title: Molecular epidemiological survey on quinolone resistance genotype and phenotype of Escherichia coli in septicemic broilers in Hebei, China.
abstract: In this study, the quinolone-resistant determining region (QRDR) of gyrA of Escherichia coli and plasmid-mediated quinolone resistance (PMQR) genes, qnr(qnrA, qnrB, and qnrS), and aac(6 ')-Ib-cr were detected, sequenced, and analyzed. In addition, antimicrobial susceptibility tests (using the Kirby-Bauer disc diffusion method) were performed for all 111 E. coli isolates from septicemic broilers in Hebei, China. The results show that the resistance rates were as follows: ofloxacin 99.10%, ciprofloxacin 93.69%, levofloxacin 91.89%, norfloxacin 90.09%, and gatifloxacin 76.58%. Of the PMQR genes examined, aac(6 ')-Ib-cr (36.04%) was the most frequently identified gene in all isolates, followed by qnrS (8.11%), qnrB (0.90%), and qnrA (0%). Of the QRDR examined in the 40 phenotypic quinolone-resistant isolates, compared with the gyrA(+) gene of E. coli K-12, 4 amino acid exchanges were found, namely Ser-83→Asp, Asp-87→Asn, Asp-87→Tyr, and Asp-87→Ala, and all 40 isolates had 1 or 2 exchanges in QRDR. It was concluded that quinolone-resistance in E. coli remains a serious problem in Hebei, China. Therefore, there is considerable local surveillance of quinolone resistance. Plasmid-mediated quinolone resistance of the qnr type remains rare in Hebei, China, and mutation in QRDR may be the main problem.
authors.affiliation: College of Veterinary Medicine, Hebei Agricultural University; North China Research Center of Animal Epidemic Pathogen Biology, China Agriculture Ministry, Baoding, 071001, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Xie
authors.forename: Shuying
authors.initials: S
authors.lastname: Huo
authors.forename: Yurong
authors.initials: Y
authors.lastname: Li
authors.forename: Ligong
authors.initials: L
authors.lastname: Chen
authors.forename: Feiyan
authors.initials: F
authors.lastname: Zhang
authors.forename: Xianjun
authors.initials: X
authors.lastname: Wu
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002645:Chickens; D002681:China / Q000453:epidemiology; D027081:DNA Gyrase / Q000235:genetics* / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011201:Poultry Diseases / Q000453:epidemiology / Q000382:microbiology; D015995:Prevalence; D015363:Quinolones / Q000494:pharmacology*; D017422:Sequence Analysis, DNA / Q000662:veterinary
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D015363:Quinolones; D027081:DNA Gyrase
keywords: Escherichia coli; PCR; broiler; quinolone resistance; resistance gene