Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
Antimicrob Agents Chemother. 2010 May;54(5):1842-7. doi: 10.1128/AAC.01563-09. Epub 2010 Feb 22.
The incidence of methicillin-resistant Staphylococcus aureus (MRSA) has been increasing yearly at Peking Union Medical College Hospital (PUMCH). In order to understand the molecular evolution of MRSA at PUMCH, a total of 466 nonduplicate S. aureus isolates, including 302 MRSA and 164 methicillin-susceptible (MSSA) isolates recovered from 1994 to 2008 were characterized by staphylococcal cassette chromosome mec (SCCmec) typing, spa typing, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). The 302 MRSA isolates were classified into 12 spa types and 9 sequence types (STs). During the years from 1994 to 2000, the most predominant MRSA clone was ST239-MRSA-III-spa t037. Since 2000, ST239-MRSA-III-spa t030 has rapidly replaced t037 and become the major clone. Another clone, ST5-MRSA-II-spa t002 emerged in 2002 and constantly existed at a low prevalence rate. The 164 MSSA isolates were classified into 62 spa types and 40 STs. ST398 was the most common MLST type for MSSA, followed by ST59, ST7, ST15, and ST1. Several MSSA genotypes, including ST398, ST1, ST121, and ST59, were identical to well-known epidemic community-acquired MRSA (CA-MRSA) isolates. MLST eBURST analysis revealed that the ST5, ST59, and ST965 clones coexisted in both MRSA and MSSA, which suggested that these MRSA clones might have evolved from MSSA by the acquisition of SCCmec. Two pvl-positive ST59-MRSA-IV isolates were identified as CA-MRSA according to the clinical data. Overall, our data showed that the ST239-MRSA-III-spa t037 clone was replaced by the emerging ST239-MRSA-III-spa t030 clone, indicating a rapid change of MRSA at a tertiary care hospital in China over a 15-year period.
耐甲氧西林金黄色葡萄球菌（MRSA）的发病率在协和医院逐年增加。为了了解协和医院 MRSA 的分子进化，对 1994 年至 2008 年期间分离的 466 株非重复金黄色葡萄球菌进行了研究，包括 302 株 MRSA 和 164 株甲氧西林敏感金黄色葡萄球菌（MSSA），通过葡萄球菌盒染色体 mec（SCCmec）分型、spa 分型、脉冲场凝胶电泳（PFGE）和多位点序列分型（MLST）进行了特征分析。302 株 MRSA 分为 12 种 spa 型和 9 种序列型（ST）。1994 年至 2000 年期间，最主要的 MRSA 克隆是 ST239-MRSA-III-spa t037。自 2000 年以来，ST239-MRSA-III-spa t030 迅速取代 t037 并成为主要克隆。另一个克隆，ST5-MRSA-II-spa t002 于 2002 年出现，并一直以低流行率存在。164 株 MSSA 分为 62 种 spa 型和 40 种 ST。ST398 是 MSSA 最常见的 MLST 型，其次是 ST59、ST7、ST15 和 ST1。一些 MSSA 基因型，包括 ST398、ST1、ST121 和 ST59，与著名的社区获得性耐甲氧西林金黄色葡萄球菌（CA-MRSA）分离株相同。MLST eBURST 分析表明，ST5、ST59 和 ST965 克隆同时存在于 MRSA 和 MSSA 中，这表明这些 MRSA 克隆可能是通过获得 SCCmec 从 MSSA 进化而来的。根据临床资料，鉴定出两株携带 pvl 的 ST59-MRSA-IV 为 CA-MRSA。总的来说，我们的数据表明，ST239-MRSA-III-spa t037 克隆被新出现的 ST239-MRSA-III-spa t030 克隆所取代，这表明在中国一家三级医院 15 年来，MRSA 发生了快速变化。
