Laplana Leticia Millán, Cepero M A Pilar Goñi, Ruiz Joaquim, Zolezzi Paula Cerdá, Calvo M A Carmen Rubio, Erazo Melisa Canales, Gómez-Lus Rafael
Department of Microbiology, Preventive Medicine and Public Health, Faculty of Medicine, University of Zaragoza, C/Domingo Miral s/n, 50009 Zaragoza, Spain.
Int J Antimicrob Agents. 2007 Dec;30(6):505-13. doi: 10.1016/j.ijantimicag.2007.06.020. Epub 2007 Sep 14.
Pulsed-field gel electrophoresis (PFGE) of SmaI macrorestriction fragments of genomic DNA as well as staphylococcal cassette chromosome mec (SCCmec) typing for mecA-carrying isolates were used to study the distribution of clonal types among 177 Staphylococcus aureus clinical isolates recovered in a Spanish hospital between 2000 and 2003. Five major clonal types (P1 to P5) were identified by PFGE, with one of them (P1) comprising the majority of strains (47.5%). According to SCCmec typing, SCCmec type IVA was the most prevalent type, showing increasing prevalence in the hospital setting with respect to other pandemic clones. One SCCmec pattern was detected in different PFGE types, which demonstrates that the latter is a major discriminative typing method. Three novel SCCmec elements or variants were found, each in a different PFGE type. Oxacillin (methicillin)-resistant and -susceptible S. aureus (MRSA and MSSA, respectively) strains were detected showing identical PFGE patterns, suggesting horizontal transfer of mecA to MSSA and/or mecA deletion from MRSA. Persistence of several S. aureus clones throughout the years within the same hospital environment was also observed.
对基因组DNA的SmaI酶切大片段进行脉冲场凝胶电泳（PFGE），并对携带mecA基因的分离株进行葡萄球菌盒式染色体mec（SCCmec）分型，以研究2000年至2003年期间在一家西班牙医院分离出的177株金黄色葡萄球菌临床分离株中克隆型的分布情况。通过PFGE鉴定出五种主要克隆型（P1至P5），其中一种（P1）包含大多数菌株（47.5%）。根据SCCmec分型，IVA型SCCmec是最常见的类型，在医院环境中的流行率相对于其他大流行克隆呈上升趋势。在不同的PFGE类型中检测到一种SCCmec模式，这表明PFGE是一种主要的鉴别分型方法。发现了三种新的SCCmec元件或变体，每种都存在于不同的PFGE类型中。检测到耐苯唑西林（耐甲氧西林）和对苯唑西林敏感的金黄色葡萄球菌（分别为MRSA和MSSA）菌株具有相同的PFGE模式，这表明mecA基因可水平转移至MSSA和/或从MRSA中缺失。还观察到在同一家医院环境中，多年来几种金黄色葡萄球菌克隆持续存在。
