一起多血清型副溶血性弧菌聚集性腹泻事件的病原分析

Pathogen analysis of a multi-serotype Vibrio parahaemolyticus aggregation diarrhea event

目的了解一起聚集性腹泻事件中副溶血性弧菌的主要血清型、生物学特征的相关性和同源性,为流行病学调查提供实验室依据。方法采用流行病学方法调查聚集性腹泻事件,参照WS271-2007附录B3分离检测病原菌,聚合酶链反应测定毒力基因,最小抑菌浓度测定17种药物敏感度,脉冲场凝胶电泳(PFGE)进行基因分型,BioNumerics软件进行聚类分析。结果该次事件分离得到21株副溶血性弧菌,其中20株来源于患者肛拭样品,1株分离自餐厅从业人员肛拭样品;以O3:K6 15株(71.43%)为优势血清型,均为耐热直接溶血素、toxRS-new、orf8-up阳性,耐热直接溶血素相关溶血素、toxRS-old阴性;O4:K8 4株(19.05%);O3:KUT和O4:KUT均仅有1株,各占4.76%。药敏试验结果基本一致,对两种药物(氨苄西林、头孢唑啉)100%耐药。PFGE分型按100%相似度分为7个型别。结论该次聚集性腹泻事件是以O3:K6血清型为主的不同克隆株副溶血性弧菌混合感染所致。

Objective To understand the main serotypes,biological characteristics,correlation and homology of Vibrio parahaemolyticus in an aggregated diarrhea event,and to provide laboratory evidence for epidemiological investigation.Methods Epidemiological investigation of clustering diarrhoea events was conducted according to WS271-2007appendix B3to isolate and detect pathogenic bacteria.Polymerase chain reaction(PCR)was used to detect virulence genes,minimum inhibitory concentration was used to detect17kinds of drug sensitivity,pulse field gel electrophoresis(PFGE)was used for genotyping,and BioNumerics software was used for cluster analysis.Results A total of21strains of Vibrio parahaemolyticus were isolated from this accumulation event,wherein20strains from the samples of patients′anus swabs and the other one from the Restaurant worker′s.Serotype O3:K6(15strains,71.43%)was predominant,with tdh,toxRS-new,orf8-up positive and trh,toxRS-old negative.The serotypes O4:K8was found in4strains,accounting for19.05%,O3:KUT and O4:KUT had only1strain accounting for4.76%aech.The susceptibility test results were similar,the resistance to two drugs(Ampicillin,Cefazolin)in all strains were100%.PFGE typing was divided into7types according to100%similarity.Conclusion This accumulation event was caused by co-infections of Vibrio parahaemolyticus with different clonal strains mainly composed of serotype O3:K6.