多菌型副溶血性弧菌共感染引起集中事件调查分析

Survey of a foodborne outbreak caused by multi type Vibrio parahaemolyticus

目的分析一起副溶血性弧菌(VP)集中感染事件的菌株特征,明确该起感染事件的性质。方法在2017年9月,广西某乡镇发生一起疑似食源性疾病暴发,现场采集13例患者肛拭子,分离到10株VP,利用O和K诊断血清对分离株进行玻片凝集实验分型,采用Taq Man水解探针荧光PCR检测分离株毒力相关tlh、tdh、trh和ORF8基因,并分别用NotⅠ和SfiⅠ两种酶进行脉冲场凝胶电泳(PFGE)分型,导入Bionumerics 6.6软件进行聚类分析。结果 10株VP有5种血清型,6株为O3∶K6,其余4株血清型分别为O4∶K8、O1∶KUT、O2∶KUT和O10∶K19。所有菌株tlh基因均呈阳性,而trh基因呈阴性;6株O3∶K6血清型菌株和1株O4∶K8血清型菌株tdh基因均呈阳性;其余3株tdh基因呈阴性。经Bionumerics 6.6软件聚类分析,NotⅠ和SfiⅠ酶切PFGE有8种型别,同为O3∶K6血清型的6株菌可分为4种型别。综合以上3个指标进行分析,该事件分离的10株菌中仅2株菌完全相同。结论该起集中暴发事件由多种血清、不同PFGE型别的致病和非致病性VP多菌型共感染引起。

Objective To understand the etiological characteristics of a foodborne outbreak caused by Vibrioparahaemolyticus.Methods A suspected food borne disease outbreak occurred in a township of Guangxi Zhuang autonomousregion in September 2017. Thirteen anal swabs were collected from the patients for the pathogen isolation in field survey and 10 V. parahaemolyticus strains were isolated. O and K diagnosis sera were used for the subtyping of the strains in slide agglutinationtest. Taqman fluorescent PCR was conducted to detect the four toxic gene（tlh,tdh,trh and ORF8）of V. parahaemolyticus. Theclustering analysis was performed with software Bionumerics 6.6 after pulsed field gel electrophoresis（PFGE）with restrictionendonuclease Not Ⅰ and Sfi Ⅰ respectively.ResultsThe 10 V. parahaemolyticus isolates belonged to 5 serotypes. Amongthem,6 were O3∶K6 strains,and the other 4 were O4∶K8,O1∶KUT,O2∶KUT and O10∶K19 strains respectively. All thestrains were positive for tlh gene and negative for trh gene. Six O3∶K6 strains and one O4∶K8 strain were tdh gene positive,theother strains were tdh gene negative. Clustering analysis indicated that the strains had 8 molecular types of PFGE after restrictionwith enzyme Not Ⅰ and Sfi Ⅰ respectively. And six O3∶K6 strains could be divided into 4 PFGE patterns. Comprehensive analysis of the 3 indicators showed that only 2 V. parahaemolyticus strains among the 10 isolates had the same serotype,toxicgene and PFGE pattern.ConclusionThe outbreak was caused by pathogenic or non-pathogenic V. parahaemolyticus withdifferent serotypes and PFGE patterns.