Typing methods and DL MRSA Library database in study of MRSA causing nosocomial infection / 中华临床感染病杂志

ABSTRACT

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.