食物中毒中不同血清型副溶血性弧菌基因特征分析

目的对2起食物中毒中不同血清型的副溶血性弧菌进行基因特征分析。方法第1起食物中毒发生在2010年5月17日深圳市某食堂，感染人数20人左右，采集到病人肛拭子9份，可疑食品3份，每份样本挑取20个可疑菌落；第2起食物中毒发生在2010年7月1日深圳市某配餐中心，感染人数10人左右，采集到病人肛拭子7份，可疑食品2份，涂抹样3份，每份样本挑取10个可疑菌落。对可疑菌落分别进行盐耐受试验、生化试验和血清学鉴定。从2起食物中毒的每份样本中挑取不同血清型进行tdh、trh、GS—PCR、orf8基因检测和脉冲场凝胶电泳分析（PFGE）。结果第1起食物中毒分离到副溶血性弧菌180株，其中03：K6107株，02：K2870株，04：K34、03：K25、04：K12各1株；第2起食物中毒分离到副溶血性弧菌80株，其中03：K644株，04：K8、011：K36、011：K19各10株，01：K566株。03：K6、01：K56、04：K8、011：K36携带tdh基因，不携带砒基因，其他血清型（02：K28，04：K12，03：K25，04：K34，011：K19）均不携带tdh和f砘基因。03：K6和011：K362种血清型的GS-PCR和orf8基因阳性，其他血清型阴性。PFGE结果显示第1起食物中毒中食品和病人肛拭分离的02：K28（分别3、2株）的PFGE带型基本一致，属高度相关菌株。第2起食物中毒中病人肛拭分离的4株03：K6与卤鸡蛋盘涂抹样分离的1株03：K6PFGE带型一致。2起食物中毒的03：K6带型基本一致。来自相同样本不同血清型的副溶血性弧菌的PFGE带型不一致。结论第1起食物中毒与食用污染了副溶血性弧菌的食品有关，第2起食物中毒与污染了副溶血性弧茵的卤鸡蛋盘有关。通过血清分型和分子生物学分析，可认为相同样本中分离的不同血清型副溶血性弧菌未发现遗传学证据，为遗传不相关菌株。

Genetic characterization of different serotypes of Vibrio parahaemolyticus isolated from food poisoning cases

Objective To analyze the genetic characteristics of different serotypes of Vibrio parah- aemolyticus （ Vp ） isolated from two food poisoning outbreaks. Methods The first outbreak occurred in the canteen of an electronic company in Shenzhen on May 17, 2010. About 20 people were infected. Nine anal swabs from patients and 3 suspicious food samples were collected. Twenty suspicious colonies were selected for each sample after culture. The second outbreak occurred in a catering center in Shenzhen on July 1, 2010. About 10 persons were infected. Seven anal swabs from patients, 2 suspicious food and 3 tray swabs samples were collected. Ten suspicious colonies were selected for each sample after culture. Each suspi- cious colony was identified using salt tolerance test, biochemical test, and serotyping. Different serotyping isolates were collected from both outbreaks, and characterized by tdh, trh, GS-PCR, orf 8 gene detection and pulsed field gel electrophoresis （PFGE） analysis. Results One hundred and eighty Vp isolates werecollected from the first outbreak, of which, 107 isolates were serotype O3：K6,70 were O2：K28, 1 was O4 ：K34,1 was 03 ：K25 ,and 1 was O4：K12. Eighty Vp isolates were collected from the 2nd outbreak, of which, 44 isolates were serotype 03 ：K6, 10 were O4：K8, 10 was O11 ：K36, 10 was Oll ：K19 and 6 were O1 ： K56. All isolates of 03 ： K6, O1 ： K56,04 ： K8, O11 ： K36 were positive for tdh, while negative for trh gene detection. The other isolates of 02 ： K28,O4 ： K12,03 ： K25,O4 ： K34, and O11 ： K19 were negative for both genes. The isolates of O3 ： K6 and O11 ： K36 showed positive for both GS-PCR and off 8 gene detec- tion, while all the other isolates were negative for serotypes. PFGE analysis indicated that the PFGE pattern of 2 isolates （O2：K28） from patients were identical with 3 isolates （O2：K28） from food in the first out- break, and 4 isolates （O3：K6） from patients were identical with 1 isolate （O3：K6） from egg tray swab in the second outbreak. PFGE patterns of isolates of 03 ：K6 from both outbreaks were identical. Vp isolates from the same sample with different serotypes were unrelated. Conclusion The first food poisoning out- break was related to food contaminated by Vp and the second outbreak was related to egg tray contaminated by Vp. The serotyping and genetic data suggests that Vp with different serotypes from the same sample be- long to different elonal complex, and are unrelated isolates in genetics.