title: Expression of beta-lactamases in Yersinia enterocolitica strains of biovars 2, 4 and 5.
abstract: Characteristic patterns of susceptibility to beta-lactam antibiotics are associated with different biovars of Yersinia enterocolitica. To elucidate the basis for these differences, the beta-lactamases of strains of Y. enterocolitica biovars 4 (n = 63), 2 (n = 12) and 5 (n = 10) were characterised. PCR fragments were generated from the beta-lactamase A (blaA) and B (blaB) genes; in addition, beta-lactamase induction tests were performed with imipenem as the inducer and beta-lactamase inhibition assays were undertaken with aztreonam and clavulanic acid. All the strains yielded PCR amplification fragments with primers to blaA and blaB. Biovar 4 strains had uniform patterns of beta-lactamase induction and inhibition: uninduced biovar 4 strains predominantly expressed BlaA, but low-level expression of BlaB was also detected; after induction, biovar 4 strains predominantly produced BlaB. Beta-lactamase expression varied between and within biovars 2 and 5: uninduced strains predominantly expressed either BlaA or BlaB, or exclusively BlaB; after induction BlaB was predominantly or exclusively expressed. Both the basal and induced levels of beta-lactamase varied within biovars 2 and 5. Some biovar 5 strains were not inducible; these predominantly produced BlaA. The results of this study show that biovar 2, 4 and 5 strains contain both blaA and blaB, but that the expression of the enzymes is regulated differently between the biovars, and varies within biovars 2 and 5. There was some correlation between antibiogram and the clusters defined from the beta-lactamase induction and inhibition tests, but it was not possible to predict beta-lactamase expression profiles from MIC data.
authors.forename: Ingo
authors.initials: I
authors.lastname: Stock
authors.forename: Peter
authors.initials: P
authors.lastname: Heisig
authors.forename: Bernd
authors.initials: B
authors.lastname: Wiedemann
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005858:Germany; D006801:Humans; D007793:Lagomorpha; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D013552:Swine; D014871:Water Microbiology; D015008:Yersinia enterocolitica / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D001618:beta-Lactamases