Gene acquisition at the insertion site for SCCmec, the genomic island conferring methicillin resistance in Staphylococcus aureus
Gene acquisition at the insertion site for SCCmec, the genomic island conferring methicillin resistance in Staphylococcus aureus
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DOI：
10.1128/jb.01128-07
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发表时间：
2008-02-01
影响因子：
3.2
通讯作者：
Archer, Gordon L.
中科院分区：
文献类型：
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作者：
Noto, Michael J.;Kreiswirth, Barry N.;Archer, Gordon L.
金黄色葡萄球菌通过获得一个基因组岛（称为葡萄球菌染色体盒mec（SCCmec））而对甲氧西林产生耐药性，该基因组岛含有甲氧西林耐药决定簇mecA。SCCmec是位点特异性整合到葡萄球菌染色体上的一个位点，称为SCCmec附着位点（attB）。为了更好地了解甲氧西林敏感的S。金黄色葡萄球菌（MSSA）分离株获得SCCmec的方法，在42个MSSA分离株的不同集合中检查attB和周围DNA区域的核苷酸序列。attB周围的染色体区域在所研究的分离株之间变化，并且似乎是获得性外源DNA的常见插入点。插入高达15.1 kb，发现含有开放的阅读框与肠毒素基因，限制修饰系统，转座酶，和一些序列，以前没有在葡萄球菌中描述的同源性。两组，包含8个和4个分离株，在已知的SCCmec元件中发现的序列，表明SCCmec元件可能是通过在该位点重复插入DNA而进化的。此外，该集合中的大多数MSSA分离株的attB序列与已证明整合酶介导的SCCmec插入或切除的菌株的attB序列不同，这表明一些S.金黄色葡萄球菌分离株可能缺乏将SCCmec位点特异性整合到其染色体中的能力。
Staphylococcus aureus becomes resistant to methicillin by acquiring a genomic island, known as staphylococcal chromosome cassette mec (SCCmec), which contains the methicillin resistance determinant, mecA. SCCmec is site-specifically integrated into the staphylococcal chromosome at a locus known as the SCCmec attachment site (attB). In an effort to gain a better understanding of the potential that methicillin-sensitive S. aureus (MSSA) isolates have for acquiring SCCmec, the nucleotide sequences of attB and surrounding DNA regions were examined in a diverse collection of 42 MSSA isolates. The chromosomal region surrounding attB varied among the isolates studied and appears to be a common insertion point for acquired foreign DNA. Insertions of up to 15.1 kb were found containing open reading frames with homology to enterotoxin genes, restriction-modification systems, transposases, and several sequences that have not been previously described in staphylococci. Two groups, containing eight and four isolates, had sequences found in known SCCmec elements, suggesting SCCmec elements may have evolved through repeated DNA insertions at this locus. In addition, the attB sequences of the majority of MSSA isolates in this collection differ from the attB sequences of strains for which integrase-mediated SCCmec insertion or excision has been demonstrated, suggesting that some S. aureus isolates may lack the ability to site-specifically integrate SCCmec into their chromosomes.