title: Ability of newer beta-lactam antibiotics to induce beta-lactamase production in Enterobacter cloacae.
abstract: The beta-lactamase inducing properties of various new beta-lactam antibiotics in two isogenic strains of Enterobacter cloacae were investigated. Beta-lactamase activity was measured two hours after addition of inducer to cells in the late logarithmic growth-phase. Beta-lactamase expression was highly dependent on the growth medium used, highest levels being obtained after induction with cefoxitin in Tryptic Soy broth, Mueller-Hinton broth and Nutrient broth. Upon induction the mutant 908 Ssi produced tenfold higher beta-lactamase levels than its parent wild type 908 Swi. Among the new antibiotics investigated, sulfoxides of several oxyimino-cephalosporins, HR 810, cefetamet, cefteram, carumonam and BRL 36650 were moderate or poor inducers. The penem FCE 22101 resembled imipenem in its strong inducing properties.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003470:Culture Media; D004754:Enterobacter / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D004755:Enterobacteriaceae / Q000201:enzymology*; D004790:Enzyme Induction / Q000187:drug effects; D009154:Mutation; D001618:beta-Lactamases / Q000096:biosynthesis*; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D047090:beta-Lactams; D001618:beta-Lactamases