广州市白云口岸航空食品中金黄色葡萄球菌凝固酶基因分型及肠毒素基因研究

目的对2013—2015年从广州市白云口岸航空食品中分离的金黄色葡萄球菌进行基因分型研究,为食源性金黄色葡萄球菌分子溯源提供基础数据。方法以血浆凝固酶和肠毒素为目标基因,采用聚合酶链式反应(PCR)方法对9株金黄色葡萄球菌进行基因分型,其中6株为航空食品分离株,1株为配餐车间大门手拭分离株,2株为标准菌株。肠毒素基因检测包括5种传统肠毒素基因(sea、seb、sec、sed、see)和6种新型肠毒素基因(ser、seg、seh、sei、sej、sep)。结果 6株航空食品分离株的血浆凝固酶基因扩增分型结果为2个PCR型,酶切后得3种亚型;肠毒素基因检测结果显示有2株航空食品分离株含有肠毒素基因,检出率为33.3%(2/6),检出的基因为2种传统肠毒素基因(sec、sed)和4种新型肠毒素基因(ser、seg、sei、sej),均同时携带2种以上肠毒素基因。结论血浆凝固酶基因扩增分型结果显示,不同时间、不同采集地点存在相同的基因型,提示金黄色葡萄球菌存在交叉污染的可能性;航空食品分离株共检出6种肠毒素基因,提示金黄色葡萄球菌基因型多样性,应加强其他新型肠毒素基因检测。

Research on coagulase genotyping and enterotoxin genes of Staphylococcus aureus isolated from airline food samples in Guangzhou Baiyun Airport

Objective To provide basic data for molecular tracing of foodborne Staphylococcus aureus by genotyping of isolates from airline food in Baiyun Airport during 2013-2015. Methods Foodborne Staphylococcus aureus isolates were identified through polymerase chain reaction (PCR) method targeting coagulase gene and enterotoxin genes,the enterotoxin genes included five traditional enterotoxin genes(sea, seb, sec, sed, see)and six newly discovered genes(ser, seg, seh, sei, sej, sep). Results Six Staphylococcus aureus strains isolated from airline food were separated into two genotypes and three subtypes according to coagulase gene. The traditional enterotoxin genes (including sec and sed) and the newly discovered enterotoxin genes(including ser, seg, sei and sej)were detected from two Staphylococcus aureus strains isolated from airline food. Conclusion The result of the genotyping of coagulase gene displayed the same genotypes existing in different time and different collection sites, suggesting the maximum possibility of cross contamination of Staphylococcus aureus. Six strains of Staphylococcus aureus isolated from airline food were tested for 11 enterotoxin genes, and 2 isolates contained enterotoxin gene isolated from airline food, suggesting that Staphylococcus aureus genotype was diversified, and should strengthen the detection of the new discovered toxin gene.