title: Role of the outer membrane for quinolone resistance in enterobacteria.
abstract: Quinolone-resistant clones were selected from clinical Escherichia coli, Citrobacter freundii and Serratia marcescens isolates in a frequency ranging from 10(-8) to 10(-6). The outer membrane proteins of quinolone-resistant E. coli clones remained unaltered, as was the case for 10 of 11 C. freundii and 4 of 11 S. marcescens clones ('nal B' type). There was no strong relation between alterations of outer membrane proteins and cross-resistance with chemically unrelated compounds such as tetracycline or chloramphenicol; however, tetracycline resistance was observed in some C. freundii clones with unaltered outer membrane proteins ('mar A'). Most of the quinolone-resistant S. marcescens clones can be considered 'nor B' or 'nor C' mutants due to their cross-resistance with other compounds, their altered outer membrane proteins and changes of lipopolysaccharide. In a few cases, subinhibitory quinolone concentrations caused alterations of outer membrane proteins in S. marcescens during mid log phase without development of resistance.
authors.affiliation: Department of Medical Microbiology and Immunology, Ruhr University, Bochum, FRG.
authors.forename: M
authors.initials: M
authors.lastname: Dechène
authors.forename: H
authors.initials: H
authors.lastname: Leying
authors.forename: W
authors.initials: W
authors.lastname: Cullmann
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis*; D002939:Ciprofloxacin / Q000031:analogs & derivatives / Q000494:pharmacology; D002954:Citrobacter / Q000187:drug effects* / Q000254:growth & development; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D016576:Fleroxacin; D008070:Lipopolysaccharides / Q000032:analysis*; D009268:Nalidixic Acid / Q000494:pharmacology; D015242:Ofloxacin / Q000494:pharmacology; D012706:Serratia marcescens / Q000187:drug effects* / Q000254:growth & development; D013045:Species Specificity
chemical_list: D000890:Anti-Infective Agents; D001425:Bacterial Outer Membrane Proteins; D008070:Lipopolysaccharides; D009268:Nalidixic Acid; D002939:Ciprofloxacin; D015242:Ofloxacin; D016576:Fleroxacin