title: Presence of qnr, aac(6')-Ib, qepA, oqxAB, and mutations in gyrase and topoisomerase in nalidixic acid-resistant Salmonella isolates recovered from retail chicken carcasses.
abstract: Four hundred sixty-two nalidixic acid- and/or ciprofloxacin-resistant Salmonella isolates were examined for presence of quinolone-resistance mechanisms. A total of 339 amino acid substitutions were identified in GyrA (204) and ParC (135). Ser83Phe/Asp87Gly (29.4%) were most commonly detected in GyrA in 136 isolates, and to a lesser extent of Asp87Asn (22.8%), Asp87Gly (19.1%), Ser83Phe/Asp87Asn (19.1%), and Ser83Tyr (5.1%). Ser80Arg (97.0%) was detected in ParC in 132 isolates. Simultaneous mutations in GyrA and ParC (n=109) were commonly detected to be Ser83Phe/Asp87Gly(GyrA)-Ser80Arg(ParC) (35.8%), Asp87Asn(GyrA)-Ser80Arg(ParC) (22.9%), and Ser83Phe/Asp87Asn(GyrA)-Ser80Arg(ParC) (21.1%). qnrA, qnrB, qnrS, aac(6')-Ib, qepA, and oqxAB were detected in 52 (11.3%), 64 (13.9%), 11(2.4%), 107 (23.2%), 6 (1.3%), and 194 (42.0%) of 462 isolates, respectively. Isolates carried more qnr, aac(6')-Ib, qepA, and oqxAB genes, and amino acid substitution in GyrA and ParC was more resistant to nalidixic acid and fluoroquinolones.
authors.affiliation: 1 College of Food Science and Engineering, Northwest A&F University , Yangling, China .
authors.forename: Zengfeng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Meng
authors.forename: Yin
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xia
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Meili
authors.initials: M
authors.lastname: Xi
authors.forename: Jianghong
authors.initials: J
authors.lastname: Meng
authors.forename: Xianming
authors.initials: X
authors.lastname: Shi
authors.forename: Dapeng
authors.initials: D
authors.lastname: Wang
authors.forename: Baowei
authors.initials: B
authors.lastname: Yang
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D002645:Chickens / Q000382:microbiology; D027081:DNA Gyrase / Q000235:genetics; D026942:DNA Topoisomerases / Q000235:genetics; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D024841:Fluoroquinolones / Q000494:pharmacology; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009268:Nalidixic Acid / Q000494:pharmacology; D011200:Poultry / Q000382:microbiology*; D015363:Quinolones / Q000494:pharmacology; D012475:Salmonella / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D012478:Salmonella Food Poisoning / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D024841:Fluoroquinolones; D015363:Quinolones; D009268:Nalidixic Acid; D026942:DNA Topoisomerases; D027081:DNA Gyrase