209株不同来源空肠弯曲菌分子特征分析

Molecular characterization of 209 Campylobacter jejuni strains from different source

目的应用多位点序列分型技术从分子水平分析不同来源的空肠弯曲菌的流行状况与特征,研究菌株间的亲缘关系和进化特征。方法本研究以2014-2015年分离自上海市浦东新区11个腹泻监测点的腹泻粪便、本辖区5个禽流感监测点的禽类养殖环境样本以及生禽肉食品中分离到的209株空肠弯曲菌为研究对象,选取7个管家基因进行测序分析,获得序列型(STs型),应用Bionumerics软件绘制进行溯源和遗传进化分析。结果209株分离株共分成了110种序列型,归属25种同源复合体,在144株人源株中,归属ST-353同源复合体菌株最多,占比16.7%,禽类养殖环境分离到的56株菌株归属ST-21同源复合体菌株最多,占比30.4%。遗传进化分析显示,209株菌株分为主要的5个彼此独立的聚类簇。结论上海市浦东新区的腹泻病人分离株与禽类株有着较为密切的关系,禽类是人感染空肠弯曲菌的重要传染源。

We discuss the application of MLST method for C.jejuni molecular tracing,extensively analyze the prevalence of C.jejuni from various sources at the molecular level,estimate the polymorphisms between stains,based on 209 C.jejuni strains isolated from diarrhea stool specimens obtained from 11 diarrhea sentinel hospitals,smear swabs collected form five poultry farms and raw foods.The housekeeping genes were amplified and sequenced.The nucleotide sequences were combined to sequence types (STs).Finally,BioNumerics 7.1 was used to construct the phylogenetic trees and cluster plots.The genetic polymorphism and evolution of C.jejuni were demonstrated based on the software’s analysis graph.The results showed that a total of 209 stains were classified into 110 STs by multilocus sequence typing and could be assigned to 25 Clonal Complex (CC),including 2 novel STs.The most prevalent human source CC was ST-353 (16.7%).The most prevalent poultry source CC was ST-21 (30.4%).The Neighbor Joining tree diagram showed that 209 isolates were separated into five groups.In conclusion,the analysis of genetic relationship between human and poultry has shown a close relationship between isolates from human and poultry,poultry were the most important source for human C.jejuni infections.