一起空肠弯曲菌引起食源性疾病事件的病原学研究及溯源分析

Etiology analysis and source tracing of a foodborne disease outbreak caused by Campylobacter jejuni

目的 对一起食源性疾病事件进行病原菌检测,了解病原菌毒力基因携带情况并进行溯源分析。方法 对事件采集的样本经FilmArray多重PCR系统进行快速初筛,同时进行细菌分离培养鉴定。使用PCR检测技术对分离菌株进行毒力基因检测,采用16S rRNA基因序列分析与PFGE分型方法对分离菌株进行同源性分析。结果 2份患者肛拭子样本和4份食堂厨工肛拭子样本检出空肠弯曲菌,检出菌株均携带flaA、cadF、imaA、cdtA、cdtB、cdtC等毒力基因。16S rRNA基因序列分析表明6株分离菌株均为空肠弯曲菌,1株菌株与其他5株菌株分子发育距离稍远。6株菌株经PFGE分型可分为3种带型,3株菌和2株菌分别呈现同一带型,2种带型相似性为52.2%;另1株菌为另一带型,与其他菌株带型相似性仅为26.7%。结论 实验室结果表明这是一起由不同克隆株的空肠弯曲菌感染引起的食源性疾病事件。

Objective To conduct the pathogenic bacteria detection,the carriage of virulence genes and the source tracing analysis in a foodborne disease outbreak event.Methods The samples collected from the event were rapid screened by FilmArray multiplex polymerase chain reacion(PCR) system,and were conducted to bacteria culture,isolation and identification simultaneously. Real-time PCR was performed for virulence genes of isolated strains.Homologous analysis of the strains was studied using 16S rRNA gene sequence analysis and pulsed field gel electrophoresis(PFGE)molecular genotyping.Results Campylobacter jejunistrains were detected from anal swabs of 2 patients and 4canteen workers. All of the 6 Campylobacter jejuni strains carried flaA,cadF,imaA,cdtA,cdtB and cdtC virulence genes. All the strains were closely associated with Campylobacter jejuni via 16S rRNA gene sequence analysis,but the phylogenetic distance between one strain and the other 5 strains was slightly further. The results of PFGE showed that 6strains of Campylobacter jejuni could be divided into 3 PFGE patterns,3 strains and other 2 strains belonged to the same PFGE pattern respectively,with similarity of 52. 2%. The rest belonged to a different PFGE pattern,with similarity of26. 7% compared to others.Conclusion Laboratory analysis indicated that different clones of Campylobacter jejuni infection was the cause of this foodborne disease outbreak.