title: Escherichia coli isolates from sick chickens in China: changes in antimicrobial resistance between 1993 and 2013.
abstract: The use of antimicrobials for the control of infectious disease has increased in recent decades. Understanding trends in antimicrobial resistance provides clues about the relationship between antimicrobial use and the emergence of resistance. We examined the resistance of 540 Escherichia coli isolates to 19 antimicrobials that represent 11 classes of antimicrobial agents. The isolates were collected from chickens between 1993 and 2013 in China. Overall, >96.7% of the isolates were resistant to at least one of the tested compounds, and 87.2% of them displayed multidrug resistance (MDR) representing five to six antimicrobial classes. A high proportion of E. coli isolates were resistant to tetracycline (90.6%), nalidixic acid (80.6%), ampicillin (77.2%), trimethoprim-sulfamethoxazole (76.9%), and streptomycin (72.8%). Only 3.0% of the isolates were resistant to nitrofurantoin, and none was resistant to meropenem. Resistance to amikacin, ampicillin, aztreonam, ceftazidime, cefotaxime, cephalothin, chloramphenicol, ciprofloxacin, fosfomycin, levofloxacin, norfloxacin, nalidixic acid, piperacillin, and trimethoprim-sulfamethoxazole significantly increased from 1993 to 2013 (P <0.01). There was an increasing trend in MDR over the 20 year period.
authors.affiliation: Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Centre for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Chen
authors.affiliation: Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Centre for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
authors.forename: Weiqiu
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Centre for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
authors.forename: Jiajun
authors.initials: J
authors.lastname: Yin
authors.affiliation: Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Centre for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Centre for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
authors.forename: Shizhong
authors.initials: S
authors.lastname: Geng
authors.affiliation: Department of Pathobiology and Veterinary Sciences, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Centre for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Centre for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
authors.forename: Song
authors.initials: S
authors.lastname: Gao
authors.affiliation: Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Centre for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China. Electronic address: jiaoxa@yzu.edu.cn.
authors.forename: Xinan
authors.initials: X
authors.lastname: Jiao
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002645:Chickens; D002681:China / Q000453:epidemiology; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects*; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D011201:Poultry Diseases / Q000453:epidemiology / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antimicrobial resistance; Chicken; Escherichia coli; Multidrug resistance