title: Low-level resistance to the cephalosporin 3'-quinolone ester Ro 23-9424 in Escherichia coli.
abstract: Four spontaneous, single-step mutants of Escherichia coli K-12 resistant to low levels of the cephalosporin 3'-quinolone ester Ro 23-9424 were isolated at a frequency of 10(-10) to 10(-11) mutants per CFU plated. The mutants were cross-resistant to both cephalosporin (cefotaxime) and quinolone (fleroxacin) components. Accordingly, they had altered porins and replicative DNA biosynthesis resistant to fleroxacin. There was no increase in beta-lactamase activity when tested with nitrocephin, and the penicillin-binding protein profiles were normal.
authors.affiliation: Roche Research Center, Nutley, New Jersey 07110, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Chapman
authors.forename: A
authors.initials: A
authors.lastname: Bertasso
authors.forename: L M
authors.initials: LM
authors.lastname: Cummings
authors.forename: N H
authors.initials: NH
authors.lastname: Georgopapadakou
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D002439:Cefotaxime / Q000031:analogs & derivatives* / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects*; D016576:Fleroxacin / Q000031:analogs & derivatives* / Q000494:pharmacology; D024841:Fluoroquinolones; D008826:Microbial Sensitivity Tests
chemical_list: D000890:Anti-Infective Agents; D024841:Fluoroquinolones; C060441:Ro-23-9424; D002439:Cefotaxime; D016576:Fleroxacin