Structural comparison of three types of staphylococcal cassette chromosome mec integrated in the chromosome in methicillin-resistant Staphylococcus aureus
Structural comparison of three types of staphylococcal cassette chromosome mec integrated in the chromosome in methicillin-resistant Staphylococcus aureus
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DOI：
10.1128/aac.45.5.1323-1336.2001
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发表时间：
2001-05-01
影响因子：
4.9
通讯作者：
Hiramatsu, K
中科院分区：
文献类型：
--
作者：
Ito, T;Katayama, Y;Hiramatsu, K
金黄色葡萄球菌对β-内酰胺类抗生素耐药基因mecA由一种新的可移动遗传元件携带，命名为葡萄球菌盒式染色体mec(Sccmec)，该基因存在于耐甲氧西林的S金黄色葡萄球菌的染色体上。我们现在报告在世界其他国家分离的MRSA菌株中发现的另外两种携带mecA的遗传元件。这些元件在大小和核苷酸序列上与SCCmec有很大差异，但新元件与SCCmec具有相同的染色体整合位点。结构分析表明，它们具有SCCmec的所有显著特征：整合结合点保守的末端反向重复序列和直接重复序列，保守的mecA基因周围的遗传组织，以及负责SCCmec运动的盒式染色体重组酶(Ccr)基因的存在。因此，这些元件与先前已鉴定的SCCmec一起构成了SCCmec家族的葡萄球菌可移动遗传元件。34个在染色体上具有三个典型SCCmec元件之一。我们的发现表明，世界上至少有三个不同的MRSA克隆，它们的染色体上有不同类型的SCCmec。
The beta -lactam resistance gene mecA of Staphylococcus aureus is carried by a novel mobile genetic element, designated staphylococcal cassette chromosome mec (SCCmec), identified in the chromosome of a Japanese methicillin-resistant S, aureus (MRSA) strain. We now report identification of two additional types of mecA-carrying genetic elements found in the MRSA strains isolated in other countries of the world. There were substantial differences in the size and nucleotide sequences between the elements and the SCCmec, However, new elements shared the chromosomal integration site with the SCCmec, Structural analysis of the new elements revealed that they possessed all of the salient features of the SCCmec: conserved terminal inverted repeats and direct repeats at the integration junction points, conserved genetic organization around the mecA gene, and the presence of cassette chromosome recombinase (ccr) genes responsible for the movements of SCCmec, The elements, therefore, were considered to comprise the SCCmec family of staphylococcal mobile genetic elements together with the previously identified SCCmec, Among 38 epidemic MRSA strains isolated in 20 countries, 34 were shown to possess one of the three typical SCCmec elements on the chromosome. Our findings indicated that there are at least three distinct MRSA clones in the world with different types of SCCmec in their chromosome.