江苏省苏州市金黄色葡萄球菌食物中毒的病原菌全基因组测序分析

Whole-genome sequencing analysis of Staphylococcus aureus in a food poisoning outbreak in Suzhou, Jiangsu Province

  • 摘要:
    目的 对江苏省苏州市高新区一起食物中毒事件进行流行病学调查和病原菌分离、鉴定及全基因组测序分析,为类似事件的预防和处理提供参考。
    方法 对病例、餐厅工作人员进行流行病学调查,对病例和餐厅工作人员的肛拭子样本、餐饮制作区环境涂抹样品及留样食品进行多病原筛查。对样品中分离培养出的病原菌进行全基因组测序分析。
    结果 通过医院就诊登记查询、现场询问开展病例搜索,共发现病例15人。15份病例样本中有14份金黄色葡萄球菌(SA)检测阳性,15份工作人员样本中有3份SA检测阳性,34份留样食品中有6份SA检测阳性。全基因组测序结果显示,6株食品分离株和13株病例分离株的序列分型(ST)型别、葡萄球菌A蛋白(SPA)分型、肠毒素基因均相同,全基因组单核苷酸多态性(wgSNP)位点差异≤5。本研究发现了SA新的ST型别——ST9159和ST9161。
    结论 本次食物中毒是由携带sebsec肠毒素基因的SA污染食物引起。食物污染及发生交叉污染的原因是食品加工操作过程不规范、生熟食品器具混用、部分菜肴常温存放时间长。应加强食品场所的卫生监督,减少类似事件的发生。

     

    Abstract:
    Objective To conduct an epidemiological investigation, isolate and identify the pathogenic bacteria, and perform whole-genome sequencing (WGS) analysis of a food poisoning outbreak in Suzhou High-tech Zone, so as to provide references for the prevention and management of similar incidents.
    Methods An epidemiological investigation was carried out on affected individuals and restaurant staff. Multi-pathogen screening was performed on rectal swab samples from affected cases and restaurant staff, as well as on environmental swab samples from food preparation areas and retained food samples. WGS was performed on the pathogens isolated from the samples.
    Results A total of 15 cases were identified through hospital visit record reviews and on-site inquiries. Of the 15 case samples, 14 tested positive for Staphylococcus aureus (SA). In addition, 3 out of 15 staff samples and 6 out of 34 retained food samples tested positive for SA. WGS results revealed that the 6 food-derived isolates and 13 case-derived isolates shared the same sequence type (ST), Staphylococcal Protein A(SPA) type, and enterotoxin gene profile, with whole-genome single nucleotide polymorphism (wgSNP) differences of ≤5. Two novel SA sequence types: ST9159 and ST9161, were also identified in this study.
    Conclusion This food poisoning outbreak is caused by contamination food with SA harbouring the seb and sec enterotoxin genes. The primary causes of contamination and cross-contamination included improper food handling practices, the use of the same utensils for raw and cooked foods, and extended storage of certain dishes at room temperature. Strengthening sanitary supervision in food handling facilities is crucial for reducing the occurrence of similar incidents.

     

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