Wu Zhaowei, Li Fan, Liu Dongliang, Xue Huping, Zhao Xin
College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, People's Republic of China.
College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
Antimicrob Agents Chemother. 2015 Dec;59(12):7597-601. doi: 10.1128/AAC.01692-15. Epub 2015 Sep 28.
Excision and integration of staphylococcal cassette chromosome mec (SCCmec) are mediated by cassette chromosome recombinases (Ccr), which play a crucial role in the worldwide spread of methicillin resistance in staphylococci. We report a novel ccr gene, ccrC2, in the SCCmec of a Staphylococcus aureus isolate, BA01611, which showed 62.6% to 69.4% sequence identities to all published ccrC1 sequences. A further survey found that the ccrC2 gene was mainly located among coagulase-negative staphylococci (CoNS) and could be found in staphylococcal isolates from China, the United States, France, and Germany. The ccr gene complex harboring the ccrC2 gene was designated a type 9 complex, and the SCCmec of BA01611 was considered a novel type and was designated type XII (9C2). This novel SCCmec element in BA01611 was flanked by a pseudo-SCC element (ΨSCCBA01611) carrying a truncated ccrA1 gene. Both individual SCC elements and a composite SCC were excised from the chromosome based on detection of extrachromosomal circular intermediates. We advocate inclusion of the ccrC2 gene and type 9 ccr gene complex during revision of the SCCmec typing method.
葡萄球菌盒式染色体mec（SCCmec）的切除和整合由盒式染色体重组酶（Ccr）介导，其在葡萄球菌中甲氧西林耐药性的全球传播中起关键作用。我们在一株金黄色葡萄球菌分离株BA01611的SCCmec中报道了一个新的ccr基因ccrC2，它与所有已发表的ccrC1序列的序列同一性为62.6%至69.4%。进一步调查发现，ccrC2基因主要位于凝固酶阴性葡萄球菌（CoNS）中，并且可以在来自中国、美国、法国和德国的葡萄球菌分离株中发现。携带ccrC2基因的ccr基因复合体被指定为9型复合体，BA01611的SCCmec被认为是一种新型，被指定为XII型（9C2）。BA01611中的这种新型SCCmec元件侧翼是一个携带截短的ccrA1基因的假SCC元件（ΨSCCBA01611）。基于染色体外环状中间体的检测，单个SCC元件和复合SCC均从染色体上切除。我们主张在修订SCCmec分型方法时纳入ccrC2基因和9型ccr基因复合体。
