Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
J Antimicrob Chemother. 2020 Nov 1;75(11):3131-3134. doi: 10.1093/jac/dkaa313.
USA300 [ST8-staphylococcal cassette chromosome mec type IVa (ST8-IVa)/arginine catabolic mobile element (ACME) positive] is a major Panton-Valentine leucocidin (PVL)-positive community-acquired MRSA (CA-MRSA) clone. In Japan, we identified USA300-like strains with characteristics (ST8-IVc/ACME negative) similar to those of USA300.
To reveal the evolution of the USA300-like strains.
The whole-genome sequence of a USA300-like strain was determined and genome analysis was performed using Type Strain Genome Server, MUSCLE and progressiveMauve.
Genome-based phylogenetic analysis showed that the USA300-like strain is more similar to the USA300-Latin American variant (USA300-LV), which is a PVL-positive CA-MRSA clone identified in South America, than to USA300. Instead of the ACME, copper and mercury resistance mobile elements were located on the genome of the USA300-like strain. In addition, the USA300-like strain possessed a unique mobile genetic element, ICE6013. Therefore, we named this novel USA300-LV variant identified in Japan as USA300-LV/J.
Our findings strongly suggest that a PVL-positive CA-MRSA USA300-LV/J clone originating from abroad has uniquely evolved and disseminated in Japan.
USA300[ST8-葡萄球菌盒式染色体 mec 型 IVa（ST8-IVa）/精氨酸分解移动元件（ACME）阳性]是一种主要的潘顿-瓦伦丁白细胞毒素（PVL）阳性社区获得性耐甲氧西林金黄色葡萄球菌（CA-MRSA）克隆。在日本，我们发现了具有与 USA300 相似特征（ST8-IVc/ACME 阴性）的 USA300 样菌株。
揭示 USA300 样菌株的进化情况。
测定了一株 USA300 样菌株的全基因组序列，并使用 Type Strain Genome Server、MUSCLE 和 progressiveMauve 进行了基因组分析。
基于基因组的系统发育分析表明，与 USA300 相比，USA300 样菌株与在南美洲发现的 PVL 阳性 CA-MRSA 克隆 USA300-拉丁美洲变体（USA300-LV）更为相似。ACME 被铜和汞耐药移动元件取代，位于 USA300 样菌株的基因组上。此外，USA300 样菌株还具有独特的移动遗传元件 ICE6013。因此，我们将在日本发现的这种新型 USA300-LV 变体命名为 USA300-LV/J。
我们的研究结果强烈表明，源自国外的具有 PVL 阳性的 CA-MRSA USA300-LV/J 克隆在日本独特地进化和传播。
