Community-acquired methicillin-resistant Staphylococcus aureus from ST 1 lineage harboring a new SCCmec IV subtype (SCCmec IVm) containing the tetK gene
Community-acquired methicillin-resistant Staphylococcus aureus from ST 1 lineage harboring a new SCCmec IV subtype (SCCmec IVm) containing the tetK gene
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DOI：
10.2147/idr.s175079
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发表时间：
2018-01-01
影响因子：
3.9
通讯作者：
Figueiredo, Agnes M. S.
中科院分区：
文献类型：
--
作者：
Cortes, Marina F.;Botelho, Ana M. N.;Figueiredo, Agnes M. S.
耐甲氧西林金黄色葡萄球菌 (MRSA) 进化路径中的一个关键事件是获得携带 mecA 基因的葡萄球菌盒式染色体 mec (SCCmec) 元件，mecA 基因是甲氧西林耐药性的决定因素。社区获得性 (CA) MRSA 通常与皮肤/软组织感染有关，强力霉素是用于此目的的药物选择之一。多西环素耐药性与金黄色葡萄球菌质粒 pT181 携带的 tetK 基因的获得有关，该基因也可能整合到 SCCmec III 和 V 中。本研究的目的是描述携带 tetK 的新型 SCCmec IV 亚型 (IVm) 并揭示该元件的遗传背景。 SCCmec 序列是通过 MRSA 菌株 2288 (ST1 CA-MRSA) 的全基因组测序和使用不同生物信息学工具进行的基因组分析获得的。发现pT181的拷贝被整合到菌株2288的新SCOmec IVm中。SCCmec IVm与菌株MW2的SCCmec IVa具有高核苷酸同一性(99%)，除了J3区域之外，其中插入了携带tetK基因的pT181。在该区域发现了 pT181 侧翼的反向重复序列 (IR)，表明发生了重组事件。 2288 菌株（spa t125 型）与 MW2（spa t128 型）具有大部分毒力属性，MW2 过去被认为是美国儿童严重感染的原因。系统发育树中的分支模式描绘了2228菌株和来自美国的其他MRSA（包括ERS410852、TCH70、CIG1835、CO-41、MW2和USA400-0051）共享的最近共同祖先，但它们都不携带pT181。这项研究还表明，SCCmec IVm 携带的 tetK 具有功能性，决定了对多西环素和四环素的耐药性。通过获得这种新的 SCCmec 亚型，tetK 和 mecA 基因在同一遗传事件中的潜在传播引起了社区感染的关注。
A pivotal event in the evolutionary path of methicillin-resistant Staphylococcus vas auleus (MRSA) is the acquisition of the staphylococcal cassette chromosome mec (SCCmec) element carrying the mecA gene, the determinant of methicillin resistance. Community-acquired (CA) MRSA is commonly associated with skin/soft tissue infections, and doxycycline is one of the drug choices for this purpose. Doxycycline resistance is associated with the acquisition of the tetK gene carried by the S. aureus plasmid pT181, which may also be integrated into SCCmec III and V. The aim of this study was to describe a novel SCCmec IV subtype (IVm) carrying tetK and reveal the genetic context of this element. The SCCmec sequence was obtained by whole-genome sequencing of the MRSA strain 2288 (ST1 CA-MRSA) and genomic analysis performed using different bioinformatics tools. A copy of pT181 was found to be integrated in the new SCOmec IVm of the strain 2288. The SCCmec IVm has high nucleotide identity (99%) with SCCmec IVa of the strain MW2, except for the J3 region, where the pT181- carrying tetK gene - is inserted. Inverted repeats (IRs) flanking pT181 were found in this region, suggesting the occurrence of recombination events. The strain 2288 (spa type t125) shares most of the virulence attributes with MW2 (spa type t128), which is recognized in the past as a cause of severe infections in children in USA. The pattern of branching in the phylogenetic tree depicts a recent common ancestor shared by the 2228 strain and other MRSA from USA, including ERS410852, TCH70, CIG1835, CO-41, MW2, and USA400-0051, but none of them carried pT181. This study also showed that the tetK carried by SCCmec IVm is functional, determining resistance to doxycycline and tetracycline. The potential dissemination of the tetK and mecA genes in the same genetic event by the acquisition of this new SCCmec subtype is of concern for community infections.