副溶血性弧菌食源性疾病分离株的血清型、毒力基因及PFGE分析

Analysis of serotype,virulence genes and PFGE molecular typing in Vibrio parahaemolyticus isolates in foodborne disease

目的了解义乌市副溶血性弧菌食源性疾病分离株的主要流行血清型和相关生物学特征。方法对2011年-2013年食源性疾病事件中检出的副溶血性弧菌,采用血清凝集试验进行血清分型;通过PCR方法对直接耐热溶血素(TDH)的基因(tdh)和耐热直接相关溶血素(TRH)的基因(trh)进行检测;对副溶血性弧菌分离株进行脉冲场凝胶电泳(PFGE)分型。结果在检出的46株副溶血性弧菌中,腹泻肛拭来源有44株,O3∶K6型菌株有43株;O4∶KUT型菌株1株。食品留样分离株共2株,2株血清型为O3∶K6。所有分离株tdh均阳性,阳性率100%。所有菌株均未检出trh基因。经脉冲场凝胶电泳分析,46株副溶血性弧菌共得到25个带型。同一起食源性疾病副溶血性弧菌分离株经脉冲场凝胶电泳得到的指纹图谱完全相同。结论引起义乌市食源性疾病的副溶血性弧菌株,是主要以携带tdh基因的O3∶K6型菌株。PFGE分型能显示菌株间的亲缘关系,为流行病学追踪传染源提供依据。

Objective To understand the predominant serotype and related biological characteristics of Vibrio parahaemolyticus isolates in foodborne disease in Yiwu. Methods Vibrio parahaemolyticus isolates in foodborne disease were detected from 2011 to 2013. The serotype were detected by serum agglutination test. Thermostable direct hemolysin（ TDH） gene（ tdh） and heat directly related hemolysin（ TRH） gene（ trh） were detected by PCR method. All strains were typed by pulsed- field gel electrophoresis（ PFGE）. Results Among 46 Vibrio parahaemolyticus strains,44 strains were from diarrhea rectal swab sources; the bacterial strains of O3∶K6 were 43,and 1 strain serotype was O4∶KUT. And two isolates were from food source,the two serotype were O3∶K6. All isolates were tdh gene positive,the positive rate of tdh gene was 100%. All strains were not detected trh genes. 46 strains of Vibrio parahaemolyticus were divided into 25 patterns by PFGE. Same PFGE patterns were detected from the same foodborne disease. Conclusion The O3∶K6 Vibrio parahaemolyticus with tdh gene was the main strains from foodborne disease in Yiwu. PFGE typing can show the genetic relationships among strains and provide the basis for epidemiological tracing the source of infection.