Prevalence and molecular characterization of Shiga toxin-producing Esch-erichia coli in domestic goats in the Chengkou District of Chongqing
10.3969/j.issn.1002-2694.2025.00.073
- VernacularTitle:重庆城口地区家养山羊携带产志贺毒素大肠埃希菌情况及其分子特征分析
- Author:
Jing-jing PENG
1
;
Bin HU
;
Xi YANG
;
Yi LI
;
Hai HUANG
;
Wen-shuang LIU
;
Yu MENG
;
Li-jun WANG
;
Yan-wen XIONG
;
Yi YUAN
;
Pei-bin HOU
Author Information
1. 山东第二医科大学公共卫生学院,潍坊 261053
- Publication Type:Journal Article
- Keywords:
Shiga toxin-producing Escherichia coli;
Shiga toxin 2k subtype;
serotyping;
drug resistance;
whole genome sequencing
- From:
Chinese Journal of Zoonoses
2025;41(5):529-536
- CountryChina
- Language:Chinese
-
Abstract:
This study investigated the infection status,drug resistance,and molecular characteristics of Shiga toxin-producing Escherichia coli(STEC)in domestic goats in Chengkou county,Chongqing.In August 2023,283 fecal samples were collected from households in Chengkou county.After enrichment with EC broth and inoculation onto selective media,samples that tested positive for stx1/stx2 were selected for further isolation.The positive strains were investigated with antimicrobial susceptibility testing and whole genome sequencing.According to the whole genomic sequences,the stx subtypes,serotypes,multi-locus sequence types,virulence genes,drug resistance genes,and phylogenetic relationships of the STEC strains were analyzed.Forty-six strains of STEC were isolated from 283 goat fecal samples,thus resulting in a detection rate of 16.25%.The 46 STEC strains were categorized into 12 O∶H serotypes,among which O76∶H19 and O8∶H7 predominated,each represented by 9 strains.Five STEC strains were identified as serotype O157∶H7.The 46 STEC strains were categorized into 11 sequence types(STs),among which ST675 and ST196 predominated,each represented by nine strains,accounting for a 19.57%proportion.The strains were categorized into 7 stx subtypes,among which stx1c(26/46,56.52%),followed by stx2k(9/46,19.57%)predominated.All nine Stx2k-STEC strains were identified as serotype O8∶H7 and sequence type ST196.In antimicrobial susceptibility testing,2 STEC strains were resistant to ampicillin,one strain was resistant to ampicillin/sulbactam,one strain was resistant to cefazolin,and one strain was resistant to cefoxitin.Nine Stx2k-STEC strains were found to carry the beta-lactam resistance gene blaEC-18.Antimicrobial sensitivity tests revealed that the nine Stx2k-STEC strains were sensitive to all 15 tested antibiotics.Moreover,phylogenetic analysis indicated that the 9 Stx2k-STEC strains were remarkably similar but showed high genetic diversity with respect to that of the Stx2k-STEC strains isolated from other regions in China.Goatsare an important animal reservoir for STEC in theChengkou district of Chongqing,and novel sequence type Stx2k-STEC strains distinct from those found in other regions of China were identified in this region.
