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目的分析上海市闵行地区副溶血性弧菌临床和食源性分离株的分子流行病学特征,了解本地区副溶血性弧菌的流行规律。方法对2007—2010年临床来源菌株(食物中毒患者和散发腹泻病例)以及食源性样品中分离的184株副溶血性弧菌进行血清分型、耐热直接溶血素基因(tdh)和耐热相关溶血素基因(trh)检测。对102株临床来源O3:K6型菌株及41株食源性样品来源株,应用脉冲场凝胶电泳(PFGE)进行分子分型和溯源分析。结果在调查的52起副溶血性弧菌引起的食物中毒事件中,tdh阳性、trh阴性的O3:K6血清型引起的有46起(88.5%),tdh阳性、trh阴性的O4:K8血清型引起的有5起(9.6%)。在散发腹泻病例中,tdh阳性、trh阴性的O3∶K6、O4∶K8和O3∶KUT菌株分别占60.3%(38/63)、19.0%(12/63)和15.9%(10/63)。41株食源性样品株分属9种O血清群,未见O3∶K6和O4∶K8血清型菌株,而且tdh和trh均为阴性。PFGE聚类分析显示闵行地区食物中毒O3∶K6分离株中存在着遗传关系密切相关的优势流行克隆,散发腹泻患者O3∶K6分离株中存在着与食物中毒优势株相同谱型,而所有食源性样品分离株与临床患者来源株亲缘关系都较远。结论临床和食源性样品来源的副溶血性弧菌在血清分型、毒力基因和分子特征等方面存在显著差异,一大群遗传关系密切、tdh阳性、trh阴性的O3∶K6血清型菌株在闵行地区呈优势流行。
Objective To analyze the molecular epidemiology of clinical and food-borne Vibrio parahaemolyticus in Minhang, Shanghai, and to understand the prevalence of Vibrio parahaemolyticus in this area. Methods Serotypes of 184 Vibrio parahaemolyticus isolates from clinical isolates (food-poisoning cases and diarrhea cases) and food-borne samples from 2007 to 2010 were genotyped, tdh (heat-resistant hemolysin) and heat-resistant Related hemolysin gene (trh) test. 102 strains of O3: K6 strains and 41 strains of food-sourced samples were obtained, and their molecular typing and traceability were analyzed by pulsed-field gel electrophoresis (PFGE). Results Of the 52 food poisonings caused by V. parahaemolyticus investigated, 46 (88.5%), tdh-positive, and trh-negative serotype O4: K8 were caused by tdh-positive and trh-negative serotype O3: Caused by 5 (9.6%). Among cases of diarrhea, tdh-positive and trh-negative O3: K6, O4: K8 and O3: KUT strains accounted for 60.3% (38/63), 19.0% (12/63) and 15.9% (10/63), respectively. The 41 food-derived sample strains belonged to 9 serogroups, no O3: K6 and O4: K8 serotype strains were found, and both tdh and trh were negative. PFGE cluster analysis showed that there was a prevalence of epidemic clones in O3: K6 isolates of food poisoning in Minhang area. Among O3: K6 isolates from patients with diarrhea, the same pattern existed in the O3: K6 isolates as the dominant strains of food poisoning. However, Sexual samples isolates and clinical patients from distant relatives. Conclusions There are significant differences in serotyping, virulence genes and molecular characteristics of Vibrio parahaemolyticus from clinical and food samples. A large group of O3: K6 serotype strains with close genetic relationship, tdh positive and trh negative, The area is prevalent.