Molecular characteristics of Escherichia coli strains producing Shiga toxin 2e subtype from different sources
10.3760/cma.j.cn112309-20210329-00099
- VernacularTitle:不同来源产志贺毒素2e亚型大肠埃希菌分子特征分析
- Author:
Xi YANG
1
;
Yanyu PAN
;
Qian LIU
;
Lijiao CAO
;
Xiangning BAI
;
Yanwen XIONG
Author Information
1. 中国疾病预防控制中心传染病预防控制所，传染病预防控制国家重点实验室，北京 102206
- Keywords:
Shiga toxin-producing Escherichia coli;
Shiga toxin 2e;
Whole-genome sequencing
- From:
Chinese Journal of Microbiology and Immunology
2021;41(10):757-763
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To understand the molecular characteristics of Escherichia coli producing Shiga toxin 2e subtype isolated from different sources in China. Methods:Three human-derived, 13 animal-derived and eight food-derived stx2e-positive Escherichia coli strains which were isolated during 2012 to 2018 were analyzed by antimicrobial susceptibility testing and whole genome sequencing. The stx subtype, serotype, multi-locus sequence type, virulence genes and antimicrobial resistance genes of each strain were determined by whole genome sequences. The phylogenetic relationship and genetic composition of Shiga-toxin prophage were explored. Results:Twenty-four stx2e-STEC strains were typed into 19 O∶H serotypes and 19 sequence types (STs). Each strain carried at least one kind of antimicrobial resistance gene and 19 out of 24 strains were resistant to at least one kind of antimicrobials. Three human-derived strains were heterogenous in serotypes and STs, but there were several animal and food-derived strains shared the same serotype or ST with human strains and showed close relationship in the phylogenetic analysis. The sequences of stx2e among all strains were highly conserved (similarity >99.7%), but there were significant differences in the size and the gene composition of Shiga toxin prophage genome. Conclusions:This is report about the characteristics of rare human-derived Stx2e-STEC strains in China. Comparing human isolates with animal-and food-derived strains, it indicates that Stx2e-STEC strains are highly genetic diversity and have the potential to infect humans.
