Open AccessPoint mutation in the pribnow box, the molecular basis of beta-lactamase overproduction in Klebsiella oxytoca
Author(s) -
Bénédicte Fournier,
Changyuan Lu,
Philippe Lagrange,
R. Krishnamoorthy,
A. Philippon
Publication year - 1995
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.39.6.1365
Subject(s) - klebsiella oxytoca , transversion , mutant , point mutation , biology , gene , microbiology and biotechnology , genetics , klebsiella , aztreonam , mutation , enterobacteriaceae , antibiotics , antibiotic resistance , escherichia coli , imipenem
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.