title: Point mutation in the pribnow box, the molecular basis of beta-lactamase overproduction in Klebsiella oxytoca.
abstract: Klebsiella oxytoca mutants resistant to a variety of beta-lactams were obtained in vitro on aztreonam. Constitutive beta-lactamase production was much higher in the mutants than in the susceptible strains (75-fold). The only difference observed in these mutants compared with the susceptible strains were point mutations in the Pribnow box: a transversion (G-->T) in the first base for one mutant or a transition (G-->A) in the fifth base of the -10 consensus sequence for the other three mutants. The transcriptional output of the beta-lactamase gene (blaOXY) from the mutants was significantly higher than that of the blaOXY gene from the susceptible strains.
authors.affiliation: Laboratoire de Microbiologie, Hôpital Saint-Louis, Université Paris VII, France.
authors.forename: B
authors.initials: B
authors.lastname: Fournier
authors.forename: C Y
authors.initials: CY
authors.lastname: Lu
authors.forename: P H
authors.initials: PH
authors.lastname: Lagrange
authors.forename: R
authors.initials: R
authors.lastname: Krishnamoorthy
authors.forename: A
authors.initials: A
authors.lastname: Philippon
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001483:Base Sequence; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000032:analysis; D015964:Gene Expression Regulation, Bacterial; D007709:Klebsiella / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D015533:Transcriptional Activation; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics*; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D047090:beta-Lactams; D001618:beta-Lactamases