title: In vitro fluoroquinolone-resistant mutants of Salmonella enterica serotype Enteritidis: analysis of mechanisms involved in resistance.
abstract: This study analysed the mechanisms involved in the acquisition of resistance to quinolones in mutants obtained in vitro of Salmonella enterica serotype Enteritidis. Two nalidixic acid-resistant (minimal inhibitory concentrations, MIC>256 mg/l), ciprofloxacin-susceptible (MIC 0.5 mg/l) clinical isolates of Salmonella Enteritidis with a mutation at amino acid codon Ser-83 of the gyrA gene were grown on plates containing increasing concentrations of ciprofloxacin. The increase in MIC to ciprofloxacin, sparfloxacin and trovafloxacin was totally or partially associated with over-expression of an AcrAB-like efflux pump. In addition, unidentified mechanism(s) may have been involved in the increased MIC to these antimicrobials. This study demonstrated that AcrAB-like efflux pumps appear to play a relevant role in the increase in MIC to some quinolones although, other, as yet undefined, mechanisms may be involved.
authors: Department of Functional Biology, University of Oviedo, Julián Clavería s/n, 33006, Oviedo, Spain.
authors: Sara M
authors: SM
authors: Soto
authors: Joaquim
authors: J
authors: Ruíz
authors: M Carmen
authors: MC
authors: Mendoza
authors: Jordi
authors: J
authors: Vila
mesh_terms: D002939:Ciprofloxacin / Q000494:pharmacology; D027081:DNA Gyrase / Q000235:genetics* / Q000502:physiology; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D008826:Microbial Sensitivity Tests; D009268:Nalidixic Acid / Q000494:pharmacology; D019779:Salmonella enterica / Q000187:drug effects* / Q000235:genetics
chemical_list: D024841:Fluoroquinolones; D009268:Nalidixic Acid; D002939:Ciprofloxacin; D027081:DNA Gyrase