China Animal Husbandry and Veterinary Medicine ›› 2023, Vol. 50 ›› Issue (12): 5148-5159.doi: 10.16431/j.cnki.1671-7236.2023.12.036

• Basic Veterinary Medicine • Previous Articles     Next Articles

Prevalence and Drug Resistance Analysis of Escherichia coli with Colistin Resistance Gene mcr-1 from Chickens

GAO Xiao, XU Yakun, DING Pengyun, MA Shengnan, PAN Yushan, YUAN Li, HU Gongzheng, HE Dandan   

  1. College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
  • Received:2023-05-22 Online:2023-12-05 Published:2023-11-28
  • Contact: 国家自然科学基金项目(32072923);河南省高校科技创新人才支持计划(23HASTIT039) E-mail:hedandan_68@126.com

Abstract: 【Objective】 The aim of this experiment was to investigate the prevalence of Escherichia coli with plasmid-mediated colistin resistance gene mcr-1 in different regions and years,and to analyze its drug resistance.【Method】 In 2017,2018,2019 and 2021,anal swabs and fecal samples of chicken were randomly collected from Kaifeng and Nanyang in Henan province and Ganzhou in Jiangxi province.The bacteria were isolated and cultured,and the suspected colonies were selected for Gram staining microscopy.Susceptibility test was used to detect the sensitivity and multiple drug resistance of the isolates to 14 common antibacterial drugs.Common clinical drug resistance genes were isolated by PCR amplification.Phylogenetic analysis of mcr-1 gene positive isolates was performed by multiplex PCR.【Result】 A total of 724 strains of Escherichia coli of chicken origin were isolated,including 364 in Henan province and 360 in Jiangxi province.The resistance rate of 724 isolates to tetracycline was the highest (93.65%),followed by flufenicol (87.98%),and amicacin and colistin were more sensitive (4.83% and 18.51%,respectively).96 isolates of 724 strains carried mcr-1 gene,and all of them showed multi-drug resistance,with 96.88% resistance rates to doxycycline and flufenicol.Among the 96 isolates carrying mcr-1 gene,27 carried other clinical drug resistance genes,among which 14 carried fosA3 gene,11 carried blaCTX-M-1G gene,13 carried blaCTX-M-9G gene,and 3 carried blaNDM gene.11 isolates carried both fosA3 and β-lactamase genes.Phylogenetic analysis showed that 87 isolates carrying mcr-1 gene belonged to group A,4 isolates belonged to group B1,and 5 isolates belonged to group D.【Conclusion】 There were differences in the mcr-1 gene Escherichia coli of chickens from different years and regions.mcr-1 gene positive isolates showed obvious multi-drug resistance,and some isolates carrying mcr-1 gene also carried other clinical drug resistance genes.Continuous monitoring of the prevalence of mcr-1 gene in different regions and fields was helpful to better understand the formation and spread of bacterial resistance,and then took effective prevention and control measures.

Key words: colistin; Escherichia coli; mcr-1 gene; drug resistance

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