耐甲氧西林金黄色葡萄球菌PFGE分型与医院感染暴发的分子流行病学研究

Molecular epidemiologic study on pulsed-field gel electrophoresis genotyping of methicillin-resistant Staphylococcus aureus and outbreak of nosocomial infections

目的了解医院感染耐甲氧西林金黄色葡萄球菌(MRSA)的同源性及院内流行特征,为临床控制MRSA感染、制定合适的预防控制措施提供依据。方法收集2011年6-7月全院患者各类标本中分离出的MRSA 36株,金黄色葡萄球菌鉴定采用法国生物梅里埃公司的VITEK-2全自动微生物分析系统,根据美国CLSI标准用头孢西丁K-B法确认MRSA;运用脉冲场凝胶电泳(PFGE)对医院感染MRSA进行基因分型,并进行流行病学分析。结果临床分离的36株MRSA,PFGE分型为6型8个亚型,其中以A型为主;在研究期间,NICU及ICU发生两次MRSA感染暴发。结论 MRSA在NICU及ICU易发生交叉感染;PFGE是医院感染暴发及流行病学的较好的研究手段。

OBJECTIVE To analyze the homology among different strains and epidemiologic characteristics of methicillin-resistant Staphylococcus aureus （MRSA） isolated from our hospital, so as to guide prevention and control of nosocomial infections of MRSA. METHODS A total of S. aureus strains were identified by using Biomerieux VITEK-2 automatic microbial analysis system from various specimens collected from all patients in the hospital from Jun. to Jul. 2011, then the MRSA strains were confirmed according to the CLSI standard of cefoxitin KB method. The clinical strains were typed with pulsed-field gel electrophoresis （PFGE）, and epidemiological analysis was conducted. RESULTS The 36 MRSA strains displayed 6 kinds of genotypes and 8 kinds of subtypes, which was dominated by A genotype. During this research, outbreak of MRSA infection occurred for two times in NICU and ICU. CONCLUSIONS MRSA might have a high possibility of causing cross-infection in ICU wards and NICU wards, while PFGE is a good research method for the study of nosocomial infection outbreak and its epidemiology.