三株社区获得性耐甲氧西林金黄色葡萄球菌的基因分型研究

Genetic types of three community-acquired methicillin-resistant Staphylococcus aureus isolates

目的了解西南地区社区获得性耐甲氧西林金黄色葡萄球菌（CA-MRSA）流行株的基因特征。方法用葡萄球菌盒式染色体（SCCmec）多重PCR分型技术、葡萄球菌A蛋白基因（spa）分型技术和多位点测序分型（MLST）技术对3株分离自临床的CA-MRSA（s35301、s29635、s19165）进行基因分型，并检测其杀白细胞毒素（PVL）基因。结果3株MRSA的mecA基因（147bp）全部为阳性扩增，还同时扩增出750bp左右的片段，该产物经测序后证实为SCCmecⅣa型。spa分型：s35301、s29635为t437，s19165为t008。MLST分型：s35301、s29635为ST59型，s19165为ST8型。s19165、s35301 PVL基因扩增阳性，s29635 PVL基因扩增阴性。结论西南地区分离到CA-MRSA ST8-t008克隆株及ST59-t437克隆株。应注意控制CA-MRSA感染及传播。

Objective To investigate the genetic features of the community-acquired methicillinresistant Staphylococcus aureus （CA-MRSA） prevalent in West China. Methods Three CA-MRSA isolates obtained in Chengdu, Sichuan, underwent SCCmec （Staphylococcal Cassette Chromosome mec）muhi-PCR, Staphylococcal protein A （spa） typing and multi-locus sequence typing （MLST） method, and their Panton- Valentine leucocidin （PVL） gene was also detected. Results All 3 CA-MRSA isolates were positive of mecA gene （147 bp）, and the other PCR product of 750 bp was confirmed to be type Ⅳa SCCmec. Spa typing showed that the MRSA strains s29635 and s35301 were typed as t437, and the strain s19165 was typed as t008. MLST showed that the MRSA strains s29635 and s35301 were typed as ST59, and the strain s19165 was typed as ST8. The strains s19165 and s35301 were all positive for PVL gene, and the strain s29635 was negative for PVL gene. Conclusion CA-MRSA clones ST8-t008 and ST59-t437 have been isolated in West China.