title: Relative contribution of target gene mutation and efflux to varying quinolone resistance in Irish Campylobacter isolates.
abstract: The contribution of target gene mutations and active efflux to varying levels of quinolone resistance in Irish Campylobacter isolates was studied. The Thr-86-Ile modification of GyrA did not correlate with the level of quinolone resistance. The efflux pump inhibitor Phe-Arg-beta-Naphthylamide (PAbetaN) had no effect on the MICs to ciprofloxacin. In contrast, a PAbetaN sensitive efflux system contributed to the low-level nalixidic acid resistance phenotype. The lack of effect of PAbetaN in high-level resistant nalidixic isolates may be attributable to mutations identified in the CmeB efflux pump of these isolates. PAbetaN may have limited diagnostic value in the assessment of the contribution of efflux pump activity to ciprofloxacin resistance in Campylobacter.
authors.affiliation: Centre for Food Safety, School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Deborah
authors.initials: D
authors.lastname: Corcoran
authors.forename: Teresa
authors.initials: T
authors.lastname: Quinn
authors.forename: Leslie
authors.initials: L
authors.lastname: Cotter
authors.forename: Séamus
authors.initials: S
authors.lastname: Fanning
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D001693:Biological Transport, Active / Q000187:drug effects / Q000235:genetics; D002167:Campylobacter / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D002169:Campylobacter Infections / Q000188:drug therapy / Q000382:microbiology; D017000:Campylobacter coli / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D016123:Campylobacter jejuni / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D002939:Ciprofloxacin / Q000494:pharmacology; D004269:DNA, Bacterial / Q000235:genetics; D004151:Dipeptides / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000235:genetics; D024841:Fluoroquinolones / Q000494:pharmacology; D005798:Genes, Bacterial; D006801:Humans; D007494:Ireland; D008969:Molecular Sequence Data; D009154:Mutation; D017386:Sequence Homology, Amino Acid
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004151:Dipeptides; D024841:Fluoroquinolones; C474925:phenylalanylarginine-naphthylamide; D002939:Ciprofloxacin