分型方法结合DL MRSA Library数据库研究MRSA医院感染

摘要

目的 探讨引发医院感染的耐甲氧西林金黄色葡萄球菌(MRSA)的抗药性、来源和分子流行病学特征.方法 采集北京同仁医院2007-2008年分离的明确致病MRSA 57株,结合K-B法、MIC法、多重PCR、自动化重复序列PCR(REP-PCR)分型平台及DL MRSA Library数据库信息比对来分别描述MRSA的抗生素耐药表型、潘顿-瓦伦丁杀白细胞素基因(pvl)携带、Stapblococcal cassette chromosome mec(SCCmec)分型及REP-PCR分型情况.结果 根据对利福平、克林霉素、左氧氟沙星、复方磺胺甲恶唑的耐药差异,57株MRSA被分为(a～f型)6种抗生素耐药表型.SCCmecⅢ和SCCmecⅡ型MRSA分别为52株和3株,占研究菌株的91.23%和5.26%,仅1株MRSA pvl阳性.通过自动化REP-PCR分型平台,研究菌株被分为REP-A～F共6型和3株"单克隆株".REP-C型菌株数量最多(52.63%,30/57).6株REP-D型MRSA菌株中,3株分离自喉科病房.本院REP-C-SCCmecⅢ型与DL MRSA Library中的Brazilian clone-SCCmecⅢ型遗传学最接近.结论 社区相关性耐甲氧西林金黄色葡萄球菌(CA-MRSA)引起的医院感染在北京同仁医院还较罕见.REP-C-SCCmecⅢ-a型MRSA为该院医疗相关性耐甲氧西林金黄色葡萄球菌(HA-MRSA)的主要流行株,REP-D-SCCmecⅢ-d型菌株是喉癌术后医院感染的相对特有菌株.自动化REP-PCR检测平台结合DL MRSA Library数据库的方法是研究医院感染的快速、有效工具.%Objective To investigate the drug resistance,source and molecular epidemiology of methicillin-resistant Staphyloccus aureus(MRSA)causing nosocomial infection. Methods Fifty-seven pathogenic MRSA strains were isolated from Beijing Tongren Hospital during 2007 and 2008.K-B method,MIC assay,multiple PCR,automatic repetitive element sequence-based PCR(REP-PCR)typing platform and DL MRSA Library were used to identify the resistant phenotypes,Panton-Valentine leukocidin gene (pvl)and REP-PCR types of the MRSA.Results All strains were classified as 6 antibiotic resistant phenotypes(a-f)based on the resistance to rifampin,clindamycin,levofloxacin and cotrimoxazole.The MRSAs with Staphylococcal cassette chromosome mec(SCCmec)Ⅲ and SCCmec Ⅱ accounted for 91.23% (52/57)and 5.26%(3/57)of all strains,respectively.Only one strain was pvl positive.All strains were typed as REP-A-F(6 types)and three single clones by automatic REP-PCR typing platform,in which REP-C was predominant(30/57,52.63%).Three out of 6 REP-D strains were from laryngology wards.The REP-C-SCCmec Ⅲ were genetically most close to the Brazilian clone-SCCmec Ⅲ in DL MRSA Library.Conclusion s REP-C-SCCmec Ⅲ-a type are the major epidemic hospital-associated MRSA and the REP-D-SCCmec Ⅲ-d is usually isolated from patients received laryngeal surgery. Automatic REP-PCR typingplatform combined with DL MRSA Library database is an effective approach to study the nosocomial infection.