Staphylococcal Cassette Chromosome mec-Like Element in Macrococcus caseolyticus
Staphylococcal Cassette Chromosome mec-Like Element in Macrococcus caseolyticus
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DOI：
10.1128/aac.00575-09
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发表时间：
2010-04-01
影响因子：
4.9
通讯作者：
Hiramatsu, Keiichi
中科院分区：
文献类型：
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作者：
Tsubakishita, Sae;Kuwahara-Arai, Kyoko;Hiramatsu, Keiichi
巨球菌属是与葡萄球菌属密切相关的细菌属，葡萄球菌属通常从动物皮肤和产品中分离。先前对从鸡中分离的多重耐药溶酪巨球菌菌株JCSC 5402进行的基因组分析鉴定出了质粒pMCCL 2，该质粒携带一个转座子，该转座子含有一种不寻常形式的巨球菌mec基因复合物（mecA（m）-mecR 1（m）-mecI（m）-blaZ（m））。In M.在溶酪蛋白芽孢杆菌菌株JCSC 7096中，发现这种含有mec基因复合物的mec转座子（在本研究中命名为Tn 6045）整合在染色体上orfX的下游。JCSC 7096的Tn 6045被盒式染色体重组酶（CCR）特异性识别的直接重复序列（DR）包围。将一个不含mecA的葡萄球菌盒式染色体（SCC）元件（SCC 7096）整合到mec转座子旁边，并通过DR将其与mec转座子分离。巢式PCR实验表明，mec转座子不仅被单独切除，而且还与SCC 7096从染色体的DR处共切除，共切除的元件形成SCCmec样元件的染色体外闭合环状DNA。已知SCCmec是葡萄球菌中传递甲氧西林（甲氧西林）耐药性的移动的元件。然而，它的起源一直不明。我们的观察揭示了一个潜在的机制，产生一个新的SCCmec样元件在M。溶酪菌，一种食用动物的肠道细菌。
Macrococcus is a bacterial genus that is closely related to Staphylococcus, which typically is isolated from animal skin and products. The genome analysis of multidrug-resistant Macrococcus caseolyticus strain JCSC5402, isolated from chicken, previously led to the identification of plasmid pMCCL2, which carries a transposon containing an unusual form of the Macrococcus mec gene complex (mecA(m)-mecR1(m)-mecI(m)-blaZ(m)). In M. caseolyticus strain JCSC7096, this mec transposon containing the mec gene complex ( designated Tn6045 in this study) was found integrated downstream of orfX on the chromosome. Tn6045 of JCSC7096 was bracketed by the direct repeat sequences (DR) specifically recognized by cassette chromosome recombinase (CCR). A non-mecA-containing staphylococcal cassette chromosome (SCC) element, designated SCC7096, was integrated next to the mec transposon and separated from the latter by a DR. Nested PCR experiments showed that the mec transposon not only was excised singly but also coexcised with SCC7096 from the chromosome at the DRs. The coexcised elements formed the extrachromosomal closed circular DNA of the SCCmec-like element. SCCmec is known to be the mobile element conveying methicillin (meticillin) resistance in staphylococci. However, its origin has been unknown. Our observation revealed a potential mechanism of the generation of a new SCCmec-like element in M. caseolyticus, a commensal bacterium of food animals.