China Animal Husbandry and Veterinary Medicine ›› 2024, Vol. 51 ›› Issue (2): 837-849.doi: 10.16431/j.cnki.1671-7236.2024.02.040

• Basic Veterinary Medicine • Previous Articles     Next Articles

Drug Resistance and Prevalence of Escherichia coli Isolated from Livestock and Poultry in Areas of Guangdong

LI Yafei1,4, LIANG Xiaoyun2,5, WU Liqin3, XIAO Tianan3, WANG Fuhua1,4, ZENG Zhenling2   

  1. 1. Institute of Quality Standard and Monitoring Technology for Agro-products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China;
    2. Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Guangzhou 510642, China;
    3. Guangdong Centre for Agricultural Products Quality and Safety, Guangzhou 510230, China;
    4. Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-products, Guangzhou 510640, China;
    5. Guangdong Guangzhou Baiyun Animal Health Inspection Institute, Guangzhou 510420, China
  • Received:2023-08-14 Online:2024-02-05 Published:2024-01-29
  • Contact: 国家自然科学基金(31902323);"十三五"国家重点研发计划项目(2018YFD0500300);团队启动项目(DWJJ-202204);广东省农产品质量安全风险评估重点实验室(2019年度)(2019B121203009)

Abstract: 【Objective】 The aim of this experiment was to investigate the prevalence and drug resistance of Escherichia coli (E. coli) from livestock and poultry in some areas of Guangdong, and provide reference for drug resistance prevention and control of E. coli derived from animals.【Method】 Samples of feed, drinking water and anal (cloaca) swabs of healthy animals collected from 10 farms in some areas of Guangdong in 2019 were subjected to E. coli isolation and identification, drug sensitivity test, detection of drug resistance genes and insertion sequence common region (ISCR), as well as ethnic phylogenetic analysis.【Result】 A total of 416 E. coli strains were isolated, including 78 strains from breeding pigs, 77 strains from broilers, 122 strains from laying hens and 139 strains from broilers.These strains showed the characteristics of multiple drug resistance, and the drug resistance rate of E. coli from broilers was the highest among different animal sources.79.6% (331/416) strains were resistant to 3 or more drugs, up to 13 drugs, and a total of 156 drug resistance profiles were formed.The main resistance profiles was sulfamethoxazole-trimethoprim/florfenicol/doxycycline/amoxicillin/ampicillin, accounting for 11.1%. floR gene showed the highest detection rate of 50.0%, followed by sul2 and sul3 genes, which were 44.2% and 42.5%, respectively.The detection rates of tet(X3), tet(X4) and mcr-1 genes associated with tigecycline and colistin resistance phenotypes were all lower than 10%.Insert sequence common region (ISCR) elements for ISCR1, ISCR2 and ISCR3 were present in 14.4%, 10.8% and 10.6% isolates, respectively.The coincidence rate of phenicols, sulfonamides and β-lactam resistance genes with drug-resistant strains was more than 60%, respectively.The coexistence of drug resistance genes cmlA, tetA, qnrS, blaCTX-M-9G with ISCR1, tet(X4), sul2 with ISCR2, and tet(X4), sul3, qnrS, blaSHV with ISCR3, were statistically significant (P<0.05), respectively.E. coli from different animals and ISCR-related mobile element-positive bacteria were both mainly distributed in phylogenetic group A.【Conclusion】 E. coli isolates from animals in some areas of Guangdong presented multiple drug resistance, and carried multiple drug resistance genes, as well as mobile elements ISCR.These results provided reference for understanding the drug resistance characteristics and prevalence of resistant genes in animal-derived bacteria in Guangdong province.

Key words: Escherichia coli; livestock and poultry; drug resistance; resistance genes

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