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PubMed1966

Episome-mediated Transfer of Drug Resistance in Enterobacteriaceae X. Restriction and Modification of Phages by fi R Factors.

Watanabe, Tsutomu (Keio University, Tokyo, Japan), Toshiya Takano, Toshihiko Arai, Hiroshi Nishida, and Sachiko Sato. Episome-mediated transfer of drug resistance in Enterobacteriaceae. X. Restriction and modification of phages by fi(-) R factors. J. Bacteriol. 92:477-486. 1966.-An fi(-) R factor, which restricts phages lambda, T1, and T7 without modifying them, was found to restrict and not to modify an F(-)-specific phage, W-31, in Escherichia coli K-12, but not to restrict phage P-22 in Salmonella typhimurium LT-2, whereas other fi(-) R factors restricted and modified P-22 but not W-31; fi(+) R factors did not restrict these phages. Transduction and lysogenization with phages lambda and P-22 were reduced by these fi(-) R factors in K-12 and LT-2, respectively, and the transducing phages lambda and P-22 were modified by these fi(-) R factors. Spontaneous as well as ultraviolet-induced production of phage P-22 and zygotic induction of phage lambda were not significantly affected by any R factor. Injection of the nucleic acids of phages T1 and lambda was not affected by R factors, but the injected phage nucleic acids were rapidly broken down in the bacteria carrying fi(-) R factors. The nucleic acids of the modified phages were not broken down in these bacteria. It was assumed from these results that the mechanism of restriction of phages by fi(-) R factors is due to the breakdown of the injected phage nucleic acids by a deoxyribonuclease(s), presumably located near the cell surface in the cells carrying fi(-) R factors. The deoxyribonuclease(s), formed in the cells carrying the nonmodifying fi(-) R factor, is considered to be different from that synthesized in the cells carrying the modifying fi(-) R factors. It was further shown that the average burst sizes of the unmodified as well as modified phages are slightly reduced by the presence of the fi(-) R factors.

Journal Article↗
PubMed1969

Immunochemical and enzymatic comparisons of the tryptophan synthase alpha subunits from five species of Enterobacteriaceae.

The reactive surface structures of alpha subunits of tryptophan synthase from Escherichia coli, Shigella dysenteriae, Salmonella typhimurium, Aerobacter aerogenes, and Serratia marcescens were compared by measuring (i) their reactivities in micro-complement-fixation assays with antibodies directed specifically to E. coli wild-type alpha subunit, (ii) their reactivities in enzyme neutralization assays with the same antibodies, and (iii) their binding affinities for tryptophan synthase beta(2) subunits. The enzymes from the four heterologous species cross-reacted in the microcomplement-fixation assays with the anti-E. coli alpha subunit antibodies, each to a different degree. However, neutralization titers of the antibodies reacting with the various alpha subunits were comparatively similar, and the beta(2) subunit-binding and -stimulating abilities of the alpha subunits were even more closely alike. The results suggested that the tertiary structure of the beta(2) subunit-binding site of the alpha subunit has been conserved, relative to the rest of the molecule, during the evolutionary divergence of the species of Enterobacteriaceae.

Antigen-Antibody Reactions↗
PubMed1963

The differentiation of Enterobacteriaceae infecting the urinary tract: A study in male paraplegics.

Methods adopted in a routine bacteriology laboratory for the rapid identification of Enterobacteriaceae isolated from urine are described. The incidence of various bacteria causing infection in paraplegics after catheterization of the bladder is recorded, Klebsiella accounting for the majority of infections caused by lactose fermenters and Providence for the majority of ;paracolon' infections. The importance of these bacteria in cross-infection is discussed.

Journal Article↗
PubMed1977

Lipids of antibiotic-resistant and -susceptible members of the Enterobacteriaceae.

Lipids of antibiotic-resistant and related -susceptible strains of the Enterobacteriaceae were extracted with chloroform-methanol and characterized by thin-layer chromatography, densitometry, and fatty acid analysis using gas chromatography. Quantitative differences which correlated with antibiotic resistance existed among the phospholipids and fatty acids. A relatively higher concentration of a ninhydrin-positive phospholipid concentration with a lower amount of phosphatidylethanolamine was observed in antibiotic-resistant strains of serratia marcescens. Bacterial strains which harbored R-factor 222 had a higher ratio of phosphatidylglycerol to diphosphatidylglycerol than their respective parent strains while those strains which were resistant to the polymyxins had a lower ratio of these phospholipids. Differences in the relative amounts of certain unsaturated and cyclopropane fatty acids were observed between susceptible and resistant strains. Such differences, however, were dependent upon a particular genus and species.

Anti-Bacterial Agents↗
PubMed1986

Comparative antibacterial effects of amoxycillin, amoxycillin/clavulanic acid and cefotaxime against Enterobacteriaceae as determined by turbidimetry, morphology and viable count.

Cefotaxime has extremely low MIC values in comparison with amoxycillin against Enterobacteriaceae, but studies of antibacterial activity using turbidimetric and viable count methods show no advantage for cefotaxime. Superior rates of killing have been demonstrated for amoxycillin and amoxycillin/clavulanic acid using both constant antibiotic concentrations and changing concentrations to simulate conditions in vivo. Slow bactericidal activity was seen with cefotaxime even at levels greatly in excess of the MIC and could be correlated with filament formation by this compound over a wide range of concentrations.

Amoxicillin↗
PubMed1996

Occurrence of a novel L-2,4-diaminobutyrate decarboxylase activity in some species of Enterobacteriaceae, and purification and characterization of the enzymes of Enterobacter aerogenes and Serratia marcescens.

L-2,4-Diaminobutyrate decarboxylase (DABA DC) is a novel enzyme yielding 1,3-diaminopropane (DAP) from DABA, which has previously been purified from strains of the genera Vibrio and Acinetobacter. In this study, we also detected DABA DC activity in the species of Enterobacteriaceae: E. aerogenes, E. cloacae, E. agglomerans, Serratia marcescens, S. liquefaciens, Klebsiella pneumoniace, K. oxytoca and Citrobacter freundii, all of which produced DAP in sufficient amounts. Subsequently, the DABA DCs of E. aerogenes and S. marcescens were purified to homogeneity and characterized. Two separate enzymes had similar properties with respect to chromatographic behaviors, and were a dimer with subunits of identical molecular mass of about 51 kDa. The maximal activity of each enzyme was obtained at pH 8.0-8.25. Both enzymes required pyridoxal 5'-phosphate and Mg2+ for full activity, and were highly specific for L-DABA. There was immunological similarity, but not identity between these proteins, as determined by Ouchterlony double diffusion analysis with antiserum against the E. aerogenes DABA DC. They showed the same N-terminal amino acid sequence up to the 8th residue (S-K-L-N-P-I-L-A-). These enzymes were different in molecular mass, N-terminal amino acid sequence and antigenicity from DABA DCs of Acientobacter and Vibrio species.

Carboxy-Lyases↗
PubMed1998

Generation and properties of a luminescent insect pathogen Xenorhabdus nematophilus (Enterobacteriaceae).

Studies on the interaction of the insect pathogenic bacterium, Xenorhabdus nematophilus (Enterobacteriaceae), with its nematode and insect hosts would be greatly assisted if a luminescent phenotype were generated that would allow the detection of viable bacteria in vivo without the necessity for disruption of the cellular interactions. The plasmid, pMGM221, containing the luminescence gene (luxCDABE) of Vibrio harveyi was introduced into different strains (DD136 and 19061) and phases (one and two) of X. nematophilus by triparental mating. For reproducible and efficient conjugation, it was necessary to use older cultures (96-160 h) in the stationary phase of X. nematophilus for mating with relatively small differences (<2-fold) in transconjugant yield for the different strains and phases of X. nematophilus. All transconjugants emitted high levels of light with optimum bioluminescence at 27 degrees C in Luria broth at pH 8.0 containing 20 g/L NaCl; pH, osmolarity, and temperature conditions were similar to those encountered by the bacteria in the hemolymph of the larvae of Galleria mellonella. Plasmids were detected in the transconjugants after 6 months of subculturing the bacteria without antibiotic selection. Aside from light emission, luminescent transconjugants had the same physiological properties as the nonluminescent parental strains, including identical rates of growth, production of exoenzymes, removal from and subsequent emergence into the insect's hemolymph, bacterial-induced hemocyte damage, suppression of prophenoloxidase activation, and the ability to kill G. mellonella larvae. Light-emitting larvae could readily be detected by eye in a dark room, and all bacteria reisolated from dead larvae were luminescent. These properties validate the use of luminescent X. nematophilus not only as a means of following bacterial host interactions, but also as a potential agent to follow the infection and death of the insect population.

Journal Article↗
PubMed1993

Characterization of an SHV-5 related extended broad-spectrum beta-lactamase in Enterobacteriaceae from Western Australia.

Among 209 isolates of aminoglycoside resistant Enterobacteriaceae isolated from patients attending the Sir Charles Gairdner Hospital in Perth, Western Australia between January 1985 and June 1991, 41 strains demonstrated additional resistance to cefotaxime, ceftriaxone, ceftazidime and aztreonam. Significant synergy was demonstrable between these beta-lactams and clavulanic acid against resistant strains. The beta-lactamase was mediated by a 170 Kb self-transferring plasmid and identified as the SHV-5 type in isoelectric focusing (pl 8.2) and substrate hydrolysis kinetic studies. The findings record the introduction of extended broad-spectrum beta-lactamases to Australia.

Anti-Bacterial Agents↗
PubMed2006

[Transference of extended-spectrum beta-lactamases from nosocomial strains of Klebsiella pneumoniae to other species of Enterobacteriaceae].

BACKGROUND: Klebsiella pneumoniae is an important pathogenic bacterium, frequently isolated from nosocomial samples, that exhibits wide antimicrobial resistance profiles, including third generation cephalosporins (3GC), aminoglycosides and quinolones. The resistance to 3GC is mainly due to the synthesis of extended spectrum beta lactamases (ESBL), encoded by conjugative plasmids. AIM: To investigate the potential transference of resistance to 3GC from nosocomial strains of K. pneumoniae to other clinical strains of various species of Enterobacteriaceae. MATERIAL AND METHODS: The mating experiments were carried out in liquid media and three nosocomial strains of K. pneumoniae were used as donors. These strains were ESBL-producers and resistant to, at least, one of the 3GC assayed. One strain of Citrobacter freundii, Salmonella typhimurium, Serratia marcescens and Escherichia coli, isolated from clinical specimens, were used as recipients. The presence of bla genes was investigated by PCR. RESULTS: The three nosocomial strains of K. pneumoniae were able to transfer the resistance to 3GC and the genes encoding the ESBL to the susceptible recipient strains of enterobacteria. The frequency of transference was as high as 3.2 x 10-2 transconjugants/recipient cell when the strain of Citrobacter freundii was used as recipient. All transconjugants exhibited high level of resistance to the 3GC assayed. CONCLUSIONS: Strains of K. pneumoniae isolated from Chilean hospitals are able to disseminate the ESBL genes to clinical strains of others species of Enterobacteriaaceae.

Anti-Bacterial Agents↗
PubMed2001

[Ability of acceptance for bacteriophages during verotoxin production by bacilli of the Enterobacteriaceae family].

Lysogenised verotoxigenic strains are the source of structural genes of verocytotoxins (stx-1 and stx-2) for the others intestinal bacili. The aim of the study was to estimate the ability of transfer of bacteriophages induced with UV irradiation from reference verotoxigenic strains of E. coli O157:H7 (CB571 and EDL933) into 125 wild-strains of bacili of Enterobacteriaceae family. None of tested recipient strains showed the production of cytotoxin on Vero and HeLa cell lines, what was acknowledged as the lack of six genes. Contrary to the laboratory strain of E. coli C600 none of 125 tested recipient strains accepted the phages. Obtained lysogenised laboratory strains of E. coli C600/CB571 and E. coli C600/EDL933, besides of the ability to produce verotoxins (with the presence of stx-1 and stx-2 genes), did not differ phenotypically and genotypically from parent strain of E. coli C600. The estimation of the ability to transfer of phages carried stx-1 and/or stx-2 genes was impossible because of too small number of tested wild strain of bacili or because of really low frequency of acceptation of phages by wild strains of intestinal bacili.

Animals↗
PubMed1978

Purification and properties of a third form of anthranilate-5-phosphoribosylpyrophosphate phosphoribosyltransferase from the Enterobacteriaceae.

Anthranilate-5-phosphoribosylpyrophosphate phosphoribosyltransferase was purified from the bacterium Erwinia carotovora, a member of the Enterobacteriaceae. The enzyme was homogeneous according to the criteria of gel electrophoresis and NH2-terminal amino acid sequence analysis. The molecular weight of the enzyme as determined on a calibrated Sephadex G-200 column was 67,000 +/- 2,000. Sodium dodecyl sulfate-polyacrylamide gels gave a subunit molecular weight of 40,000 +/- 1,000, suggesting that the enzyme was a dimer. A comparison of the NH2-terminal sequence of the enzyme with the (previously determined) homologue from Serratia marcescens, a monomer with a molecular weight of 45,000, showed that the larger Serratia subunit came into register with amino acid 14 of the Erwinia subunit. The register for the length of the known overlap, 26 amino acids, was highly conserved.

Amino Acid Sequence↗
PubMed1979

[Purification and physico-chemical analysis of the fimbrial antigen in two different genera of Enterobacteriacea: Salmonella enteritidis and Yersinia enterocolitica (author's transl)].

Chemical, physical and immunological properties of the fimbrial antigen of two different genera of Enterobacteriaceae, namely Salmonella (S. enteritidis) and Yersinia (Y. enterocolitica) were analysed. Only a few strains of these two bacterial genera possess a fimbrial antigen which proved to be identical in all tests. Purified fimbriae are unstable in buffer solutions. They tend to form aggregates, patterns of which are between 240000 and 270000. Submitted to solubility testing by various methods these aggregates easily dissociate into particles of different molecular size. Treatment with 1% sodium dodecyl sulphate (SDS) in 1% mercaptoaethanol at 37 degrees C for 60 minutes gave constant reproducible results. The fimbrial protein prepared by this method proved to be an antigenically active unit with a molecular weight of 23450 for S. enteritidis and 23350 for Y. enterocolitica. The electron microscope revealed that purified fimbriae of these two genera consist of extremely thin filaments (1.5 to 2.7 nm), covering the bacterial cell as an envelope. They are supposed to be composed of no more than 2 to 3 peptid chains. The presence of the amino acids tyrosine, phenylalanine and tryptophane may be responsible of the particular behaviour of the fimbriae which according to different external conditions react with different states of dissociation. Probably the filaments are not stable in a solution as single filaments but tend to form oligomer, secondary and tertiary structures. Experiments of isoelectric focusing revealed that both antigens consist of a pure protein component (composed of 17 amino acids) which appears at pH 3.9.

Antigens, Bacterial↗
PubMed1982

Bacterial adhesiveness and invasiveness in cell culture monolayer. 2. In vitro invasiveness of 45 strains belonging to the family Enterobacteriaceae.

The invasive potential of 45 presumptive enteropathogenic and non-enteropathogenic bacterial strains belonging to the family Enterobacteriaceae have been tested using the Serény test and HEp-2 cell monolayers examined by a combined light optical method. All the presumptive enteropathogenic strains of Shigella dysenteriae, S. boydii, S. flexneri, S. sonnei and Salmonella typhimurium showed in vitro invasiveness in the HEp-2 cell culture test. Fourteen presumptive non-enteropathogenic strains of Escherichia coli showed no invasiveness in either of the two test systems. Two strains of S. flexneri and all the 6 strains of S. typhimurium gave a negative result in the Serény test although they were invasive in HEp-2 cell cultures. Otherwise there were correlative results between the cell monolayer test and the Serény test. In the cell monolayer test the different species of enteropathogenic bacteria showed considerable variation in invasive potential.

Adhesiveness↗
PubMed1981

[Distribution of transferable trimethoprim and gentamicin resistance plasmids in Enterobacteriaceae].

Following the employment of trimethoprim/sulfonamid and gentamicin in the general clinical praxis transferable plasmids with respective resistance function were identified at first in enteric bacteria from sewage before they could be detected in patient strains. Whereas the trimethoprim resistance plasmids represent different incompatibility groups (C, FII, I5, K, M, N, S, U) the gentamicin resistance plasmids are very similar IncM members of 62 MD in size. Therefore a clonal distribution of a particular gentamicin resistance plasmid has to be taken into consideration.

DNA Transposable Elements↗
PubMed1993

A survey of clinical isolates of Enterobacteriaceae using a series of DNA probes for aminoglycoside resistance genes.

DNA probes specific for the aminoglycoside adenylyltransferase ANT(2"), the aminoglycoside phosphotransferases APH(3')-I and APH(3')-II, and the aminoglycoside acetyltransferases AAC(3)-I, AAC(3)-V and AAC(6')-I were used to screen 151 clinical isolates for the presence of these resistance determinants. The two most common resistance genes in the study isolates were those encoding ANT(2") and APH(3')-I. The phenotypic pattern of aminoglycoside resistance, as determined by a modified disk diffusion test correlated well with the genotypes of the organisms as established using DNA probes, although strains carrying the ANT(2") gene could express one of several phenotypes.

Acetyltransferases↗