北京市朝阳区食物中毒相关金黄色葡萄球菌病原学分析

Etiological analysis of Staphylococcus aureus associated with food poisoning in Chaoyang district of Beijing

目的了解2017年北京市朝阳区11株食物中毒相关金黄色葡萄球耐药性、耐药基因、毒力基因及分子分型。方法依据GB4789.10-2016对甲、乙饭店留样食品、餐具及厨师手涂抹样品进行金黄色葡萄球菌分离鉴定;荧光定量PCR法检测耐药基因mecA、vanA与毒力基因sea、seb、sec、sed、see;纸片法与微量肉汤稀释法进行药物敏感性试验;脉冲场凝胶电泳(pulsed field gel electrophoresis,PFGE)进行溯源分析。结果甲、乙饭店留样食品、餐具涂抹及厨师手涂抹样品共检出11株金黄色葡萄球菌。耐药基因mecA、vanA与毒力基因sea、seb、sec、sed、see均未检出。检出菌株对青霉素100%耐药,四环素、氯霉素耐药率分别为27.3%、9.09%,未发现耐甲氧西林金黄色葡萄球菌株。PFGE分型显示,甲饭店餐具涂抹菌株、手涂抹菌株及乙饭店所有菌株可为3种带型。结论甲乙饭店分别为两起由金黄色葡萄球菌引起的食物中毒事件,皆为携带菌株的厨师污染餐具及食品引起,菌株具有较高耐药性。

Objective To understand the drug resistance,drug resistant gene,virulent gene and molecular typing of 11 food poisoning-related Staphylococcus aureus in Chaoyang district of Beijing in 2017.Methods The samples of residue food,tablewares and food processing staff’s hands from restaurant A and B were collected for the isolation and identification of Staphylococcus aureus according to GB 4789.10-2016.The drug resistant genes mecA、vanA and virulent genes sea、seb、sec、sed、see were detected by real-time PCR.The drug sensitivity was tested by using K-B assay and broth microdilution according to the clinical and laboratory standard institute(CLSI).Pulse field gel electrophoresis(PFGE)was applied to the source-tracking of this food poisoning accident.Results Eleven strains of Staphylococcus aureus were detected in the samples of residue food,tablewares and food processing staff’s hands in restaurant A and B.The drug resistant genes mecA、vanA and virulent genes sea、seb、sec、sed、see were not detected.The resistant rate to penicillin was 100%,tetracycline and chloramphenicol were 27.3%and 9.09%.Methicillin-resistant Staphylococcus aureus was not found.PFGE typing results revealed that the strains isolated from tableware’s in restaurants A,food processing staff’s hands in restaurants A and all strains isolated from restaurants B were grouped into 3 groups.Conclusion The food poisoning in restaurants A and B were caused by different Staphylococcus aureus which carried by food processing staff contaminated tablewares and food.Those strains showed higher drug resistance.