Genetic background affects stability of mecA in Staphylococcus aureus.
Genetic background affects stability of mecA in Staphylococcus aureus.
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遗传背景影响金黄色葡萄球菌中 mecA 的稳定性。
DOI：
10.1128/jcm.43.5.2380-2383.2005
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发表时间：
2005
影响因子：
9.4
通讯作者：
Chambers,HenryF
中科院分区：
文献类型：
--
作者：
Katayama,Yuki;Robinson,DAshley;Enright,MarkC;Chambers,HenryF
葡萄球菌甲氧西林耐药决定簇mecA存在于移动的遗传元件--染色体盒mec（SCCmec）上。SCCmecin的分布局限于相对较少的耐甲氧西林金黄色葡萄球菌（MRSA）的克隆复合物。我们之前曾报道过，一些遗传背景限制了mecA和青霉素结合蛋白2a的表达，这可能是SCCmecin本质上克隆分布受限的原因。在这项研究中，我们研究了宿主染色体在103个天然存在的甲氧西林耐药菌株中的转化能力和mecA表达中的潜在作用。金黄色葡萄球菌根据分离株是否属于“主要”MRSA谱系或从未或偶尔为MRSA的“其他”谱系，将先前已通过多位点序列分型进行基因分型的分离株分为两个相互排斥的类别之一。我们将表达在低拷贝质粒pYK 20上的mecA导入每株MSSA中，通过群体分析来检测耐药表型，以评估mecA表达的稳定性与遗传背景的关系。与来自其他谱系的菌株相比，来自主要MRSA谱系的菌株更易被pYK 20转化，并且能够更好地维持质粒并表达抗性。这些数据支持这样的假设，即在相对较少的克隆复合体中存在的mecA部分是由于允许mecA及其基因产物的遗传因素。
The staphylococcal methicillin resistance determinant,mecA, resides on a mobile genetic element, staphylococcus chromosomal cassettemec(SCCmec). The distribution of SCCmecin nature is limited to relatively few clonal complexes of related methicillin-resistantStaphylococcus aureus(MRSA). We have previously reported that some genetic backgrounds are restrictive ofmecAand penicillin-binding protein 2a expression, which could account for the restricted clonal distribution of SCCmecin nature. In this study, we investigate the potential role of the host chromosome in the transformability and expression ofmecAin 103 naturally occurring methicillin-susceptibleS. aureusclinical isolates. The isolates, which had been genotyped previously by multilocus sequence typing, were classified into one of two mutually exclusive categories based on whether the isolates belonged to “major” MRSA lineages or to “other” lineages that are never or occasionally MRSA. We introducedmecAexpressed on the low-copy-number plasmid pYK20 into each MSSA strain and assayed the phenotype of resistance to nafcillin by population analysis to assess the relationship between the stability ofmecAexpression and genetic background. Strains from the major MRSA lineages were more transformable with pYK20 and better able to maintain the plasmid and express resistance in comparison to strains from other lineages. These data support the hypothesis that the presence ofmecAwithin relatively few clonal complexes is partly due to genetic factors that are permissive ofmecAand its gene product.