Microbiology Division, Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia.
Diagn Microbiol Infect Dis. 2012 Oct;74(2):106-12. doi: 10.1016/j.diagmicrobio.2012.05.033. Epub 2012 Jul 6.
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main bacterial pathogens responsible for nosocomial infections leading to pneumonia, bloodstream, skin, and soft tissue infections. The objective of this study was to investigate the genomic changes of MRSA in a tertiary hospital between the years 2003, 2004, 2007, and 2008. One hundred fifty-four MRSA strains were characterized by multilocus sequence typing (MLST), spa, and mec-associated dru typing. Among the 154 strains, 29 different dru, 15 spa, and 8 MLST types were identified. Seven sequence types (STs) (ST239, ST22, ST5, ST6, ST80, ST573, and ST241) were identified among 2007-08 strains, although only 2 STs (ST239 and ST20) were observed among 2003 strains. Clones ST239-t037-dt13g, ST22-t032-(dt10a and dt10aw), and 28 other MRSA clones being introduced in 2007-2008 have replaced the ST239-t037 (dt13d, 14h, 13i, 13l, 13m, 15m, 15l, and 11al) clones present in 2003. The predominant MLST clone, ST239 (90.3%), was further distinguished into 7 different spa types and 26 different dru types, including 17 novel dru types. Maximum parsimony tree based on dru repeats revealed that 10 dru types (dt11am, dt13j, dt15n, dt13q, dt13n, dt13p, dt13f, dt13ao, dt12j, dt7v) shared the same MLST-spa types with dt13d, suggesting that these MRSA clones might have evolved from ST239-t037-dt13d. In conclusion, our data showed that the ST239-t037-dt13d clone and other MRSA clones in 2003 were replaced by ST239-t037-dt13g and other new emerging spa and dru types.
耐甲氧西林金黄色葡萄球菌（MRSA）是导致医院获得性肺炎、血流感染、皮肤和软组织感染的主要细菌病原体之一。本研究的目的是调查 2003 年、2004 年、2007 年和 2008 年三级医院中 MRSA 的基因组变化。对 154 株 MRSA 菌株进行多位点序列分型（MLST）、spa 和 mec 相关 dru 分型分析。在 154 株菌株中，鉴定出 29 种不同的 dru、15 种 spa 和 8 种 MLST 型。在 2007-08 年的菌株中发现了 7 种序列型（ST）（ST239、ST22、ST5、ST6、ST80、ST573 和 ST241），而在 2003 年的菌株中仅观察到 2 种 ST（ST239 和 ST20）。2007-2008 年引入的克隆 ST239-t037-dt13g、ST22-t032-（dt10a 和 dt10aw）和 28 个其他 MRSA 克隆已取代了 2003 年存在的 ST239-t037（dt13d、14h、13i、13l、13m、15m、15l 和 11al）克隆。主要的 MLST 克隆 ST239（90.3%）进一步分为 7 种不同的 spa 型和 26 种不同的 dru 型，包括 17 种新型 dru 型。基于 dru 重复的最大简约树显示，10 种 dru 型（dt11am、dt13j、dt15n、dt13q、dt13n、dt13p、dt13f、dt13ao、dt12j、dt7v）与 dt13d 具有相同的 MLST-spa 型，表明这些 MRSA 克隆可能是由 ST239-t037-dt13d 进化而来。总之，我们的数据表明，2003 年的 ST239-t037-dt13d 克隆和其他 MRSA 克隆已被 ST239-t037-dt13g 和其他新出现的 spa 和 dru 型取代。
