Antimicrobial resistance characteristics,phylogenetic analysis,and pathogenicity of Escherichia coli isolated from free-Range tibetan pigs in Tibet
10.16303/j.cnki.1005-4545.2025.09.12
- VernacularTitle:西藏散养藏猪源大肠杆菌的耐药特性、系统进化与致病性分析
- Author:
Runbo LUO
1
;
Kexin LI
;
Yanan ZHONG
;
Peng SHANG
;
Sizhu SUOLANG
;
Ruibing CAO
Author Information
1. 南京农业大学 动物医学院,江苏 南京 210095;西藏农牧学院动物科学学院农业农村部西藏包虫病防治重点实验室,西藏林芝 860000
- Publication Type:Journal Article
- Keywords:
Xizang;
tibetan pigs;
Escherichia coli;
molecular characterization;
antimicrobial resist-ance;
pathogenicity
- From:
Chinese Journal of Veterinary Science
2025;45(9):1909-1917
- CountryChina
- Language:Chinese
-
Abstract:
To understand the epidemiological characteristics and antimicrobial resistance of Esche-richia coli in free-range Tibetan pig populations,fecal samples from these pigs were collected be-tween 2021 and 2023 for pathogen isolation and identification.The isolated strains underwent anal-ysis of pathogenicity categories,phylogenetic grouping,and antimicrobial susceptibility profiles,a-long with resistance gene detection and mouse pathogenicity testing.The results showed that 123 strains of E.coli were isolated from 132 fecal samples.Enteropathogenicity tests revealed that 42.28％were EAEC(52/123),7.32％were EPEC(9/123),and 3.25％were STEC/EHEC(4/123).Phylogenetic analysis indicated that 78.86％(97/123)belonged to group A,while 11.38％(14/123)belonged to group B1.Antimicrobial susceptibility tests for 22 drugs showed the highest resistance rate to amoxicillin at 98.37％(121/123),followed by sulfamethoxazole at 73.98％(91/123).Resistance rates for ampicillin,tetracycline,erythromycin,and trimethoprim ranged from 48.78％to 51.22％.Furthermore,78.86％(97/123)of the isolates were resistant to three or more antibiotics.The detection of 52 drug-resistance genes in 10 categories showed that 15 drug-resist-ance genes were detected,and the detection rate was 28.85％(15/52).Among individual resistance genes,tetA had the highest detection rate at 63.41％(78/123),followed by tetB and qnrS with de-tection rates of 48.78％(60/123)and 38.21％(47/123),respectively.This study demonstrates that EAEC is the predominant strain of E.coli in free-range Tibetan pigs,with groups A and B1 being the major phylogenetic groups.The isolates exhibited a high degree of multidrug-resistant pheno-types,and the detection rates of resistance genes were also high.E.coli carrying virulence genes cause different degrees of pathological changes in the mouse ileum.The research results have sig-nificant public health implications and provide theoretical basis for the prevention,treatment,and clinical medication of E.coli disease in Tibetan pigs.
