title: Examination of methicillin-resistant and methicillin-susceptible Staphylococcus aureus mutants with low-level fluoroquinolone resistance.
abstract: For Staphylococcus aureus, stepwise mutations result in high-level quinolone resistance. Methicillin-resistant and -susceptible quinolone-resistant, first-step mutants generated in vitro were obtained and found to be no different than those recovered from murine abscesses. Approximately 10% of all first-step mutants were resistant to ethidium bromide, and selected strains had mutations that mapped to flqB. NorA-mediated resistance among first-step mutants may be more prevalent than previously reported.
authors.affiliation: Department of Medicine, Division of Infectious Diseases, University of Michigan Medical School, and Department of Veterans Affairs Medical Center, Ann Arbor, Michigan, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Sulavik
authors.forename: N L
authors.initials: NL
authors.lastname: Barg
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002874:Chromosome Mapping; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004352:Drug Resistance, Microbial; D024841:Fluoroquinolones; D008040:Genetic Linkage; D008712:Methicillin / Q000494:pharmacology*; D016106:Methicillin Resistance; D051379:Mice; D008826:Microbial Sensitivity Tests; D009154:Mutation; D010406:Penicillins / Q000494:pharmacology*; D010641:Phenotype; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000890:Anti-Infective Agents; D004269:DNA, Bacterial; D024841:Fluoroquinolones; D010406:Penicillins; D008712:Methicillin