1qR) and that the soluble form of this receptor inhibits activation of the classical pathway of complement . We now investigated whether Escherichia coli possesses a C1qR-like protein that protects these bacteria from complement-mediated injury . By FACS analysis it was shown that approximately 60% of the bacteria bound C1q directly in the absence of Abs . With ELISA we confirmed that the bacterial cell envelope was able to bind C1q in a dose-dependent fashion . We isolated a cell envelope associated C1q binding protein (C1qBP) by C1q affinity chromatography, then by anion exchange chromatography and gel filtration chromatography . On SDS-PAGE, the m.w . of C1qBP appeared to be 57 kDa and 51 kDa under reducing and nonreducing conditions, respectively . It was demonstrated that C1qBP specifically binds C1q and inhibits the hemolytic activity of C1q in both a dose- and time-dependent fashion . The binding of C1qBP to C1q is inhibited by C1q itself and also by the collagen-like stalks and the globular heads of C1q . In this respect, bacterial C1qBP is different from human C1qR because the binding of C1q to C1qR is only inhibited by the collagen-like stalks of C1q and not by the globular heads of C1q . C1qBP, when bound to C1q, prevents the assembly with C1r and C1s to form a functional C1 complex . The occurrence of C1qBP is not limited to certain E . coli strains, but is also found on Staphylococcus aureus, Citrobacter freundii, and Pseudomonas aeruginosa . Also, the binding of 125(I)-labeled C1q to these bacteria is specific because the binding of C1q to these bacteria is inhibitable with isolated soluble C1qBP . These findings provide evidence for the existence of a C1qR-like protein on bacteria that might protect them from complement-mediated damage. J Bacteriol, 1996 Jun, 178(11), 3072 - 6 Growth suppression in early-stationary-phase nutrient broth cultures of Salmonella typhimurium and Escherichia coli is genus specific and not regulated by sigma S; Barrow PA et al.; We have studied the growth suppression seen in early-stationary-phase LB broth cultures of Salmonella typhimurium . Multiplication of small numbers of an antibiotic-resistant S . typhimurium mutant was prevented when the mutant was added to 24-h cultures of the antibiotic-sensitive parent strain, whereas an antibiotic-resistant mutant of an Escherichia coli strain added to the same culture grew well . A 24-h E . coli culture produced a similar specific bacteriostatic inhibition against E . coli . In older cultures, a specific bactericidal effect similar to that observed by M . M . Zambrano and R . Kolter (J . Bacteriol . 175:5642-5647, 1993) was also observed . Whether incubated statically or shaken, sufficient nutrients were present in the filtered supernatants of 24-h cultures for small inocula of the same strain to multiply to ca . 10(9) CFU/ml after reincubation . Introduction of the rpoS mutation had no effect on the specific bacteriostatic inhibition . Similar specific inhibition was also observed in strains of Citrobacter freundii, Klebsiella pneumoniae, Enterobacter agglomerans, and Shigella spp . Experiments in which the 24-h culture was physically separated from the antibiotic-resistant mutant by using a dialysis membrane were carried out . These results indicated that the inhibition might be mediated by a diffusible but labile chemical mediator. Gig Sanit, 1996 May-Jun, (3), 22 - 3 {Enterobacteria isolated from commercial fishes from the Volga-Caspian basin}; Lartseva LV et al.; Enteric bacteria, such as Proteus, Citrobacter {correction of Cytobacter}, and Providencia, were found to be prevalent particularly in the gills and intestines of marketable fishes of the Volga and Caspian Seas . Half of all the enteric bacteria was detected in the fish kidneys, spleen, and liver . This shows it necessary to standardize different types of fish raw materials. Lett Appl Microbiol, 1996 May, 22(5), 378 - 80 The use of a rapid Salmonella latex serogrouping test (Spectate) to assist in the confirmation of ELISA-based rapid Salmonella screening tests; Cheesbrough S et al.; Spectate, a 10 min, simple, latex-based agglutination test for serogrouping of salmonellae, has been investigated as a tool to assist in the confirmation of ELISA presumptive positive broth samples when screening for salmonellae in foods . When obtaining a combined ELISA and Spectate positive result, there was a 90% (27/30) confidence limit of a genuine positive result, some one or two working days quicker than the traditional methods . Of the 10% (3/30) that were not confirmed as salmonellas, two gave a Spectate result which is advised as being a possible Citrobacter spp . and one sample gave a positive confirmation by Spectate only, which suggested a failure of the traditional confirmation process, a finding confirmed at other sites . Extensive studies performed at several food company microbiology laboratories showed Spectate to be a useful additional tool in the confirmation process of ELISA screening techniques for salmonellae in food . Additionally the concept of a "false positive' may need to be refined to that of a "not culturally' positive, given the apparent possible failure of the traditional confirmation methods. Z Naturforsch {C}, 1996 May-Jun, 51(5-6), 363 - 70 The catalytic mechanism of tyrosine phenol-lyase from Erwinia herbicola: the effect of substrate structure on pH-dependence of kinetic parameters in the reactions with ring-substituted tyrosines; Faleev NG et al.; Apparently homogeneous tyrosine phenol-lyase (TPL) from Erwinia herbicola has been prepared by a new method . The pH-dependencies of the main kinetic parameters for the reactions of Erwinia TPL with tyrosine, 2-fluorotyrosine, 3-fluorotyrosine, 2-chlorotyrosine, and 3,4-dihydroxyphenylalanine (DOPA) have been studied . The pattern of pH-dependence of V(max) depends on the nature of the substituent in the aromatic ring . For the substrates bearing small substituents (H, 2-F, 3-F) V(max) values were found to be pH-independent . For 2-chlorotyrosine and DOPA V(max) decreased at lower pH, the effect being described by equation with one pKa . Generally two bases are reflected in the pH dependence of V(max)/Km . The first base, probably is responsible for the abstraction of alpha-proton, while the second one, interacts with the phenolic hydroxyl at the stage of binding . The reaction of TPL with DOPA differs from the reactions with other tyrosines by the requirement of an additional base which is reflected in the pH-profiles of both V(max) and V(max)/Km . For the reaction of TPL from Citrobacter intermedius with DOPA only V(max)/Km values could be determined . The activity of Citrobacter enzyme towards DOPA is considerably less than that of E . herbicola enzyme, and its maximal value is attained at higher pH. Enferm Infecc Microbiol Clin, 1996 Apr, 14(4), 211 - 4 {Fluoroquinolone and aminoglycoside resistance in chromosomal cephalosporinase-overproducing gram-negative bacilli strains with inducible beta-lactamase}; Lopez-Yeste M et al.; INTRODUCTION . The increasing prevalence of stable derepressed mutants over-producers of type I chromosomal cephalosporinase in inducible Enterobacteriaceae and Pseudomonas aeruginosa challenges the adequacy of third generation cephalosporins in the empirical treatment of certain nosocomial infections . We sought to determine the frequency of stable over-producers of type I enzyme and their associated resistance to fluoroquinolones and aminoglycosides . METHODS . Disc-diffusion and MIC determinations to extended-spectrum beta-lactams, imipenem, ciprofloxacin and gentamicin were performed in all cell isolates of inducible enteric bacteria (Enterobacter spp., Citrobacter spp., Serratia spp., Morganella morganii, Providencia spp.) and P . aeruginosa collected during the period of study (1992-1993) . RESULTS . A total of 1,426 isolates of inducible enteric bacteria and P . aeruginosa were studied . Each one represented a single patient . Among the 511 isolates of enteric bacteria 15.1% of strains were found to be stable derepressed mutants (Serratia 2.2%; Morganella spp., 3%; Providencia and Proteus 3%; Citrobacter spp., 10%; Enterobacter spp., 23.6%); among the 916 P . aeruginosa isolates studied, 9.2% were stable over-producers . Among Citrobacter, Providencia and Proteus spp., 53.1% of stable over-producers were resistant to ciprofloxacin versus 20.2% of non-over-producers (p < 0.01); in P . aeruginosa, 35.3% of over-producers were resistant to gentamicin versus 25.0% in non-over-producers (p < 0.01) . CONCLUSION . The prevalence of stable derepressed mutants is high among enteric bacteria and P . aeruginosa with type I inducible beta-lactamase . These strains frequently exhibit resistance to fluoroquinolones and aminoglycosides, reducing considerably the available therapeutic options. FEMS Microbiol Lett, 1996 Apr 1, 137(2-3), 141 - 6 Iron utilization studies in Citrobacter species; Khashe S et al.; Seventy-one strains of Citrobacter were screened for iron scavenging mechanisms by biologic and chemical assays . Essentially all citrobacteria (70/71) were found to elaborate enterobactin-like siderophores by both biologic and chemical assays, however only c . koseri (C . diversus) was found to produce aerobactin . The concentration of ethylenediamine di(o-hydroxyphenylacetic acid) (EDDA) required to inhibit the growth of individual Citrobacter strains by depleting free iron ranged from 250 micrograms/ml to 100 micrograms/ml . Iron utilization studies of selected citrobacter isolates indicated that hemin and hematin could reverse the effects of iron limitation on growth under iron-stressed conditions (1000 micrograms/ml of EDDA) . Two C . koseri strains grown under iron-restricted conditions showed similar changes in their whole cell protein profiles including induction of high molecular mass proteins (72-83 kDa) which may play a role in iron acquisition under iron-stressed conditions . The collective results support an additional virulence-associated mechanism for C . koseri strains which may help explain the greater pathogenic potential this group has for causing serious extraintestinal disease in humans. Appl Environ Microbiol, 1996 Apr, 62(4), 1448 - 51 3-Hydroxypropionaldehyde, an inhibitory metabolite of glycerol fermentation to 1,3-propanediol by enterobacterial species; Barbirato F et al.; Glycerol fermentation by Enterobacter agglomerans revealed that both growth and 1,3-propanediol production ceased after consumption of about 430 mM glycerol, irrespective of the initial glycerol content . This phenomenon was assigned to the production of 3-hydroxypropionaldehyde, which was identified by proton nuclear magnetic resonance and which showed a bacteriostatic effect . The accumulation during glycerol fermentation was also observed with two other enterobacterial species, i.e., Klebsiella pneumoniae and Citrobacter freundii. Jpn J Antibiot, 1996 Apr, 49(4), 338 - 51 {Antibacterial activity of sulopenem, a new parenteral penem antibiotic}; Inoue E et al.; Sulopenem, a new penem antibiotic, was compared with other antibiotics with regard to in vitro antibacterial and bactericidal activities, stabilization against beta-lactamases, and effect on the release of lipopolysaccharide from Gram-negative bacteria . The results are summarized as follows . 1 . Sulopenem showed more potent activities than other antibiotics against both Gram-positive and Gram-negative bacteria except Pseudomonas aeruginosa . 2 . Sulopenem showed potent bactericidal activities (MIC/MBC) against both Gram-positive and Gram-negative bacteria . Time kill studies against Staphylococcus aureus, Escherichia coli, Enterobacter cloacae and Citrobacter freundii showed potent bactericidal activities of sulopenem . 3 . Sulopenem was found to possess a stronger activity than other antibiotics against beta-lactamase-producing strains except P . aeruginosa and Stenotrophomonas maltophilia . 4 . In particular, sulopenem was found to be more stable to the hydrolysis by various beta-lactamases produced by Gram-negative bacteria than any other antibiotics tested . Vmax/Km values of sulopenem were smaller than those of cefotiam for all tested beta-lactamases, which reflected a broad antibacterial spectrum of sulopenem . 5 . E . coli ML4707 exposed to sulopenem and imipenem released less endotoxin than did controls at all concentration ranges tested . In contrast, the strain exposed to ceftazidime at bacteriostatic concentrations released a large amount of endotoxin. FEMS Immunol Med Microbiol, 1996 Apr, 13(4), 261 - 8 The occurrence of glycine in bacterial lipopolysaccharides; Gamian A et al.; The aminoacyl analysis of endotoxic lipopolysaccharides (LPS) isolated from several bacteria revealed essential amounts of glycine, among the inherent LPS components . Significant amounts of the glycine was detected in lipopolysaccharides isolated from over 30 strains of Escherichia, Salmonella, Hafnia, Citrobacter and Shigella species . Glycine as a single amino acid was found only in a core part of LPS . Molar ratio of glycine in core oligosaccharide fraction ranged from 0.2 to 0.6 per 3 heptoses . The oligosaccharide enriched in glycine was isolated using the HPLC . The amino acid appeared to be terminally located in a core oligosaccharide . The labelling of the lipopolysaccharide cores was achieved when the bacteria were cultivated in the presence of radioactive {14C}glycine . The labelled core oligosaccharide released the radioactivity during treatment with mild alkali or acid (0.1 M NaOH or HCl, 100 degrees C, 4 h) . The radioactivity in SDS-polyacrylamide gel electrophoresis migrated exclusively with LPS . The results indicate that amino acid is an integral constituent of core oligosaccharide in lipopolysaccharide. Biotechnol Appl Biochem, 1996 Apr, 23 ( Pt 2), 149 - 54 Affinity purification and binding characteristics of Citrobacter freundii AmpR, the transcriptional regulator of the ampC beta-lactamase gene; Roh IK et al.; The transcriptional regulator of the Citrobacter freundii ampC beta-lactamase gene, AmpR, was purified as a single SDS/PAGE-gel band by using various techniques, including DNA-Sepharose 4B affinity chromatography . The purified AmpR consisted of a 32.5 kDa monomer that interacted with three operator sequences: two binding sequences, at positions -75 to -70 and -67 to -51 with respect to the transcriptional start site, were located in the LysR motif (-72 to -60), and the third sequence was at position -43 to -38 . Equilibrium binding studies raise the possibility that the adjacent operator sequence could exert a positive influence on the ability of AmpR to bind to these sites. J Bacteriol, 1996 Apr, 178(7), 2094 - 101 Isolation, identification, and transcriptional specificity of the heat shock sigma factor sigma32 from Caulobacter crescentus; Wu J et al.; We report the identification of the Caulobacter crescentus heat shock factor sigma32 as a 34-kDa protein that copurifies with the RNA polymerase holoenzyme . The N-terminal amino acid sequence of this protein was determined and used to design a degenerate oligonucleotide as a probe to identify the corresponding gene, rpoH, which encodes a predicted protein with a molecular mass of 33,659 Da . The amino acid sequence of this protein is similar to those of known bacterial heat shock sigma factors of Escherichia coli (41% identity), Pseudomonas aeruginosa (40% identity), and Citrobacter freundii (38% identity) . The isolated C . crescentus gene complements the growth defect of an E . coli rpoH deletion strain at 37 degrees C, and Western blot (immunoblot) analysis confirmed that the gene product is related to the E . coli sigma32 protein . The purified RpoH protein in the presence of RNA polymerase core enzyme specifically recognizes the heat shock-regulated promoter P1 of the C . crescentus dnaK gene, and base pair substitutions in either the -10 or -35 region of this promoter abolish transcription . S1 nuclease mapping indicates that rpoH transcripts originate from two promoters, P1 and P2, under the normal growth conditions . The P2 promoter is similar to the sigma32 promoter consensus, and the P2-specific transcript increases dramatically during heat shock, while the P1-specific transcript remains relatively constant . These results suggest that although the structure and function of C . crescentus sigma32 appear to be very similar to those of its E . coli counterpart, the C . crescentus rpoH gene contains a novel promoter structure and may be positively autoregulated in response to environmental stress. Mikrobiol Z, 1996 Mar-Apr, 58(2), 3 - 7 {Enterobacteria in areas of water along the Crimean coast}; Puchenkova SG; Characteristic of coliform bacteria in the coastal sea ecosystems is given . A decrease of Escherichia coli indicator value was ascertained and presence of Klebsiella sp . and Citrobacter freundii was revealed, in the sea areas with high level of anthropogenic load . Wide distribution of bacteria of Enterobacter agglomerans kind was determined in the sea substrates and their stability to unfavourable influences was shown. J Bacteriol, 1996 Mar, 178(5), 1363 - 73 Identification of TonB homologs in the family Enterobacteriaceae and evidence for conservation of TonB-dependent energy transduction complexes; Larsen RA et al.; The transport of Fe(III)-siderophore complexes and vitamin B12 across the outer membrane of Escherichia coli requires the TonB-dependent energy transduction system . A set of murine monoclonal antibodies (MAbs) was generated against an E . coli TrpC-TonB fusion protein to facilitate structure and function studies . In the present study, the epitopes recognized by these MAbs were mapped, and their distribution in gram-negative organisms was examined . Cross-species reactivity patterns obtained against TonB homologs of known sequence were used to refine epitope mapping, with some epitopes ultimately confirmed by inhibition experiments using synthetic polypeptides . Epitopes recognized by this set of MAbs were conserved in TonB homologs for 9 of 12 species in the family Enterobacteriaceae (including E . coli), including previously unidentified TonB homologs in Shigella, Citrobacter, Proteus, and Kluyvera species . These homologs were also detected by a polyclonal alpha-TrpC-TonB serum that additionally recognized the known Yersinia enterocolitica TonB homolog and a putative TonB homolog in Edwardsiella tarda . These antibody preparations failed to detect the known TonB homologs of either Pseudomonas putida or Haemophilus influenzae but did identify potential TonB homologs in several other nonenteric gram-negative species . In vivo chemical cross-linking experiments demonstrated that in addition to TonB, auxiliary components of the TonB-dependent energy transduction system are broadly conserved in members of the family Enterobacteriaceae, suggesting that the TonB system represents a common system for high-affinity active transport across the gram-negative outer membrane. Antimicrob Agents Chemother, 1996 Feb, 40(2), 454 - 9 Chromosomal beta-lactamase genes of Klebsiella oxytoca are divided into two main groups, blaOXY-1 and blaOXY-2; Fournier B et al.; The chromosomally encoded beta-lactamase gene (blaOXY-2) of the wild-type Klebsiella oxytoca SL911 was cloned and sequenced . Its nucleotide sequence similarity with the previously sequenced K . oxytoca beta-lactamase gene (blaOXY-1) (Y . Arakawa, M . Ohta, N . Kido, M . Mori, H . Ito, T . Komatsu, Y . Fujii, and N . Kato, Antimicrob . Agents Chemother . 33:63-70, 1989) is 87.3%, and its amino acid similarity is 89.7% . This group of K . oxytoca beta-lactamases is related to chromosomal beta-lactamases of Citrobacter diversus, Proteus vulgaris, and Yersinia enterocolitica and to the plasmid-mediated extended-spectrum beta-lactamases MEN-1 and Toho-1 . By colony hybridization with 86 strains susceptible and resistant to aztreonam, isolated in six countries, K . oxytoca beta-lactamase genes hybridized with either a specific blaOXY-1 DNA probe (668 bp) or a blaOXY-2 DNA probe (723 bp) . Thus, beta-lactamase genes could be divided into two groups: blaOXY-1 (47% of the strains) and blaOXY-2 (53% of the strains) . A study of isoelectric points confirmed the great variability reported in the literature . However, the two beta-lactamase groups were each represented by four different pIs: for OXY-2, 5.2, 5.7, 6.4, and 6.8, with the 5.2 form representing 59% of all OXY-2 enzymes, and for OXY-1, 7.1, 7.5, 8.2, and 8.8, with the 7.5 form representing 88% of all OXY-1 enzymes. Can J Microbiol, 1996 Feb, 42(2), 107 - 14 Distribution of diaminopropane and acetylspermidine in Enterobacteriaceae; Hamana K; Polyamines of 97 strains (60 species) belonging to 18 genera of the family Enterobacteriaceae were determined by high performance liquid chromatographic analysis . In addition to putrescine and cadavarine, diaminopropane was widely distributed in Enterobacteriaceae and almost ubiquitously within Enterobacter, Pantoea, Erwinia, Leminorella, Proteus, Leclercia, Morganella, Klebsiella, Hafnia, Rahnella, Serratia, and Tatumella species and sporadically within Citrobacter, Escherichia, Moellerella, Providencia, Yokenella, and Yersinia species . Histamine was detected in some cultures of Proteus and Morganella . Agmatine was sporadically spread . Heterogeneity in the occurrence of spermidine was observed within the spermidine-containing cultures . Distribution profiles of 18 genera . Acetylated spermidine was found concomitantly in the spermidine-containing cultures . Distribution profiles of diaminopropane, spermidine, and acetylspermidine in Enterobacteriaceae can serve as a chemotaxonomic marker to distinguish this family from other taxa of the gamma subclass of the class Proteobacteria. J Mol Biol, 1996 Jan 12, 255(1), 176 - 86 Crystal structure of Citrobacter freundii restriction endonuclease Cfr10I at 2.15 A resolution; Bozic D et al.; The X-ray crystal structure of Citrobacter freundii restriction endonuclease Cfr10I has been determined at a resolution of 2.15 A by multiple isomorphous replacement methods and refined to an R-factor of 19.64% . The structure of Cfr10I represents the first structure of a restriction endonuclease recognizing a degenerated nucleotide sequence . Structural comparison of Cfr10I with previously solved structures of other restriction enzymes suggests that recognition of specific sequence occurs through contacts in the major and the minor grooves of DNA . The arrangement of the putative active site residues shows some striking differences from previously described restriction endonucleases and supports a two-metal-ion mechanism of catalysis. Antibiot Khimioter, 1996, 41(12), 7 - 13 {Characterization of antimicrobial properties of cefpirome}; Sidorenko SV et al.; The results of a multicentre investigation of antibiotic susceptibility in 800 clinical isolates were analyzed . The levels of susceptibility to cefpirome and other antibiotics in gram-negative organisms with inducable production of chromosomal beta-lactamases (Enterobacter, Serratia, Citrobacter and others) were compared and the advantages of cefpirome over other cephalosporins were shown: 89 per cent of the susceptible strains against 58 to 78 per cent . With respect to other microorganisms the advantages of cefpirome were less pronounced. Postepy Hig Med Dosw, 1996, 50(5), 459 - 72 {Lipopolysaccharides containing sialic acid}; Gamian A; Sialic acids which are important constituents of animal tissue glycoconjugates are also present in antigens of some bacterial strains . Capsular polysaccharides with sialic acid have been extensively studied whereas little is known on lipopolysaccharides which contain sialic acid . The paper presents review of the data concerning structure of bacterial endotoxic lipopolysaccharides . Methodological peculiarities were described . Specially emphasized were endotoxins of Escherichia coli O24, O56, O104, Salmonella toucra O48, Citrobacter freundii O37 and Hafnia alvei strain PCM2386. Microbiol Immunol, 1996, 40(12), 915 - 21 Re-speciation of the original reference strains of serovars in the Citrobacter freundii (Bethesda-Ballerup group) antigenic scheme of West and edwards; Miki K et al.; The antigenic scheme for the Bethesda-Ballerup group of bacteria established by West and Edwards in 1954 has continued to be applied as a serotyping scheme for Citrobacter freundii . In 1993, however, the classification of the Citrobacter was drastically revised and the species C . freundii redefined by Brenner et al . Accordingly, to judge the propriety to continuously use a single antigenic scheme for the C . freundii complex, the 90 reference strains listed in the antigenic scheme for C . freundii by West and Edwards were characterized phenotypically and specified based on the revised classification . Of these 90 strains, two strains of Hafnia alvei and one of Escherichia coli were found . Among the remaining 87 reference strains, Citrobacter youngae was the predominant species (40 strains), followed by Citrobacter braakii (25 strains), Citrobacter werkmanii (13 strains), and the unnamed Citrobacter genospecies 10 of Brenner et al (six strains) . Citrobacter freundii, as redefined, accounted for only three strains and ranked behind the other four species . No overlapping with most of the 42 O-groups and 82 H-antigens was recognized between species with few exceptions . O-groups 1-9 inclusive, which were estimated to represent more than 90% of the former C.freundii strains, occurred in strains of C . youngae and C . braakii; and all nine strains of O-group 29, formerly known as the Ballerup group, were identified as C . braakii . These findings suggest that further study of the serotyping system is needed for all H2S-producing Citrobacter species. Ann Pharm Fr, 1996, 54(6), 276 - 9 Screening of in vitro antibacterial activity from Syzygium Guineense (Willd) hydrosoluble dry extract; Tsakala TM et al.; Diarrhoea is one of the most important causes of infant mortality in the world . As modern drugs are expensive or unavailable in developing countries, many people use traditional medicines in Africa for the treatment of several diseases . In our study, we investigated the antibacterial activity of Syzygium Guineense extract in order to assess its activity on some bacterial strains involved in diarrhoeal diseases and to justify its use . The aqueous dry extract was prepared by decoction followed by evaporating to dryness and tested according to dilution method . This extract showed an antibacterial activity against some bacterial strains: Salmonella E., Shigella D., Shigella F., E . Coli., Enterobacter A . It did not show any activity against Citrobacter F., Proteus M., Klebsiella P . Storage conditions (27 degrees C, glass flask) did not affect antibacterial properties of the extract. Microbios, 1996, 86(349), 205 - 12 A simple method to detect bacteriolytic enzymes produced by enterobacteriaceae; Branca G et al.; The production of bacteriolytic enzymes by Enterobacteriaceae in various growth conditions was investigated . Peptone-based media containing killed Gram-negative cells facilitated detection of bacteriolytic enzyme production in the highest number of species . These belonged to the genera Serratia, Proteus, Morganella and Providencia . In contrast, Escherichia coli, Shigella, Salmonella, Klebsiella, Enterobacter and Citrobacter species did not produce bacteriolytic activities in any of the conditions tested. FEMS Immunol Med Microbiol, 1996 Jan, 13(1), 1 - 8 Structural and serological studies of lipopolysaccharides of Citrobacter O35 and O38 antigenically related to Salmonella; Kocharova NA et al.; Structural analysis using 13C NMR spectroscopy and methylation showed that lipopolysaccharides (LPSs) of Citrobacter freundii O35 and Salmonella arizonae O59 have structurally identical O-specific polysaccharide chains, and those of C . freundii O38 and Salmonella kentucky differ only in the presence of O-acetyl groups in the former . Serological relationships between the structurally similar LPSs were demonstrated using inhibition of ELISA, rocket immunoelectrophoresis, double gel diffusion, and immunoblotting . The O-acetyl groups present in C . freundii O38 LPS are of little importance for its serological specificity . A cross-reaction was observed in immunoblotting between O-antisera to C . freundii O35 and S . arizonae O59 and a structurally related LPS of Pseudomonas aeruginosa O11a, 11b (Lanyi-Bergan classification). Antimicrob Agents Chemother, 1996 Jan, 40(1), 221 - 4 Characterization of the plasmidic beta-lactamase CMY-2, which is responsible for cephamycin resistance; Bauernfeind A et al.; The phenotype of Klebsiella pneumoniae HEL-1 indicates a plasmidic cephamycinase gene (blaCMY-2) . Its sequence shows one open reading frame coding for a protein of 381 amino acids . CMY-2 is classified as class C beta-lactamase that is closely related to the plasmidic enzymes BIL-1 and LAT-1 and the chromosomal AmpC of Citrobacter freundii . The blaCMY-2 gene possibly was translocated onto a plasmid of C . freundii which spread to K . pneumoniae. Ann Urol (Paris), 1996, 30(3), 108 - 11 Citrobacter emphysematous pyelonephritis in a tuberculous kidney caused by citrobacter . A case report in a diabetic patient; Fischer C et al.; Emphysematous pyelonephritis caused by gas-producing bacteria like Escherichia coli or Klebsiella pneumonia is generally observed in female diabetic patients . We report a case in which Citrobacter was the microbiologically documented pathogen . High-dose antibiotic regimen was administered, but nephrectomy was necessary to overcome the life-threatening situation. Chemotherapy, 1996 Jan-Feb, 42(1), 11 - 20 Comparative evaluation of orally active antibiotics against community-acquired pathogens: results of eight European countries; Cullmann W; In this multicenter study conducted in eight European countries, 13,173 pathogens--all isolated from community-acquired infections in 1992 and 1993--were evaluated for their susceptibility to the following orally active antibiotics: penicillin G, ampicillin, amoxycillin plus clavulanic acid, cefaclor, cefuroxime, cefetamet, doxycycline and erythromycin . Ten centers in Italy, five in Germany, in the Netherlands and Switzerland, four in Greece and Spain, three in Hungary and one in Finland contributed to this study; ready-to-use standardized microtiter panels (Sceptor system, BBL, Heidelberg, Germany) were used throughout all assays . The most frequently encountered species were: Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae and non-typhoid Salmonella spp., Enterobacter cloacae, Streptococcus agalactiae, Haemophilus influenzae, Citrobacter freundii, Staphylococcus pyogenes, Streptococcus pneumoniae, Proteus vulgaris, Moraxella catarrhalis and Shigella spp . The percentage of susceptible isolates was assessed for each of the above-mentioned countries and European-wide with all the data available . For many species, the percentage of resistant isolates did not differ markedly between the countries considered . However, one of the most striking exceptions was the high prevalence of high-level penicillin-G-resistant S . pneumoniae isolates in Hungary and Spain; some of the low-level penicillin-G-resistant strains remained susceptible to cefuroxime, whereas complete cross-resistance occurred for all other beta-lactams studied . The high frequency of ampicillin-resistant H . influenzae isolates in Spain deserves mentioning; this could be attributed mainly to the prevalence of a beta-lactamase, as the addition of clavulanic acid rendered these strains susceptible to ampicillin . The penicillin compounds exhibited the greatest activity against Gram-positive pathogens, whereas cefetamet was the most active agent against Gram-negative pathogens with a well-balanced spectrum of activity. J Clin Microbiol, 1996 Jan, 34(1), 76 - 9 Outbreak of TEM-24-producing Enterobacter aerogenes in an intensive care unit and dissemination of the extended-spectrum beta-lactamase to other members of the family enterobacteriaceae; Neuwirth C et al.; We report an outbreak of Enterobacter aerogenes in an intensive care unit (ICU) and two medicine departments that produced the extended-spectrum beta-lactamase TEM-24, which was difficult to detect by disk agar diffusion . The strains were compared by DNA restriction fragment length polymorphism after pulsed-field gel electrophoresis following cleavage with XbaI . This typing method indicated that a single strain, first isolated in the ICU, spread throughout the other medical departments as a result of patient transfer . We also observed the transfer in vivo of the plasmid encoding TEM-24 from the strain of Enterobacter aerogenes to different strains of Escherichia coli and Citrobacter freundii in the ICU . It therefore appears that the epidemic involved results from two events: dissemination of one strain of Enterobacter aerogenes and dissemination of the plasmid encoding TEM-24 among various members of the family Enterobacteriaceae. Acta Clin Belg, 1996, 51(1), 28 - 35 Belgian multicentre study on the in vitro activity of cefepime against gram-negative bacilli; Verbist L et al.; The in vitro activity of cefepime has been compared with that of cefotaxime, ceftazidime, aztreonam, and piperacillin against 1826 Enterobacteriaceae including 537 inducible Enterobacteriaceae (Enterobacter spp., Serratia spp., Citrobacter spp, . Morganella morganii) and 572 non-fermenters, including 401 Pseudomonas aeruginosa and 111 Acinebacter spp . isolated from hospitalized patients in 28 Belgian hospitals . Overall, cefepime was found substantially more active than the third-generation cephalosporins, aztreonam and piperacillin against Enterobacteriaceae species producing inducible type I cephalosporinases . Notably, cefepime remained active against 96% of Enterobacteriaceae resistant to cefotaxime, ceftazidime or aztreonam while it displayed a similar activity against E . coli and the other Enterobacteriaceae . Against non-fermenters, cefepime was found less active than ceftazidime but more than cefotaxime or aztreonam. Arch Surg, 1996 Jan, 131(1), 95 - 7 Aerobic and anaerobic microbiology of superficial suppurative thrombophlebitis; Brook I et al.; OBJECTIVE: To study the aerobic and anaerobic microbiologic characteristics of superficial suppurative thrombophlebitis . DESIGN: Retrospective review of microbiologic and clinical data . SETTING: Navy Hospital in Bethesda, Md . RESULTS: Sixty-one isolates, 36 aerobic and 25 anaerobic, were isolated from samples obtained from 42 patients . Aerobic bacteria only were found in 26 (62%) patients; anaerobic only, in 11 (26%); and mixed aerobic and anaerobic bacteria, in five (12%) . The predominant aerobic bacteria were Staphylococcus aureus (n = 9), Escherichia coli (n = 7), Pseudomonas aeruginosa (n = 4), and Klebsiella sp (n = 3) . The most frequently recovered anaerobic bacteria were Peptostreptococcus sp (n = 8), Propionibacterium acnes (n = 6), Bacteroides fragilis group (n = 5), Prevotella intermedia (n = 3), and Fusobacterium nucleatum (n = 3) . Propionibacterium acnes and Peptostreptococcus sp were associated with cannula-related superficial suppurative thrombophlebitis; B fragilis and Enterobacteriaceae, with abdominal surgery or pathology; and S aureus and P aeruginosa and Citrobacter sp, with burns . CONCLUSION: These data illustrate the importance of anaerobic bacteria in superficial suppurative thrombophlebitis. Mol Gen Genet, 1995 Dec 15, 249(5), 474 - 86 SlyA, a regulatory protein from Salmonella typhimurium, induces a haemolytic and pore-forming protein in Escherichia coli; Ludwig A et al.; A chromosomal fragment from Salmonella typhimurium, when cloned in Escherichia coli, generates a haemolytic phenotype . This fragment carries two genes, termed slyA and slyB . The expression of slyA is sufficient for the haemolytic phenotype . The haemolytic activity of E . coli carrying multiple copies of slyA is found mainly in the cytoplasm, with some in the periplasm of cells grown to stationary phase, but overexpression of SlyB, a 15 kDa lipoprotein probably located in the outer membrane, may lead to enhanced, albeit unspecific, release of the haemolytic activity into the medium . Polyclonal antibodies raised against a purified SlyA-HlyA fusion protein identified the overexpressed monomeric 17 kDa SlyA protein mainly in the cytoplasm of E . coli grown to stationary phase, although smaller amounts were also found in the periplasm and even in the culture supernatant . However, the anti-SlyA antibodies reacted with the SlyA protein in a periplasmic fraction that did not contain the haemolytic activity . Conversely, the periplasmic fraction exhibiting haemolytic activity did not contain the 17 kDa SlyA protein . Furthermore, S . typhimurium transformed with multiple copies of the slyA gene did not show a haemolytic phenotype when grown in rich culture media, although the SlyA protein was expressed in amounts similar to those in the recombinant E . coli strain . These results indicate that SlyA is not itself a cytolysin but rather induces in E . coli (but not in S . typhimurium) the synthesis of an uncharacterised, haemolytically active protein which forms pores with a diameter of about 2.6 nm in an artificial lipid bilayer . The SlyA protein thus seems to represent a regulation factor in Salmonella, as is also suggested by the similarity of the SlyA protein to some other bacterial regulatory proteins . slyA- and slyB-related genes were also obtained by PCR from E . coli, Shigella sp . and Citrobacter diversus but not from several other gram-negative bacteria tested. Am J Infect Control, 1995 Dec, 23(6), 357 - 63 Polymicrobial gram-negative bacteremia associated with saline solution flush used with a needleless intravenous system; Chodoff A et al.; BACKGROUND: During a 2-week period, seven cases of nosocomial polymicrobial gram-negative rod bacteremia occurred on a 39-bed medical and cardiac step-down unit . Combinations of Enterobacter cloacae (seven isolates), Klebsiella pneumoniae (five isolates), and Citrobacter freundii (two isolates) were isolated from blood cultures . METHODS: Concurrent and retrospective chart reviews were used to look for further cases and common exposures . Epidemiologic methods were used to refine determination of common exposure . Restriction enzyme DNA analysis was performed on the isolates . RESULTS: Concurrent and retrospective chart reviews revealed four additional possible cases during the same period . All case patients were exposed, through peripheral saline solution locks or central venous catheters, to saline solution "flush" from a central 0.9% saline solution bag and a needleless dispensing pin . Epidemiologic methods implicated probable extrinsic contamination of a single bag and pin used during a 24-48-hour period (Fisher's Exact Test, p < 0.002) . There were no other common exposures . Restriction enzyme DNA analysis of the isolates further supported a common source for the outbreak . CONCLUSIONS: The introduction of needleless intravascular systems has been embraced for employee protection . Our report is the first to raise the question of patient safety with such systems . This outbreak highlights the inherent risks in rapid introduction of new technologies and points out the delicate balance among patient health, employee safety, and cost containment. J Chemother, 1995 Dec, 7(6), 509 - 14 Antimicrobial resistance and prevalence of extended spectrum beta-lactamase among clinical isolates of gram-negative bacteria in Riyadh; El-Karsh T et al.; The activity of ciprofloxacin, imipenem and 12 other commonly used antibiotics was evaluated against 106 documented clinical isolates from a medical Intensive Care Unit (ICU) . The resistance rates to ceftriaxone, cefotaxime, aztreonam and ceftazidime were 42, 25, 24 and 21%, respectively . Apart from Pseudomonas aeruginosa, all isolates were sensitive to ciprofloxacin and imipenem . Complete cross resistance among tested beta-lactam groups was uniformly evident in Enterobacter cloacae, Citrobacter freundii and P . aeruginosa . On the other hand, penicillins and second generation cephalosporins showed cross resistance among Escherichia coli and Klebseilla pneumoniae isolates . Induction experiments indicate that 70 and 62% of P . aeruginosa and E . cloacae or C . freundii produce class I cephalosporinase, respectively . Among all tested isolates, plasmid mediated extended spectrum beta-lactamase (ESBL) was detected in one isolate of K . pneumoniae . The plasmid mediated beta-lactamase is transferable and inhibited by beta-lactamase inhibitors . The transconjugates not only expressed resistance to extended spectrum beta-lactams and aztreonam but also toward tested aminoglycoside antibiotics, with the exception of gentamicin . The obtained transconjugates conferred high level resistance to ceftazidime and aztreonam but considerably low resistance to ceftriaxone and cefotaxime . The isoelectric point for the extended-spectrum beta-lactamase is 8.2. Antimicrob Agents Chemother, 1995 Dec, 39(12), 2787 - 91 In vitro antibacterial properties of T-5575 and T-5578 novel parenteral 2-carboxypenams; Watanabe Y et al.; T-5575 and T-5578, novel 2-carboxypenams in which a carboxyl group has been introduced into the C-2 beta position of the nucleus, were evaluated for their in vitro antibacterial properties . The spectrum of activity of T-5575 was similar to that of aztreonam . However, it showed stronger activities than those of aztreonam against most gram-negative bacteria . T-5575 also showed potent activities against isolates of Enterobacter cloacae, Citrobacter freundii, and Pseudomonas aeruginosa resistant to ceftazidime, with MICs at which 90% of the isolates were inhibited of 0.39, 0.39, and 3.13 microgram/ml, respectively . T-5578 showed moderate levels of activity against gram-negative bacteria, compared with those of T-5575 . Its activity against P . aeruginosa, however, was superior to those of T-5575 and the reference drugs tested . The most characteristic feature of T-5578 was its potent activities against ceftazidime-, imipenem-, and gentamicin-resistant P . aeruginosa isolates, with MICs at which 90% of the isolates were inhibited at 0.39, 3.13, and 3.13 microgram/ml, respectively . These two compounds were unfortunately poorly active against gram-positive bacteria, such as Staphylococcus aureus and streptococci . Both compounds were found to be stable for hydrolysis by various kinds of beta-lactamases and to have low affinities for these enzymes, with Ki values of > 100 microM . These novel penams bound most tightly to penicillin-binding protein 3 of Escherichia coli and P . aeruginosa . These results indicate that T-5575 and T-5578 can be regarded as promising 2-carboxypenams specially targeted against gram-negative pathogens. Jpn J Antibiot, 1995 Dec, 48(12), 1906 - 19 {Antimicrobial activities of cefepime against clinically isolated strains}; Suzuki Y et al.; In order to evaluate antimicrobial activity of cefepime (CFPM), minimum inhibitory concentrations (MICs) of CFPM and other drugs were determined against clinical isolates that were obtained in 1994 . 1 . CFPM showed a wide antibacterial spectrum against Staphylococcus spp . and glucose non-fermentative Gram-negative rods ((G)NF-GNR) . Antimicrobial activities of CFPM against Staphylococcus spp . were stronger than those of ceftazidime (CAZ) and somewhat stronger than those of cefotaxime (CTX), and antimicrobial activity of CFPM against Pseudomonas aeruginosa was same as that of CAZ . 2 . Antimicrobial activities of CFPM against almost all of Enterobacteriaceae were stronger than those of CAZ and CTX . And CFPM showed strong antimicrobial activities against CAZ-resistant Escherichia coli, Citrobacter freundii and Enterobacter spp . 3 . Antimicrobial activities of CFPM were weaker than those of CAZ against some of strains of Klebsiella oxytoca, beta-lactamase high producing strains of Moraxella subgenus Branhamella catarrhalis and than those of CTX against beta-lactamase high producing strains of Prevotella spp . 4 . The feature of new cephems was demonstrated in that CFPM had wider antibacterial spectrum than cephems of previous genenations against Staphylococcus spp . and (G)NF-GNR and CFPM showed strong antimicrobial activities against almost all of oxacephem-resistant Enterobacteriaceae. J Appl Bacteriol, 1995 Dec, 79(6), 635 - 9 Detection of Escherichia coli in potable water using direct impedance technology; Colquhoun KO et al.; Direct impedance measurement utilizing a medium previously described as being specific for Escherichia coli and which contains trimethylamine N-oxide (TMAO) and glucuronic acid was used to detect E . coli in water samples . The system was compared with the Colilert presence/absence test and the United Kingdom standard membrane filtration technique using membrane lauryl sulphate broth . The impedance method correlated well with both the traditional membrane method (93%) and the Colilert method (93.95%) for a number of different water types . No interference from Citrobacter spp . (as reported in previous studies) was detected in this study although some Salmonella spp . did give false-positive results . The data presented here suggest that the use of direct impedance may offer an alternative to conventional methods for the detection of E . coli in water. Clin Infect Dis, 1995 Nov, 21(5), 1107 - 13 The relationship between antecedent antibiotic use and resistance to extended-spectrum cephalosporins in group I beta-lactamase-producing organisms; Jacobson KL et al.; Gram-negative pathogens are increasingly resistant to extended-spectrum cephalosporins (ESCs) . Using a prospective, case-controlled observational study, we examined the prevalence and the risk factors for development of resistance to ESCs in group I beta-lactamase-producing organisms . Of the 386 isolates of Enterobacter species, Pseudomonas aeruginosa, Citrobacter species, and Serratia marsescens from 340 consecutive patients, 70 (18.1%) were resistant to ESCs; the highest rates of resistance were found among Citrobacter freundii (40.9%), Enterobacter cloacae (31.1%), and Enterobacter aerogenes isolates (18.9%) . Patients' prior antibiotic use and the mean number of antibiotics used were significantly greater in association with resistant vs . susceptible isolates . Resistance was associated with prior use of ceftizoxime or cefotaxime (P = .008), ceftazidime (P = .004), and piperacillin (P = .001) . Other antibiotics were not associated with resistance . Resistance was less frequent in patients receiving ESCs and an aminoglycoside . We conclude that prior use of ESCs is associated with the isolation of resistant group I beta-lactamase-producing organisms . Concomitant use of an aminoglycoside may decrease this risk. Antimicrob Agents Chemother, 1995 Nov, 39(11), 2494 - 8 DNA sequence differences of ampD mutants of Citrobacter freundii; Stapleton P et al.; Three groups of mutants with increased levels of beta-lactamase synthesis were selected from Citrobacter freundii 382010 by beta-lactam antibiotics at concentrations just above the MIC . Uninduced cultures of the hyperinducible group had 3- to 5-fold more beta-lactamase activity than the parent strain, with one mutant (termed type b) expressing 19 times the activity of the parent strain; the partially derepressed group had a relative 55-fold increase, while fully derepressed strains exhibited a 460-fold increase . Upon induction by growth in the presence of cefoxitin (32 micrograms/ml) for 2 h, the hyperinducible and derepressed groups had similar relative beta-lactamase activities of 650 and 725, respectively . Induction of beta-lactamase activity from partially derepressed mutants resulted in a relative activity of only 240 . The ampD gene including its promoter region was amplified from the parent strain and the mutant strains by PCR . The sequence of ampD from the parent strain showed only three nucleotide changes from a previously published sequence, none of which resulted in a change to the deduced amino acid sequence . Hyperinducible mutant strains of type a had an amino acid change of either a tryptophan in codon 95 to an arginine (Trp-95-->Arg) (three mutants) or Ala-158-->Asp (one mutant) . The hyperinducible type b strain had the change Tyr-102-->Asp . The derepressed strains had the following changes: Val-33-->Gly (one mutant), Asp-164-->Glu (one mutant), and Trp-95-->termination codon (two mutants) . We infer that the amino acid changes in the hyperinducible mutants result in altered AmpD activity, whereas, in contrast, they lead to an inactive protein in derepressed mutants . No nucleotide differences were found in the ampD gene from partially derepressed strains. FEMS Microbiol Lett, 1995 Nov 1, 133(1-2), 35 - 9 Cloning and nucleotide sequence of a gene upstream of the eaeA gene of enterohemorrhagic Escherichia coli O157:H7; Zhao S et al.; A DNA segment located immediately upstream of the eaeA gene of enterohemorrhagic Escherichia coli O157:H7 strain HA1 was cloned and sequenced . This segment contained an open reading frame encoding a predicted protein of 156 amino acids . A database search identified similar open reading frames upstream of the eaeA gene in two other bacterial pathogens, i.e . enteropathogenic E . coli and Citrobacter freundii . The predicted amino acid sequence of the enterohemorrhagic E . coli protein shared 96.8% and 94.2% identity with the enteropathogenic E . coli and C . freundii sequences, respectively . Because the open reading frame is located within the locus of enterocyte effacement region of the E . coli chromosome, a 'hot spot' for insertion of virulence factor genes, and shares high sequence homology with attaching and effacing EPEC and C . freundii, this protein may be associated with pathogenicity of E . coli O157:H7. Infect Control Hosp Epidemiol, 1995 Oct, 16(10), 564 - 9 Vertical transmission of Citrobacter diversus documented by DNA fingerprinting; Harvey BS et al.; OBJECTIVE: To confirm the vertical transmission of Citrobacter diversus from a mother to her infant and to evaluate the epidemiologic usefulness of a new automated procedure for analysis of polymerase chain reaction (PCR)-generated DNA fingerprints . DESIGN: Repetitive element-based PCR (rep-PCR) analysis of C diversus isolates from the blood and amniotic fluid of a mother and the blood of her infant was performed . Unrelated C diversus isolates also were characterized and compared with the isolates from mother and infant . DNA fingerprints were generated by gel electrophoresis of PCR products derived from either unlabeled standard repetitive sequence-based oligonucleotide primers or fluorescent primers . The standard rep-PCR fingerprints were analyzed by visual inspection . The fluorescent primers were used in fluorophore-enhanced rep-PCR (FERP), and the FERP DNA fingerprints were analyzed by an Applied BioSystems (ABI) Model 373A laser scanning unit equipped with Genescan 672 software (Applied Biosystems, Inc, Foster City, CA) . SETTING AND PATIENTS: A mother and her newborn infant, both with invasive disease due to C diversus, in an urban tertiary-care hospital . RESULTS: The DNA fingerprints of the maternal blood, amniotic fluid, and infant blood isolates of C diversus were identical by both visual inspection of ethidium bromide-stained agarose gels and computer-aided analysis of FERP patterns . These strains appeared to differ from all but one control isolate, which had been collected 7 years earlier in the same city in which the infant was born . CONCLUSIONS: Vertical transmission of C diversus from mother to infant can occur in utero . Automated analysis of rep-PCR-generated DNA fingerprints derived using fluorescent primers is an objective means for comparing isolates of C diversus and in all likelihood would be useful for other species of bacteria that possess repetitive elements. Microbiology, 1995 Oct, 141 ( Pt 10), 2433 - 41 Phosphatase production and activity in Citrobacter freundii and a naturally occurring, heavy-metal-accumulating Citrobacter sp; Montgomery DM et al.; The ability of a naturally occurring Citrobacter sp . to accumulate cadmium has been attributed to cellular precipitation of CdHPO4, utilizing HPO4(2-) liberated via the activity of an overproduced, Cd-resistant acid-type phosphatase . Phosphatase production and heavy metal accumulation by batch cultures of this strain (N14) and a phosphatase-deficient mutant were compared with two reference strains of Citrobacter freundii . Only strain N14 expressed a high level of acid phosphatase and accumulated lanthanum and uranyl ion enzymically . Acid phosphatase is regulated via carbon-starvation; although the C . freundii strains overexpressed phosphatase activity in carbon-limiting continuous culture, this was approximately 20-fold less than the activity of strain N14 grown similarly . Citrobacter strain N14 was originally isolated from a metal-contaminated soil environment; phosphatase overproduction and metal accumulation were postulated as a detoxification mechanism . However, application of Cd-stress, and enrichment for Cd-resistant C . freundii ('training'), reduced the phosphatase activity of this organism by about 50% as compared to Cd-unstressed cultures . The acid phosphatase of C . freundii and Citrobacter N14 had a similar pattern of resistance to some diagnostic reagents . The enzyme of the latter is similar to the PhoN acid phosphatase of Salmonella typhimurium described by other workers; the results are discussed with respect to the known phosphatases of the enterobacteria. Lett Appl Microbiol, 1995 Oct, 21(4), 249 - 51 A comparison of immunomagnetic separation plus enrichment with conventional Salmonella culture in the examination of raw sausages; Coleman DJ et al.; Immunomagnetic separation with additional enrichment was used in conjunction with improved selective media to improve the isolation of salmonellae from raw sausages . The isolation rate achieved was almost double that of conventional culture with no increase in processing time . The selective media gave an overall specificity of approximately 74%; all false-positive pickoffs being identified as Citrobacter freundii . It is believed that this method represents a significant advance in the isolation of salmonellae from foods, although the ideal media both for enrichment and selection have yet to be found. Biochemistry, 1995 Sep 26, 34(38), 12276 - 83 Site-directed mutagenesis of tyrosine-71 to phenylalanine in Citrobacter freundii tyrosine phenol-lyase: evidence for dual roles of tyrosine-71 as a general acid catalyst in the reaction mechanism and in cofactor binding; Chen HY et al.; Tyr71 is an invariant residue in all known sequences of tyrosine phenol-lyase (TPL) . The substitution of Tyr71 in TPL by phenylalanine results in a mutant Y71F TPL with no detectable activity (greater than 3 x 10(5)-fold reduction) for beta-elimination of L-tyrosine . Y71F TPL can react with S-alkylcysteines, but these substrates exhibit kcat values reduced by 10(3)-10(4)-fold, while the kcat/Km values are reduced by 10(2)-10(3)-fold, compared to wild-type TPL . However, for substrates with good leaving groups (S-(o-nitrophenyl)-L-cysteine,beta-chloro-L-alanine, and O-benzoyl-L-serine), Y71F TPL exhibits kcat values 1.85-7% those of wild-type TPL . Y71F TPL forms very stable quinonoid complexes with strong absorbance at 502 nm from L-phenylalanine, tyrosines (L-tyrosine, 3-fluoro-L-tyrosine, and {alpha-2H}-3-fluoro-L-tyrosine), and S-alkylcysteines (S-methyl-L-cysteine, S-ethyl-L-cysteine, and S-benzyl-L-cysteine) . The time courses of the formation of quinonoid intermediates in these reactions are biphasic . The slow phase shows a dependence on concentration of PLP and is due to the cofactor binding steps, while the fast phase is due to the amino acid alpha-deprotonation and reprotonation steps . The rate constants for the fast phase of the reactions of Y71F TPL with L-phenylalanine and S-methylcysteine are similar to those for alpha-deprotonation or reprotonation steps in the reactions of wild-type TPL . The PLP binding constant of Y71F TPL is estimated to be 1 mM by spectrophotometric titration, compared to 0.6 microM for wild-type TPL.(ABSTRACT TRUNCATED AT 250 WORDS) J Antimicrob Chemother, 1995 Sep, 36(3), 537 - 43 Escherichia hermannii: susceptibility pattern to beta-lactams and production of beta-lactamase; Fitoussi F et al.; The susceptibility pattern of Escherichia hermannii, although closely related to Escherichia coli according to its biochemical patterns, was clearly distinguishable by its susceptibility to beta-lactams by both diffusion and dilution methods from E . coli penicillinase producing or non-producing strains, Citrobacter diversus, Klebsiella pneumoniae, and Klebsiella oxytoca . Beta-lactamase clavulanate-sensitive activity was localized with various isoelectric points from 7.0 to 8.5 . No cross hybridization with DNA intragenic probes (blaTEM, blaSHV, blaCARB and blaOXY) was observed by dot blot procedure. J Antimicrob Chemother, 1995 Sep, 36(3), 483 - 96 The ability of beta-lactam antibiotics to select mutants with derepressed beta-lactamase synthesis from Citrobacter freundii; Stapleton P et al.; The ability of beta-lactam compounds to induce synthesis of the class C beta-lactamase of Citrobacter freundii was assessed both directly and indirectly, the latter by measurement of the different susceptibilities of strains with inducible and depressed beta-lactamase synthesis and those of a beta-lactamase-negative strain . Most beta-lactam compounds were poor inducers but ampicillin, amoxycillin and cephalexin were moderately good inducers and cefoxitin, imipenem and meropenem were strong inducers . The ability of the compounds to select mutants in which the synthesis of the beta-lactamase was derepressed was also assessed . Imipenem and temocillin, which had a high degree of stability to the beta-lactamase failed to select such mutants or were very poor selectors . In contrast, most other compounds showed considerable lability to the beta-lactamase and readily selected derepressed mutants, whether they were strong inducers of beta-lactamase synthesis (for example cefoxitin) or poor inducers (cefotaxime, ceftazidime and many other compounds) . Thus it appears that lability to the beta-lactamase is a more important factor in determining whether or not a compound will select derepressed mutants than the power of the compound as an inducer of beta-lactamase synthesis, since induction results in the production of less beta-lactamase than derepression as a result of mutation. Lijec Vjesn, 1995 Sep-Oct, 117(9-10), 249 - 53 {Clinical and laboratory significance of inducible beta-lactamases}; Bedenic B et al.; Many species of bacteria have inducible expression of beta-lactamase and the enzyme production in these bacteria is normally held at a low level by a repressor mechanism, but in the presence of a beta-lactamase inducer this repression is lifted and enzyme production is greatly increased . Inducible synthesis of beta-lactamase was first described for the gram-positive organism Bacillus licheniformis . After that inducible expression of beta-lactamase was discovered in gram-negative bacteria like Enterobacter cloacae, Citrobacter freundii, Pseudomonas aeruginosa, Morganella morganii, Proteus vulgaris, Serratia spp and Aeromonas spp . Inducible beta-lactamases belong into class I according to Richmond and Sykes . They are chromosomally mediated cephalosporinases . beta-lactam antibiotics differ in their inducing power . Cefoxitin and imipenem are among the strongest inducers . Induction of beta-lactamase caused by these substances can lead to antagonism with other beta-lactam antibiotics if they are used in combination . The most important clinical problem connected with inducible beta-lactamases is the emergence of multiple resistant strains which are associated with therapeutic failures . It is important to distinguish induction from derepression . Induction is a temporary phenomenon in which an inducer interacts with a functional AmpD protein, which consequently prevents complexing of the AmpD and ampR proteins . In contrast, genetic derepression is permanent and results from synthesis of a defective AmpD protein unable to complex with the AmpR protein. J Bacteriol, 1995 Sep, 177(18), 5379 - 80 Cloning, sequencing, and expression of the araE gene of Klebsiella oxytoca 8017, which encodes arabinose-H+ symport activity; Shatwell KP et al.; Southern analysis of the genomic DNA from species of the family Enterobacteriaceae, using a probe derived from the Escherichia coli araE gene, which encodes an arabinose-H+ symporter, detected araE in Salmonella, Citrobacter, Klebsiella, and Enterobacter spp . The Klebsiella oxytoca araE gene was cloned, sequenced, and expressed to compare its properties with those of araE from E . coli. J Antibiot (Tokyo), 1995 Sep, 48(9), 1027 - 33 Effects of tazobactam on the frequency of the emergence of resistant strains from Enterobacter cloacae, Citrobacter freundii, and Proteus vulgaris (beta-lactamase derepressed mutants); Higashitani F et al.; When Enterobacter cloacae, Citrobacter freundii, and Proteus vulgaris were treated with piperacillin (PIPC) in combination with tazobactam (TAZ), the in vitro frequency of emergence of resistant strains (beta-lactamase producing mutants) was lower than with PIPC or ceftazidime (CAZ) treated bacteria . In a mouse intraperitoneal infection model caused by E . cloacae, beta-lactamase derepressed mutants were detected following therapy with PIPC or CAZ, although no derepressed mutants were detected after treatment with PIPC in combination with TAZ . This suppression of the selection of derepressed mutants, which produce large amounts of beta-lactamases, by the combination of TAZ and PIPC suggests that the combination delays the increase of resistant mutants compared with PIPC alone. Jpn J Antibiot, 1995 Sep, 48(9), 1174 - 263 {Comparative studies on activities of antimicrobial agents against causative organisms isolated from urinary tract infections (1989) . III . Secular changes in susceptibility}; Kumamoto Y et al.; Susceptibilities of Citrobacter spp., Enterobacter spp., Escherichia coli, Klebsiella spp., Proteus mirabilis, Pseudomonas aeruginosa, Serratia spp . isolated from patients with urinary tract infections (UTIs) in 10 hospitals during June 1989 to May 1990 to various antimicrobial agents were compared with those in the same period of previous years according to a classification, uncomplicated UTIs, complicated UTIs without indwelling catheter, and complicated UTIs with indwelling catheter . As for Citrobacter spp., P . mirabilis and Serratia spp., which were detected very few in 1989, their susceptibilities were not observed an obvious change . As for Enterobacter spp., the susceptible strains to flomoxef, cefixime, cefuzonam and ceftazidime increased in complicated UTIs with indwelling catheter . The susceptibilities of E . coli to penicillins increased slightly in complicated UTIs with indwelling catheter . Against Klebsiella spp., a good activity of minocycline or cephems was found . The susceptibilities of P . aeruginosa to ciprofloxacin and new quinolones increased in uncomplicated UTIs . These data should be considered in clinical treatment of various urinary tract infections. Epidemiol Infect, 1995 Aug, 115(1), 61 - 70 Control of infection with multiple antibiotic resistant bacteria in a hospital renal unit: the value of plasmid characterization; Reed CS et al.; An outbreak of infections due to multiple antibiotic-resistant bacteria took place over a period of approximately 18 months in a renal unit . Strains of Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Citrobacter spp . and Pseudomonas spp . were involved, and a variety of antibiotic resistances was encountered . Closely related plasmids encoding resistance to aztreonam, ceftazidime and piperacillin, possibly derived from an archetypal plasmid of 105 kb were found in the majority of isolates examined . After limiting the use of aztreonam the incidence of new patient isolates of multiple-resistant organisms was greatly reduced . This study demonstrated how molecular studies can contribute to the control of an outbreak situation in a hospital unit by providing an impetus to reduce the use of specific antibiotics. J Bacteriol, 1995 Aug, 177(15), 4392 - 401 Biochemical and molecular characterization of the oxidative branch of glycerol utilization by Citrobacter freundii; Daniel R et al.; Glycerol dehydrogenase (EC 1.1.1.6) and dihydroxyacetone kinase (EC 2.7.1.29) were purified from Citrobacter freundii . The dehydrogenase is a hexamer of a polypeptide of 43,000 Da . The enzyme exhibited a rather broad substrate specificity, but glycerol was the preferred substrate in the physiological direction . The apparent Kms of the enzyme for glycerol and NAD+ were 1.27 mM and 57 microM, respectively . The kinase is a dimer of a polypeptide of 57,000 Da . The enzyme was highly specific for the substrates dihydroxyacetone and ATP; the apparent Kms were 30 and 70 microM, respectively . The DNA region which contained the genes encoding glycerol dehydrogenase (dhaD) and dihydroxyacetone kinase (dhaK) was cloned and sequenced . Both genes were identified by N-terminal sequence comparison . The deduced dhaD gene product (365 amino acids) exhibited high degrees of homology to glycerol dehydrogenases from other organisms and less homology to type III alcohol dehydrogenases, whereas the dhaK gene product (552 amino acids) revealed no significant homology to any other protein in the databases . A large gene (dhaR) of 1,929 bp was found downstream from dhaD . The deduced gene product (641 amino acids) showed significant similarities to members of the sigma 54 bacterial enhancer-binding protein family. J Clin Microbiol, 1995 Aug, 33(8), 2064 - 8 Genetic and biochemical characterization of Citrobacter rodentium sp . nov; Schauer DB et al.; An unusual bacterial pathogen of laboratory mice has been previously classified as an atypical biotype of Citrobacter freundii . Designated C . freundii biotype 4280, this bacterium is the etiologic agent of transmissible murine clonic hyperplasia . An eaeA gene has been shown to be present in this organism and to be necessary for virulence in laboratory mice . However, other biotypes of C . freundii lack DNA homology with the eaeA gene . Because of the recent reclassification in which five named species and three unnamed species, all previously considered C . freundii, were described, we determined the taxonomic status of C . freundii biotype 4280 . With a battery of biochemical tests and DNA relatedness studies, three isolates of C . freundii biotype 4280 were shown to be members of an unnamed Citrobacter species, designated species 9 . In total, six isolates of Citrobacter species 9, but none of the type strains of the other eight named species or of the two remaining unnamed species of Citrobacter, were shown to possess DNA homology with both the eaeA and the eaeB genes . Species 9 was named Citrobacter rodentium sp . nov. Diagn Microbiol Infect Dis, 1995 Jul, 22(3), 261 - 6 Beta-D-Glucuronidase activity among prototrophic and auxotrophic variants of Escherichia coli and other Enterobacteriaceae commonly implicated in urinary tract infections; Tapsall JW et al.; Glucuronidase (GUD) activity of 102 prototrophic, 91 cysteine-requiring, and 19 thymidine-requiring strains of Escherichia coli was examined using growth from MacConkey, CLED, and enriched brain heart infusion (BHI) agars . After 24 h incubation, GUD activity was detected in 92%-96% of prototrophic strains and a similar proportion of thymidine-requiring strains with most reactions detectable in shorter incubation periods . GUD activity among strains requiring cysteine was significantly less than that found amongst prototrophic strains . The effects of different sources of inocula were evident in the shorter incubation periods . Other strains of the Enterobacteriaceae and oxidative strains frequently implicated in urinary tract infection were also tested . Here, positive reactions were detected among Citrobacter and Enterobacter spp . and a strain of Klebsiella oxytoca, but only after 24 h incubation . GUD activity was not detected among the oxidative strains tested under the same conditions . Although an incubation time of 24 h is necessary to detect activity in a small number of "slow hydrolyzing" E . coli, the increased sensitivity thus attained compromises the specificity of the test for this organism by simultaneously enhancing detection of the enzyme in other enterobacteria. Pediatr Infect Dis J, 1995 Jul, 14(7 Suppl), S77 - 83 Ceftibuten: a review of antimicrobial activity, spectrum and other microbiologic features; Jones RN; Ceftibuten is a new, orally administered cephalosporin with exceptional beta-lactamase stability and potency against commonly isolated Gram-negative pathogens . More than 90% of recent Enterobacteriaceae clinical isolates were inhibited by < or = 8 micrograms/ml of ceftibuten . In only five enteric species (Citrobacter freundii, Enterobacter aerogenes, Enterobacter cloacae, Morganella morganii, Serratia marcescens) were more than 15% of strains resistant (minimal inhibitory concentrations (MIC, with percent of strains inhibited in subscript numbers) > 16 micrograms/ml) to ceftibuten . Enteritis-producing bacteria such as Salmonella, Shigella, Escherichia coli and Yersinia were very ceftibuten-susceptible (MIC50 < or = 0.13 microgram/ml) . Fastidious Gram-negative species causing respiratory tract or genital infections had very low ceftibuten MICs, including beta-lactamase-positive Haemophilus influenzae (MIC90 0.06 to 2 micrograms/ml), Moraxella catarrhalis (MIC90 0.25 to 4 micrograms/ml), and Neisseria gonorrhoeae (MIC90 0.015 to 0.5 microgram/ml) . Beta-hemolytic streptococci and penicillin-susceptible pneumococci were also inhibited by ceftibuten . Staphylococci, enterococci, Pseudomonas species and Gram-negative anaerobic bacteria were generally resistant to ceftibuten . Ceftibuten has demonstrated bactericidal activity against susceptible pathogens, has high affinity for several lethal penicillin-binding proteins and possesses stability to common plasmid- or chromosomal-mediated beta-lactamases, including those enzymes that hydrolyze parenteral third generation cephalosporins . The microbiologic features for ceftibuten indicate its clinical potential as chemotherapy for community-acquired respiratory tract infections. J Chemother, 1995 Jun, 7 Suppl 2, 31 - 44 The changing nature of aminoglycoside resistance mechanisms and the role of isepamicin--a new broad-spectrum aminoglycoside . The Aminoglycoside Resistance Study Groups; Miller GH et al.; Aminoglycoside resistance mechanisms from recent studies were compared with those found in earlier studies in the USA and Europe for three pathogen groups . Among Citrobacter-Enterobacter-Klebsiella, four single mechanisms (AAc(3)-II, AAC(3)-I, ANT(2")-I and AAC(6')-I were found in all studies, but the most recent studies showed a significant increase in combinations of AAC(6')-I with the other common mechanisms . Since AAC(6')-I confers resistance to tobramycin, netilmicin and amikacin, combinations of it with the other gentamicin modifying enzymes conferred broad-spectrum resistance to all clinically available aminoglycosides except isepamicin . Similar changes occurred in Escherichia-Morganella-Proteus-Salmonella-Shigella except that the frequency of combinations was much lower and two additional single mechanisms - AAC(3)-IV and permeability - were also found frequently . Among aminoglycoside-resistant Pseudomonas, three mechanisms, AAC(6')-II, ANT(2")-I and permeability, were always common and remained common . However, combinations of the three mechanisms with each other and with other mechanisms were more common in the recent surveys . Different genes which produce different proteins with the same aminoglycoside-modifying activity are now known . The results of hybridisation studies with two aac(3)-I, 2 aac(6')-II and 4 aac(6')-I gene probes are presented . The most commonly occurring genes were: aac(3)-Ia, aac(3)-IIa, aac(6')-IIa, aac(6')-Ib and, in Serratia, aac(6')-Ic . The activity of isepamicin against amikacin resistant strain which produce AAC(6')-I can be related to differences in the structure of these two similar aminoglycosides at Position 3" . Amikacin may form a stable complex with AAC(6')-I enzymes via binding interaction at Position 3 and 3" . Isepamicin, which has a secondary amino group at Position 3", may only be able to interact at Position 3 and enzyme-isepamicin complexes are likely to be less stable. Appl Environ Microbiol, 1995 Jun, 61(6), 2335 - 40 Effect of oxytetracycline-medicated feed on antibiotic resistance of gram-negative bacteria in catfish ponds; DePaola A et al.; The effect of oxytetracycline-medicated feeds on antibiotic resistance in gram-negative bacteria from fish intestines and water in catfish ponds was investigated . In experiments in the fall and spring, using ponds with no previous history of antibiotic usage, percentages of tetracycline-resistant bacteria in catfish intestines obtained from medicated ponds increased significantly after 10 days of treatment . In the fall, resistance of the intestinal and aquatic bacteria returned to pretreatment levels within 21 days after treatment . In the spring, resistance declined after treatment but remained higher than pretreatment levels for at least 21 days in intestinal bacteria and for 5 months in aquatic bacteria . Plesiomonas shigelloides, Aeromonas hydrophila, and Citrobacter freundii were isolated frequently in both spring and fall; Escherichia coli, Klebsiella pneumoniae, Edwardsiella tarda, and Enterobacter spp . were isolated primarily in the spring . Oxytetracycline treatment did not affect the distribution of bacterial species in the fall but may have accelerated a shift toward greater prevalence of members of the family Enterobacteriaceae in the spring . Multiple antibiotic resistance did not appear to be elicited by oxytetracycline treatment. Epidemiol Infect, 1995 Jun, 114(3), 441 - 50 Verotoxinogenic Citrobacter freundii associated with severe gastroenteritis and cases of haemolytic uraemic syndrome in a nursery school: green butter as the infection source; Tschape H et al.; A summer outbreak of severe gastroenteritis followed by haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopenic purpura in a nursery school and kindergarten is described . Sandwiches prepared with green butter made with contaminated parsley were the likely vehicle of infection . The parsley originated from an organic garden in which manure of pig origin was used instead of artificial fertilizers . Clonally identical verotoxinogenic Citrobacter freundii were found as causative agents of HUS and gastroenteritis and were also detected on the parsley. Pediatrics, 1995 Jun, 95(6), 803 - 6 No lumbar puncture in the evaluation for early neonatal sepsis: will meningitis be missed? Wiswell TE, Baumgart S, Gannon CM, Spitzer AR. OBJECTIVE . We performed this investigation to assess whether selective approaches to performing lumbar puncture (LP) in the early neonatal period will result in a missed or delayed diagnosis of bacterial meningitis . DESIGN . A retrospective review was conducted of the medical records of all neonates born in US Army hospitals from 1988 through 1992 who developed culture-positive meningitis during the first 72 hours of life . RESULTS . In total, 169,849 infants were born during the 5-year study period . The incidence of meningitis in the first 72 hours of life was 0.25 per 1000 live births . Forty-three infants had organisms isolated from their cerebrospinal fluid (30, group B streptococcus; 10, Escherichia coli; 1, Listeria monocytogenes; 1, Streptococcus pneumoniae; and 1, Citrobacter diversus) . The median age of infants at evaluation was 12 hours, and the mean gestational age was 38.8 weeks (7 < 37 weeks), whereas mean birth weight was 3163 g (7 < 2500 g) . If we had used currently advocated selective criteria as the basis for not performing an LP, the diagnosis of bacterial meningitis would have been missed or delayed in 16 of 43 infants (37%): 5 infants born prematurely with suspected respiratory distress syndrome, 3 asymptomatic infants born at term with positive blood cultures, and 8 infants born at term with no central nervous system symptoms and negative blood cultures . CONCLUSIONS . If LPs are omitted as part of the early neonatal sepsis evaluation, the diagnosis of bacterial meningitis occasionally will be delayed or missed completely. Microbiology, 1995 May, 141 ( Pt 5), 1085 - 92 The signal transducer encoded by ampG is essential for induction of chromosomal AmpC beta-lactamase in Escherichia coli by beta-lactam antibiotics and 'unspecific' inducers; Schmidt H et al.; Chemical mutagenesis of the AmpC beta-lactamase-hyperinducible Escherichia coli strain SN0301/pNu305 carrying the cloned ampC and ampR genes from Citrobacter freundii OS60 gave four independent mutants in which beta-lactamase was no longer inducible, or was inducible only to a low level, by beta-lactam antibiotics . The genes ampC, ampR, ampD and ampE, which were essential for beta-lactamase induction, were functional in these mutants . In all four mutants, the sites of mutation were mapped to 9.9 min on the E . coli chromosome . Complementation with wild-type ampG restored inducibility of beta-lactamase to wild-type levels . The nucleotide sequence of all four mutant ampG alleles (ampG1, ampG3, ampG4 and ampG5) was determined . In three of the mutants, a single base exchange led to an amino acid change from glycine to aspartate at different sites in the deduced amino acid sequence . In the fourth mutant (ampG4), with low-level inducibility, the nucleotide sequence was identical to wild-type ampG . Spontaneous back-mutation of the chromosomal ampG1 mutant resulted in restoration of wild-type inducibility and a return to the wild-type ampG sequence . Unspecific induction by components of the growth medium was also dependent on intact ampG function. Epidemiol Mikrobiol Imunol, 1995 May, 44(2), 57 - 64 {Biochemical indicators of Citrobacter sedlakii}; Aldova E et al.; The authors describe eight strains identified biochemically as a new species of C . sedlakii in clinical material, surface water and the cutting surface of a melon . The majority of strains was isolated in the Czech and Slovak Republic. Res Microbiol, 1995 May, 146(4), 279 - 90 Taxonomic diversity of anaerobic glycerol dissimilation in the Enterobacteriaceae; Bouvet OM et al.; A total of 1,123 strains representing 128 taxa in the Enterobacteriaceae (named species or subspecies and genomic species) were screened for the presence of glycerol dehydrogenases and 1,3-propanediol dehydrogenase . Only eight taxa, Citrobacter freundii sensu stricto, C . youngae, C . braakii, C . werkmanii, Citrobacter genomospecies 10 and 11, Enterobacter gergoviae and Klebsiella pneumoniae subsp . pneumoniae could grow fermentatively on glycerol and possessed both glycerol dehydrogenase type I (induced by glycerol and dihydroxyacetone) and 1,3-propanediol dehydrogenase which are typical enzymes of the anaerobic glycerol dissimilation pathway . Six other species, C . koseri, E . aerogenes, E . intermedium, K . oxytoca, K . planticola and K . terrigena could not grow fermentatively on glycerol and possessed a glycerol dehydrogenase type I but no 1,3-propanediol dehydrogenase . Other glycerol dehydrogenases types were found: type II (induced by glycerol and hydroxyacetone), type III (induced by glycerol only) and type IV (induced by hydroxyacetone only) . They were widely distributed among the Enterobacteriaceae . Classification and identification may take advantage of tests exploring the dissimilation of glycerol. J Appl Bacteriol, 1995 May, 78(5), 507 - 20 Development and evaluation of two novel oligonucleotide probes based on 16S rRNA sequence for the identification of Salmonella in foods; Lin CK et al.; DNA sequence in the V3 to V6 region of the 16S rRNA gene of Salmonella enteritidis was determined . By comparison of this sequence with those of Escherichia coli and Proteus vulgaris obtained from GenBank/EMBL database, three oligonucleotides termed as 16S I, 16S II and 16S III were synthesized . Hybridization of these oligonucleotides with 325 Salmonella isolates and some non-Salmonella isolates including the Salmonella closely related species of the family of Enterobacteriaceae showed that 16S II could not be used as a Salmonella specific-probe . 16S I and 16S III hybridized with all the Salmonella isolates tested, the former also hybridizing with Citrobacter spp . and the latter hybridizing with Klebsiella pneumoniae as well as Serratia marcescens . Since enrichment of the target cells in food samples was usually required prior to the DNA hybridization assay, the interference from those non-Salmonella isolates could be prevented by enrichment by culturing in lactose-combined tetrathionate (CTET) broth followed by Gram-negative (GN) broth at 37 degrees C and/or 43 degrees C . Such a culture step could inhibit the growth of Klebsiella spp., Ser . marcescens and/or Citrobacter spp . and allowed the specific detection of Salmonella. Eur J Biochem, 1995 Apr 15, 229(2), 540 - 9 Site-directed mutagenesis of His343-->Ala in Citrobacter freundii tyrosine phenol-lyase . Effects on the kinetic mechanism and rate-determining step; Chen H et al.; His343 in Citrobacter freundii tyrosine phenol-lyase is conserved in all known sequences of both tyrosine phenol-lyase and tryptophan indole-lyase; it is located near the active-site Lys257 in C . freundii tyrosine phenol-lyase {Antson, A . A., Demidkina, T . V., Gollnick, P., Danter, Z., Von Tersch, R.L., Long, J., Berezhnoy, S . N., Phillips, R . S., Harutyunyan, E . H . & Wilson, K . S . (1993) Biochemistry 32, 4195--4206} . In order to evaluate the role of His343 in the reaction mechanism of tyrosine phenol-lyase and tryptophan indole-lyase, we have mutated it to Ala; the former mutant is referred to as {H343A}tyrosine phenol lyase . All substrates for alpha, beta-elimination (except S-ethyl-L-cysteine) exhibited lower kcat (10-30%) and kcat/Km (1-10%) values with {H343A}tyrosine phenol-lyase than with the wild-type enzyme . The mutant also shows slower rates of deuterium isotope exchange for L-phenylalanine and L-methionine than does the wild type . The pH-dependent behavior in the reaction of 3-fluoro-L-tyrosine with wild-type tyrosine phenol-lyase is identical to that of L-tyrosine described previously {Kiick, D . M . & Phillips, R . S . (1988) Biochemistry 27, 7333-7338} . The pH profile of kcat/Km for this reaction exhibits two pKa values with an average of 7.7 +/- 0.2, indicating that the catalytic mechanism requires two essential basic groups . The pH profile of kcat/Km for 3-fluoro-L-tyrosine with {H343A}tyrosine phenol-lyase also exhibits two pKa values with an average of 7.8 +/- 0.3 . However, kcat for 3-fluoro-L-tyrosine is pH-dependent for the mutant, exhibiting two pKa values with an average of about 7.8, whereas it is pH-independent for the wild type . Steady-state kinetic isotope effects on the reactions with wild-type and {H343A}tyrosine phenol-lyase were examined at various pH values . For the wild type, the values of the isotope effects on kcat and kcat/Km for 3-fluoro-L-{alpha-2H}-tyrosine are independent of pH and equal to 3.9 +/- 0.2 and 2.2 +/- 0.3, respectively, while the corresponding values for {H343A}tyrosine phenol-lyase are 5.4 +/- 0.2 and 3.8 +/- 0.3, respectively.(ABSTRACT TRUNCATED AT 400 WORDS) J Indian Med Assoc, 1995 Apr, 93(4), 132 - 5 Bacteria in surface infections of neonates; Ghosh S et al.; A bacteriological work on surface infections was done among live births (study group I) and neonates admitted in hospital (study group II) . Out of 134 cases of conjunctivitis in group I Gram-negative bacilli predominated (48.5%) with Escherichia coli accounting for 29 (14.9%) cases, Klebsiella species 15 (11.2%) cases, Citrobacter freundii 3 (2.2%) cases, Pseudomons aeruginosa 18 (13.4%) cases and Aeromonas hydrophila 3 (2.2%) amongst pure isolates (73.9%) . Gonococcus was noted in 2 (1.5%) cases . In group II, 41.7% were Staphylococcus aureus in pure growth (75%), compared to only 9.0% in group I . Skin infections were caused by both Staphylococcus aureus and Staphylococcus epidermidis . Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa were the principal insolates from umbilical sepsis . Pseudomonas aeruginosa was isolated as pure growth from local site of noma neonatorum . Anaerobic cultures were negative in all except in 2 cases of umbilical sepsis with tetanus neonatorum revealing Clostridium tetani which however proved to be non-toxigenic . Blood cultures were positive in 4 out of 14 cases bearing 50% correlation with bacteria from surface infections . A source study established partial correlation with the cases of pseudomonas conjunctivitis . Phage typing of Staphylococcus aureus and biochemical typing failed to detect any definite marker of clinical entities, except that the skin infections were caused by group III phages predominantly (65.0%). Eur J Biochem, 1995 Apr 1, 229(1), 299 - 307 Structural elucidation of the biological repeating unit of O-specific polysaccharide from Citrobacter serotype O41; Ravenscroft N et al.; Sugar analysis of the O-specific polysaccharide produced by Citrobacter serotype O41 revealed the presence of a hexasaccharide repeating unit, which includes the unusual 3-amino-N-(D-3'-hydroxybutyryl)-3,6-dideoxy-D-galactosyl residue (Fuc3NAcyl) . The structure of the repeating unit was determined by extensive use of homo- and heteronuclear two-dimensional NMR spectroscopy, including the application of long-range 1H-13C correlation experiments and NOE studies to establish the sequence of sugar units . Indentification of the Glc beta 1-->2Fuc3NAcyl beta 1-->6GlcNAc alpha 1-->sequence at the non-reducing terminus establishes the biological repeating unit of this O-specific polysaccharide as: -->2Glc beta 1-->Fuc3NAcyl-beta 1-->6GlcNAc alpha 1-->(Glc alpha 1-->2) 4Gal beta 1-->3GalNAc beta 1--> . This structure is similar to that found for the O-specific polysaccharide isolated from Hafnia alvei strain 1211 {Katzenellenbogen, E., Romanowska, E., Dabrowski, U . & Dabrowski, J . (1991) Eur . J . Biochem . 200, 401-407}, which differs in having an acetyl substituent at O4 of the Fuc3NAcyl residue and a branch point of GalNAc alpha substituted by Glc beta at O3; these differences are responsible for the only weak serological cross-reactivity of the two strains. J Bacteriol, 1995 Apr, 177(8), 2151 - 6 Purification of 1,3-propanediol dehydrogenase from Citrobacter freundii and cloning, sequencing, and overexpression of the corresponding gene in Escherichia coli; Daniel R et al.; 1,3-Propanediol dehydrogenase (EC 1.1.1.202) was purified to homogeneity from Citrobacter freundii grown anaerobically on glycerol in continuous culture . The enzyme is an octamer of a polypeptide of 43,400 Da . When tested as a dehydrogenase, the enzyme was most active with substrates containing two primary alcohol groups separated by one or two carbon atoms . In the physiological direction, 3-hydroxypropionaldehyde was the preferred substrate . The apparent Km values of the enzyme for 3-hydroxypropionaldehyde and NADH were 140 and 33 microM, respectively . The enzyme was inhibited by chelators of divalent cations but could be reactivated by the addition of Fe2+ . The dhaT gene, encoding the 1,3-propanediol dehydrogenase, was cloned, and its nucleotide sequence (1,164 bp) was determined . The deduced dhaT gene product (387 amino acids, 41,324 Da) showed a high level of similarity to a novel family (type III) of alcohol dehydrogenases . The dhaT gene was overexpressed in Escherichia coli 274-fold by using the T7 RNA polymerase/promoter system. Antimicrob Agents Chemother, 1995 Mar, 39(3), 629 - 37 Characterization of an LysR family protein, SmeR from Serratia marcescens S6, its effect on expression of the carbapenem-hydrolyzing beta-lactamase Sme-1, and comparison of this regulator with other beta-lactamase regulators; Naas T et al.; Serratia marcescens S6 produces a chromosomally encoded carbapenem-hydrolyzing class A beta-lactamase, Sme-1 (T . Naas, L . Vandel, W . Sougakoff, D . M . Livermore, and P . Nordmann, Antimicrob . Agents Chemother . 38:1262-1270, 1994) . Upstream from smeA we identified a second open reading frame (EMBL accession number Z30237) . This encodes a 33.1-kDa protein, SmeR, which has a high degree of homology with NmcR, the LysR regulatory protein of the only other sequenced carbapenem-hydrolyzing class A beta-lactamase, NmcA from Enterobacter cloacae NOR-1 . It is weakly related to AmpR of the chromosomal cephalosporinase regulatory systems described in E . cloacae, Yersinia enterocolitica, Citrobacter freundii, and Pseudomonas aeruginosa and is very weakly related to other LysR-type regulators of class A beta-lactamases . SmeR is a weakly positive regulator for Sme-1 expression in the absence of or in the presence of beta-lactam inducers . The -35 and -10 regions of smeR are in the opposite orientations and are face-to-face relative to the smeA promoter . SmeR acts similarly to NmcR and not as the AmpR regulators described for class C beta-lactamase systems . SmeR is a weak inducer in the absence or presence of beta-lactams . As was found for the AmpC-AmpR and NmcA-NmcR systems, a putative SmeR-binding site was present upstream from the beta-lactamase gene promoter regions . beta-Galactosidase activity from a smeR-lacZ translational fusion was expressed constitutively and decreased in the presence of SmeR from a coresident plasmid, suggesting that SmeR is autogeneously controlled . Finally, beta-lactams did not affect the expression of SmeR, which is the second regulator of a class A carbapenem-hydrolyzing beta-lactamase to be identified. Diagn Microbiol Infect Dis, 1995 Mar, 21(3), 141 - 51 National survey of the in vitro spectrum of piperacillin-tazobactam tested against more than 40,000 aerobic clinical isolates from 236 medical centers; Baron EJ et al.; Hospital microbiology laboratories from 41 states participated in a bacterial antimicrobial susceptibility study comparing in vitro results generated by the standardized disk diffusion method . Over 41,000 freshly isolated aerobic and facultative strains, representing all specimen types (except stools and urines), were tested for their susceptibility to piperacillin-tazobactam and 21 other antimicrobial agents . Enterococcus spp . was the second or third most common isolate from intraabdominal, gynecologic, and cutaneous infections, confirming its growing importance as a nosocomial pathogen . Escherichia coli was the most frequent isolate overall, despite the exclusion of urinary tract specimens from the study . Pseudomonas aeruginosa was the second most prevalent species, ranking first in frequency of recovery from lower-respiratory-tract specimens . Piperacillin-tazobactam was the most active beta-lactamase inhibitor combination tested against Gram-negative bacteria . Its activity against Gram-positive bacteria and Haemophilus influenzae was similar to that of ampicillin-sulbactam (95-97% susceptible) . Imipenem and piperacillin-tazobactam displayed similar spectrums of activity against Gram-positive organisms and Haemophilus influenzae . Against Enterobacteriaceae, piperacillin-tazobactam and ceftazidime exhibited similarly wide spectrums of activity, but with some gaps, particularly among Enterobacter spp . and Citrobacter freundii . In this large-scale in vitro study, piperacillin-tazobactam and imipenem displayed the widest antimicrobial spectrums, inhibiting > 90% of all isolates tested. Eur J Clin Microbiol Infect Dis, 1995 Mar, 14(3), 244 - 52 Multicentre comparative study on the antibacterial activity of FK-037, a new parenteral cephalosporin; Martinez-Beltran J et al.; The in vitro antibacterial activity of FK-037, a new parenteral cephalosporin structurally related to cefpirome and cefepime, was compared with that of cefotaxime, ceftazidime, aztreonam, cefpirome, cefepime, imipenem and meropenem against 1,837 clinical isolates obtained from three Spanish hospitals . FK-037 inhibited 90% of Enterobacteriaceae isolates at < or = 0.25 microgram/ml, with the exception of Enterobacter aerogenes (MIC90 1 microgram/ml), Enterobacter cloacae and Citrobacter freundii (MIC90 8 micrograms/ml) . In cefotaxime- and ceftazidime-resistant Klebsiella pneumoniae strains producing SHV-2 and SHV-6 beta-lactamases, the activity of FK-037, cefpirome and cefepime was similar (MIC range 0.25-32 micrograms/ml) . In Enterobacteriaceae strains hyper-producing chromosomally inducible beta-lactamases, FK-037 (MIC90 range, 0.25-8 micrograms/ml) was 8- to 16-fold more active than cefotaxime and ceftazidime but two- to eightfold less active than cefpirome and cefepime . FK-037 and cefpirome were twofold more active than ceftazidime and cefepime against Pseudomonas aeruginosa isolates, with MIC90 values of 16 micrograms/ml . The activity of FK-037, cefpirome and cefepime was two- to eightfold lower in ceftazidime-resistant derepressed Pseudomonas aeruginosa mutants . FK-037 (MIC range, 0.12-2 micrograms/ml) and the other beta-lactam agents tested were active against methicillin-s