一起金黄色葡萄球菌食物中毒检测与分析

Detection and analysis of a food poisoning case caused by Staphylococcus aureus

目的查明食物中毒致病菌,分析菌株间的亲缘关系与毒力,为食物中毒诊断提供依据。方法致病菌分离采用国家标准和文献方法;金黄色葡萄球菌鉴定采用仪器法;同源性分析采用脉冲肠凝胶电泳法;肠毒素检测采用PCR法;药敏试验采用VITEK 2 Compact法。结果从22份标本中检出12株金黄色葡萄球菌,阳性检出率为54.55%;检出SEa、SEb、SEd、SEe传统肠毒素基因4种和SEh、SEj新型肠毒素基因2种;食品株与患者株金黄色葡萄球菌的脉冲肠凝胶电泳带型一致,具有高度同源性;菌株对大多数常用抗生素敏感。结论本起食物中毒由金黄色葡萄球菌及其肠毒素污染鸡肉卷所致;菌株携带多种肠毒素基因,致病性较强;鸡肉卷与患者检出的金黄色葡萄球菌脉冲肠凝胶电泳显示其来源为同一克隆群,从分子生物学上证明了食物中毒病原菌的相关性。

Objective To identify the pathogenic bacteria causing food poisoning,analyze the relationship and the virulence among the tested strains,so as to provide basis for a clear diagnosis of food poisoning events. Methods A variety of food poisoning pathogens were isolated by GB method and methods according to published literature. Staphylococcus aureus were identified using the instrument method. Pulsed-field gel electrophoresis（ PFGE） was conducted for clustering analysis of the identified isolates.Enterotoxin was detected by PCR. Drug sensitivities were tested using VITEK 2 Compact method. Results 12 S. aureus isolates were detected from 22 samples,with the detection rate of 54. 55%. The results of PCR showed that isolates harbored 4 kind of traditional enterotoxin genes of SEa,SEb,SEd,SEe and 2 kind of novel enterotoxin genes SEh and SEj. The PFGE band type of patients strains was consistent with that of food borne strains,which were highly homologous. Strains were sensitive to most commonly used antibiotics. Conclusion The food poisoning was caused by chicken rolls contaminated with Staphylococcus aureus and its enterotoxin; strains carry various enterotoxin genes with strong pathogenicity. Isolates from patients and food were highly homologous according to PFGE results,proving the relevance of food borne pathogens from the aspect of molecular microbiology.