title: Prevalence and characteristics of extended-spectrum β-lactamase and plasmid-mediated fluoroquinolone resistance genes in Escherichia coli isolated from chickens in Anhui province, China.
abstract: The aim of this study was to characterize the prevalence of extended-spectrum β-lactamase (ESBL) genes and plasmid-mediated fluoroquinolone resistance (PMQR) determinants in 202 Escherichia coli isolates from chickens in Anhui Province, China, and to determine whether ESBL and PMQR genes co-localized in the isolates. Antimicrobial susceptibility for 12 antimicrobials was determined by broth microdilution. Polymerase chain reactions (PCRs), DNA sequencing, and pulsed field gel electrophoresis (PFGE) were employed to characterize the molecular basis for β-lactam and fluoroquinolone resistance. High rates of antimicrobial resistance were observed, 147 out of the 202 (72.8%) isolates were resistant to at least 6 antimicrobial agents and 28 (13.9%) of the isolates were resistant to at least 10 antimicrobials. The prevalence of blaCTX-M, blaTEM-1 and blaTEM-206 genes was 19.8%, 24.3% and 11.9%, respectively. Seventy-five out of the 202 (37.1%) isolates possessed a plasmid-mediated quinolone resistance determinant in the form of qnrS (n = 21); this determinant occurred occasionally in combination with aac(6')-1b-cr (n = 65). Coexistence of ESBL and/or PMQR genes was identified in 31 of the isolates. Two E. coli isolates carried blaTEM-1, blaCTX-M and qnrS, while two others carried blaCTX-M, qnrS and aac(6')-1b-cr. In addition, blaTEM-1, qnrS and aac(6')-1b-cr were co-located in two other E. coli isolates. PFGE analysis showed that these isolates were not clonally related and were genetically diverse. To the best of our knowledge, this study is the first to describe detection of TEM-206-producing E. coli in farmed chickens, and the presence of blaTEM-206, qnrS and aac(6')-1b-cr in one of the isolates.
authors.affiliation: Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, P. R. China.
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.affiliation: Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, P. R. China.
authors.forename: Binting
authors.initials: B
authors.lastname: Wang
authors.affiliation: Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, P. R. China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Feng
authors.affiliation: Microbiology and Immunology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, P. R. China.
authors.forename: Jinnian
authors.initials: J
authors.lastname: Li
authors.affiliation: Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, College of Veterinary Medicine, China Agricultural University, Beijing, P. R. China.
authors.forename: Congming
authors.initials: C
authors.lastname: Wu
authors.affiliation: Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, P. R. China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, P. R. China.
authors.forename: Xiangchun
authors.initials: X
authors.lastname: Ruan
authors.affiliation: Pharmacology and Toxicology Laboratory, College of Animal Science and Technology, Anhui Agricultural University, Hefei, P. R. China.
authors.forename: Minghua
authors.initials: M
authors.lastname: Zeng
mesh_terms: D000818:Animals; D002645:Chickens; D002681:China; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D024841:Fluoroquinolones; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D024841:Fluoroquinolones; D001618:beta-Lactamases