Acta Veterinaria et Zootechnica Sinica ›› 2024, Vol. 55 ›› Issue (12): 5880-5885.doi: 10.11843/j.issn.0366-6964.2024.12.049

• Research Notes • Previous Articles    

Disinfectant Susceptibility Analysis of tet(X4)-Containing Porcine Escherichia coli

PAN Binglin1(), WANG Sinan1, YAO Guozhong2, ZHAI Ruidong1, SONG Houhui1, CHENG Changyong1,*(), LEI Lei1,*()   

  1. 1. China-Australia Joint Laboratory for Animal Health Big Data Analytics, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, Zhejiang Provincial Engineering Laboratory for Animal Health Inspection & Internet Technology, Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, Hangzhou 311300, China
    2. Yuhang Agricultural Bureau, Hangzhou 310023, China
  • Received:2023-10-24 Online:2024-12-23 Published:2024-12-27
  • Contact: CHENG Changyong, LEI Lei E-mail:xianyuren@stu.zafu.edu.cn;Lamge@zafu.edu.cn;leilei910@zafu.edu.cn

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Abstract:

This study aimed to asseess the prevalence of tet(X4)-containing E. coli, along with their antimicrobial resistance and disinfectant susceptibility profiles, as well as the presence of disinfectant resistance genes, in E. coli strains isolated from pig farms. A total of 440 pig fecal samples were collected and analyzed from pig farms located in Hangzhou, Zhuji, Zhoushan, within Zhejiang province. The presence of tet(X4) and disinfectant resistance genes was determined by PCR. Strain clustering was performed through Enterobacterial repetitive intergenic consensus (ERIC)-PCR, and species identification was confirmed using Sanger sequencing of the 16S rRNA gene. The phenotype of antimicrobial susceptibility and disinfectant resistance were exanimated using microdilution broth method. The results revealed that 117 tet(X4)-positive E. coli strains were isolated from samples collected across the three cities in Zhejiang province, with proportions ranging from 24.0% to 29.5%. These strains exhibited 100% resistance to ampicillin, amoxicillin/clavulanate, florfenicol, tigecycline, but remained sensitive to colistin and meropenem. Notably, the minimum inhibitory concentration (MIC) of sodium hypochlorite and potassium hydrogen peroxymonosulfate were higher than other disinfectant, reacing half of their working concentrations. Compared to ATCC 25922, only a few strains displayed higher MICs for hydrogen peroxide, peracetic acid, chlorhexidine acetate, chlorhexidine, benzalkonium bromide solution than the standard strains. Of note, 92.3% of isolates showed higher MICs for benzalkonium bromide than ATCC 25922. The predominant disinfectant resistance genes in tet(X4)-carrying E. coli were sugE(c), qacF and qacEΔ1, with detection rates of 100%, 25.6%, 11.1%, respectively. ERIC clustering showed that the 117 strains were mainly divided in to 9 groups. The study underscore the multidrug resistance observed in tet(X4)-containing E. coli strains across the three cities. While many of these strains harbored disinfectant resistance genes, they were sensitive to working concentration of tested disinfectant. Consequently, pig farms can make informed decisions regarding disinfectant selection to mitigate the spread of multi-drug resistance bacteria.

Key words: tet(X4), E. coli, antimicrobial resistance, disinfectant resistance

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