2008年广东省食物中毒副溶血弧菌分子特征研究

Molecular characteristics of vibrio parahaemolyticus isolated from food-poisoning events in Guangdong Province,2008

目的了解2008年广东省副溶血弧菌食物中毒分离株的血清分型及分子特征。方法对2008年广东省14起副溶血弧菌食物中毒事件中90株分离自病例和9株分离自相关食物的菌株进行血清分型,耐热溶血素基因(tlh)、耐热直接溶血素相关基因(trh)和耐热直接溶血素基因(tdh)PCR检测以及选取优势菌型O3∶K6和O4∶K8血清型进行ER IC-PCR分子分型。结果 90株病例来源菌株以O3∶K6(62.2%)和O4∶K8(14.4%)血清型为主,9株食物来源菌株血清型别多样,无优势菌型,且同时分离到病例及食物来源菌株的4件事件中有3起食物来源菌株的血清型与同一事件中从病例分离到的血清型不同。PCR检测发现,99株副溶血弧菌tlh基因均为阳性,trh基因均为阴性,tdh基因88株阳性,其中食物来源菌株tdh基因阳性率为11.1%(1/9),病例来源菌株tdh基因阳性率为96.7%(87/90)。选取22株O3∶K6血清型和10株O4∶K8血清型菌株(均分离自病例)进行ER IC-PCR分子分型分析,结果显示,2种血清型菌株可分为8个ER IC型别,且可区分为2类不同的聚类,这2类聚类之间的相似值为54.7%。同1起食物中毒事件中分离到的O3∶K6或O4∶K8血清型,其ER IC型别表现出多样性;而不同食物中毒事件中分离到的O3∶K6或O4∶K8血清型,部分菌株ER IC型别表现出100%的相似性。结论广东省副溶血弧菌食物中毒分离株血清型多样,同一血清型菌株存在遗传多样性,一群遗传关系密切的trh阴性、tdh阳性的O3∶K6和O4∶K8血清型为副溶血弧菌食物中毒优势菌型。

Objective To understand the molecular characteristics and serotype distribution of vibrio parahaemolyticus from food-poisoning events in Guangdong Province in 2008.Methods A total of 90 clinical and 9 food isolates from 14 food-poisoning events were sero-typed and tested by PCR for three virulence genes： thermolabile hemolysin（tlh）,thermostable direct hemolysin（tdh）,and thermostable related hemolysin（trh）.Molecular characterization of dominant serotypes（O3∶K6 and O4∶K8） in isolates was analyzed by ERIC-PCR.Results The main serotypes of the 90 clinical isolates were O3∶K6（62.2%） and O4∶K8（14.4%）,while the serotypes of the 9 food isolates presented diversity.The serotype differed between cases and food type in 3 out of the 4 events where isolates from both sources were obtained.All isolates were positive for tlh,but negative for trh.However,tdh was detected in only one food isolate（11.1%）,but in 96.7% of the 90 clinical isolates.Eight ERIC-PCR patterns were observed in the clinical isolates tested,including 22 isolates of serotype O3∶K6 and 10 of O4∶K8.Two clusters were formed among these patterns,and the similarity value between them was 54.7%.The ERIC-PCR patterns of the same serotype（O3∶K6 or O4∶K8） from the same event presented diversity,while patterns with 100% similarity can be seen in isolates from different events.Conclusion The isolates of vibrio parahaemolyticus from food-poisoning events in Guangdong presented various serotypes,and the same serotype might show genetic diversity.A group of genetically related isolates,negative for trh,positive for tdh,and of serotype O3∶K6 or O4∶K8,composed the dominant isolates.