2014—2022年北京市肠道门诊分离的肠出血性大肠埃希菌分子分型特征分析

Molecular characteristics of enterohemorrhagic Escherichia coli isolated from instestinal clinics in Beijing,2014-2022

目的 了解北京市肠出血性大肠埃希菌(enterohemorrhagic Escherichia coli,EHEC)分子特征及流行趋势。方法 收集2014—2022年北京市肠道门诊分离到的肠出血性大肠埃希菌,通过药敏试验及全基因组测序及数据分析,以了解病原的药物敏感性及分子特征。结果 共收集到14株EHEC,其中4株为多耐药菌株;多位点序列分型(multi-locus sequence type, MLST)分析ST11型占比最高(5/14);血清分型O157:H7占比最高(6/14);全基因组单核苷酸分型(whole genome single nucleotide polymorphism, wgSNP)结果显示6株O157:H7菌株分成一簇,其他菌株分成一簇;14株北京分离到的EHEC和美国国家生物技术信息中心(NCBI)网站下载的678株中国及周边国家分离的大肠埃希菌全基因组数据wgSNP分型,没有形成明显的地域性聚集,均以散发分布为主。结论 EHEC仍是北京市肠道传染病重要的病原菌,需要进一步加强EHEC监测。

Objective To understand the molecular characteristics of enterohemorrhagic Escherichia coli(EHEC)and the trend in the prevalence in Beijing.Methods Isolated EHEC stains from the intestinal clinics in Beijing from 2014 to 2022 were collected.The susceptibility test,whole genome sequencing and data analysis were used to understand the susceptibility and molecular characteristics of the pathogen.Results A total of 14 EHEC strains were collected,including 4 multi-drug resistant strains.The multilocus sequence type(MLST)analyses showed that ST11 had the highest proportion(5/14);The proportion of O157:H7 in serum typing was the highest(6/14).The whole genome single nucleotide polymorphism(wgSNP)showed that six O157:H7 strains formed one cluster,while the other strains formed another cluste.For the wgSNP typing,the 14 EHEC strains isolated in Beijing and downloaded data of 678 strains of Escherichia coli isolated from China and surrounding countries showed no significant regional clustering,and were mainly distributed sporadically.Conclusions EHEC stains were still the important pathogens of gastrointestinal infectious diseases in Beijing and active surveillance for EHEC should be strengthened.