Ibrahem S, Salmenlinna S, Lyytikäinen O, Vaara M, Vuopio-Varkila J
Department of Bacterial and Inflammatory Diseases, National Public Health Institute, Helsinki, Finland.
Clin Microbiol Infect. 2008 Nov;14(11):1020-7. doi: 10.1111/j.1469-0691.2008.02080.x.
In order to study the clonality of clinical methicillin-resistant Staphylococcus epidermidis (MRSE) strains and their staphylococcal cassette chromosome mec (SCCmec) elements, 60 isolates of MRSE from bacteraemic patients in three units of the Helsinki University Hospital, Finland were selected, covering the periods 1990-1993 and 1997-1998. The MRSE strains were analysed by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing and SCCmec typing. Eleven PFGE types (FIN-SE-1-11) with sequence type ST2 (clonal complex 2; CC2) were identified. The previously established methicillin-resistant Staphylococcus aureus SCCmec criteria were applied to name the MRSE SCCmec complexes, and it was found that 7% of the isolates carried SCCmec type IA (ccrA1, class B), whereas the majority (93%) yielded six non-typeable SCCmec PCR patterns (P1-P6). Within each SCCmec PCR pattern, two ccr recombinase genes (ccrA2 and ccrA3) and two mec gene complexes (class A and class B) were detected. In addition, the ccrC gene was associated with three of the six patterns. In conclusion, the MRSE strains were genetically related to each other (ST2) but their SCCmec complexes were unique combinations of elements previously recognized among SCCmec types III and IV.
为研究临床耐甲氧西林表皮葡萄球菌（MRSE）菌株及其葡萄球菌盒式染色体mec（SCCmec）元件的克隆性，选取了芬兰赫尔辛基大学医院三个科室1990 - 1993年及1997 - 1998年期间菌血症患者的60株MRSE分离株。通过脉冲场凝胶电泳（PFGE）、多位点序列分型和SCCmec分型对MRSE菌株进行分析。鉴定出11种PFGE型（FIN - SE - 1 - 11），序列型为ST2（克隆复合体2；CC2）。应用先前建立的耐甲氧西林金黄色葡萄球菌SCCmec标准来命名MRSE的SCCmec复合体，发现7%的分离株携带IA型SCCmec（ccrA1，B类），而大多数（93%）产生六种不可分型的SCCmec PCR模式（P1 - P6）。在每种SCCmec PCR模式中，检测到两个ccr重组酶基因（ccrA2和ccrA3）和两个mec基因复合体（A类和B类）。此外，ccrC基因与六种模式中的三种相关。总之，MRSE菌株彼此之间存在遗传关联（ST2），但其SCCmec复合体是先前在III型和IV型SCCmec中识别的元件的独特组合。
