上海市闵行地区副溶血性弧菌分子流行病学特征分析

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.

Analysis of molecular epidemiological characteristics of Vibrio parahaemolyticus isolated in Minhang district, Shanghai

Objective To study the molecular epidemiological characteristics of Vibrio parahaemolyticus isolated from clinical and foodborne isolates collected in Minhang district, and understand the epidemic regularity. Methods 184 Vibrio parahaemolyticus isolates from food-poisoning, sporadic diarrhea patients and food samples from 2007 to 2010 were serotyped. Diplex-PCR was used to detect tdh and trh gene. 102 O3:K6 strains from clinical case and 41 strains from food samples were detected by pulsed field gel electrophoresis (PFGE). Results O3:K6 strains with tdh positive and trh negative were responsible for 88.5% (46/52) of food poisoning cases caused by Vibrio Parahaemolyticus, and O4:K8 strains with tdh positive and trh negative were responsible for the other 5 cases (9.6%). In 63 strains from sporadic diarrhea patients, O3:K6, O4:K8 and O3:KUT with tdh positive and trh negative were responsible for 60.3%(38/63), 19.0%(12/63) and 15.9%(10/63), respectively. 41 strains from food samples belonged to 9 serotypes except O3:K6 and O4:K8, and were both tdh and trh negative. PFGE typing showed that the dominant clone in food poisoning was among O3:K6 strains, and some strains isolated from food poisoning and sporadic diarrhea patients were the same molecular type. All strains isolated from food samples were unrelated with clinical cases. Conclusions There was significant difference between Vibrio Parahaemolyticus isolated from clinical and food samples in the serotype classification , virulence gene and molecular characteristics. A group of close related Vibrio Parahaemolyticus ofO3:K6 strains with tdh positive and trh negative seemed to be prevailing in Minhang.