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目的多中心研究我国2005年苯唑西林耐药的金黄色葡萄球菌(MRSA)分子流行病学特征。方法收集2005年1—12月14个城市17家教学医院连续分离的非重复 MRSA 395株,通过多重 PCR 对 MRSA 进行葡萄球菌染色体 mec(SCCmec)分型,脉冲场凝胶电泳(PFGE)进行同源性分析。根据药敏结果、PFGE、SCCmec 型别和分布地区选出53株进行多位点序列分型(MLST)。采用PCR 检测毒素基因。结果 395株 MRSA 中,SCCmecⅢ型243株、占61.5%,不能分型菌株96株、占24.3%,Ⅱ型56株、占14.2%;沈阳 SCCmecⅡ型占60.7%(17/28),远高于其他地区(0～42.9%)。PFGE 共有24种分型,42种亚型,其中 A 型占50.1%,为12个城市13家医院所共有,R 型占23.5%,存在于8个城市9家医院。MLST 共有6种分型,其中序列分型(ST)239占75.5%,ST5占17.0%。395株 MRSA 中,pvl 基因检出率为2.5%。结论我国 MRSA 主要获得Ⅱ型、Ⅲ型 SCCmec 基因,SCCmec 的分布有地区差异。一些地区发生 MRSA 的暴发,并且地区问发生流行克隆的传播。有些流行克隆可能来源于某些世界流行克隆株的传播。
Objective To study the molecular epidemiological characteristics of oxacillin-resistant Staphylococcus aureus (MRSA) in China in 2005. Methods Non-repetitive MRSA 395 strains isolated from 17 teaching hospitals in 14 cities from January to December in 2005 were collected. Staphylococcus aureus mec (SCCmec) typing and pulsed-field gel electrophoresis (PFGE) Source analysis. According to the susceptibility results, 53 strains of PFGE, SCCmec were selected for multilocus sequence typing (MLST). Toxin genes were detected by PCR. Results Among the 395 MRSA strains, 243 strains were SCCmec Ⅲ (61.5%), 96 strains were non-typed strains (24.3%) and 56 strains (56.2%), accounting for 60.7% (17/28) Other regions (0 ~ 42.9%). PFGE has 24 subtypes and 42 subtypes, of which A type accounts for 50.1%, shared by 13 hospitals in 12 cities, R type accounts for 23.5% and exists in 9 hospitals in 8 cities. There are 6 genotypes in MLST, of which 239 (ST) 239 accounts for 75.5% and ST5 accounts for 17.0%. In 395 strains of MRSA, the detection rate of pvl gene was 2.5%. Conclusion The main type Ⅱ and type Ⅲ SCCmec genes were obtained from MRSA in China. There were regional differences in the distribution of SCCmec. An outbreak of MRSA occurred in some areas and a spread of epidemic cloning occurred in the area. Some popular clones may have originated from the spread of some of the world’s most popular clones.