金黄色葡萄球菌食品分离株肠毒素基因分布及分型研究

Distribution of enterotoxin genes and genotyping in Staphylococcus aureus isolated from food

目的对2006—2009年上海市Staphylococcus aureus(S.aureus)食品分离株进行肠毒素基因检测和基因分型研究,以了解肠毒素基因的分布规律及S.aureus的流行特点。方法利用PCR方法检测食品中金黄色葡萄球菌肠毒素基因,包括5种传统肠毒素基因(SEA-SEE)和4种新型肠毒素基因(SEG-SEJ);利用脉冲场凝胶电泳法对49株食品分离株进行基因分型。结果本研究发现49株食品分离株中有19株含有肠毒素基因,16株含有传统肠毒素SEA和SEC,且SEC占93.8%,并检测到新型肠毒素SEG、SEI、SEJ和SEH。PFGE法基因分型显示5株菌不能被分型,其余44株可分为28个基因型,表现为基因型的多样性,且分离自不同时间的菌株具有相同的带型。结论应加强食品中S.aureus的监测分析,为其引起的食物中毒的预防和控制提供科学依据。

Objective To obtain an overview of distribution of enterotoxin genes and epidemic characteristics of S. aureus through gene testing and genotyping of isolates from food in Shanghai from 2006 to 2009. Methods Enterotoxin genes in 49 S. aureus strains from food were tested by PCR including five traditional enterotoxin genes （SEA-SEE） and four newly discovered genes （SEG-SEJ）. Pulse-field gel eleetrophoresis （PFGE） was used for genotyping. Results The total detection rate of enterotoxin genes was 38.8%. And the traditional enterotoxin genes SEA and SEC were detected, 93.8% of which belonged to SEC. The newly discovered enterotoxin genes including SEG, SEI, SEJ and SEH were also detected. The method of PFGE successfully classified 44 isolates into 28 gene types with 5 isolates indeterminable. Conclusion A wide varity of S. aureus genomic types could contaminate food and lead to food poisoning. The surveillance and ongoing monitoring ofS. aureus should be strengthened to provide scientific basis for food poisoning prevention and control.