重症监护病房耐甲氧西林金黄色葡萄球菌耐药性及基因分型研究

Drug-resistance and genotyping of methicillin-resistant Staphylococcus aureus isolated from intensive care unit

目的 对重症监护病房（ICU）耐甲氧西林金黄色葡萄球菌（MRSA）感染进行分子流行病学调查,探讨临床分离菌株的同源性,为预防和控制医院感染提供参考.方法 采用药敏纸片法（K-B法）、葡萄球菌染色体mec盒基因（SCCmec）分型及葡萄球菌蛋白质A（spa）基因分型技术对2009年11月24日-12月3日宁夏医科大学附属医院ICU、急诊ICU、烧伤ICU、呼吸ICU的MRSA感染患者、医护人员携带及周围环境中的MRSA进行药物敏感性试验和同源性分析.结果 440份样本中共分离出78株金黄色葡萄球菌,其中MRSA 62株（79.48%）,主要分离于烧伤ICU（22/62,35.48%）.SCCmec分型结果显示,50株为医院获得性MRSA（SCCmecⅢ型43株、SCCmec Ⅰ型4株、SCCmecⅡ型3株）,未分型12株.进行spa分型研究的37株MRSA中,28株医院获得性MRSA为SCCmecⅢ-t030,呈现高度的克隆一致性.结论 MRSA菌株具有多药耐药的特征,SCCmecⅢ-t030型是其主要型别,MRSA 临床株与环境株可能具有同源性.

Objective To investigate drug resistance and genotypes of methicillin-resistant Staphylococcus aureus （MRSA） isolated from intensive care unit （ICU）. Methods MRSA strains were isolated from patients, medical staff and environment of hospital ICUs. Disk diffusion （K-B method） was used for drug resistance testing; Staphylococcal cassette chromosome mec （SCCmec） and Staphylococcal protein A （spa） typing methods were used for genotyping and identifying the homology. Results There were 78 strains of Staphylococcus aureus isolated including 62 isolates of MRSA, which were mainly from the burn ICU （22, 35.48%）. Among 62 MRSA strains, 50 were hospital acquired strains, in which 43 isolates were of SCCmec Ⅲ, 4 of SCCmec Ⅰ and 3 of SCCmec Ⅱ. Twelve isolates could not be typed. Twenty-eight out of 37 hospital acquired isolates were typed by spa typing as SCCmec Ⅲ-t030, which belonged to the same clone. Conclusion MRSA in ICU is multi-drug resistant and SCCmec Ⅲ-t030 is the most prevalent genotype, which indicates that clinical MRSA strains and environmental MRSA strains may be homologous.