Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China.
Department of Clinical Laboratory, Ordos Central Hospital, Nei Mongol, China.
J Infect Dis. 2020 Mar 16;221(Suppl 2):S220-S228. doi: 10.1093/infdis/jiz575.
Sequence type (ST) 398 is the most prevalent clone of livestock-associated methicillin-resistant Staphylococcus aureus (MRSA). To evaluate the molecular characteristics and phylogeny of Chinese ST398 isolates, 4 MRSA ST398 strains and 4 methicillin-susceptible S. aureus (MSSA) ST398 strains were collected from patients with bacteremia at 6 teaching hospitals in China between 1999 and 2016. Moreover, 689 ST398 genome sequences were downloaded from the GenBank database for comparison. The 4 MRSA ST398 strains were resistant to β-lactam antibiotics, and 2 strains were also resistant to erythromycin. Among the 4 MSSA ST398 strains, 2 strains displayed multidrug resistance (MDR) and were resistant to penicillin, erythromycin, tetracycline, and gentamicin. The accessory genome of MSSA ST398 was more diverse than that of MRSA ST398. All 4 MRSA ST398 strains carried type V staphylococcal cassette chromosome mec elements; however, MSSA ST398 carried more resistance genes than MRSA ST398. These 4 MRSA ST398 strains carried hemolysin, along with virulence genes associated with immune invasion and protease. Phylogenic analysis showed that the 4 MRSA ST398 strains clustered in 1 clade. The global ST398 phylogeny showed that ST398 was divided into an animal clade and a human clade, and the ST398 strains of this study clustered in the human clade. A small number of human strains were also present in the animal clade and vice versa, suggesting transmission of ST398 between animals and humans. In conclusion, livestock-associated MRSA ST398 has caused severe infections in Chinese hospitals, and it should therefore be paid more attention to and monitored.
序列型 398 是最流行的与牲畜相关的耐甲氧西林金黄色葡萄球菌（MRSA）克隆。为了评估中国 ST398 分离株的分子特征和系统发育，我们从 1999 年至 2016 年期间在中国 6 所教学医院的血培养患者中收集了 4 株 MRSA ST398 株和 4 株甲氧西林敏感金黄色葡萄球菌（MSSA）ST398 株。此外，还从 GenBank 数据库中下载了 689 株 ST398 基因组序列进行比较。4 株 MRSA ST398 株对β-内酰胺类抗生素耐药，2 株还对红霉素耐药。在 4 株 MSSA ST398 株中，2 株表现出多重耐药（MDR），并对青霉素、红霉素、四环素和庆大霉素耐药。MSSA ST398 的辅助基因组比 MRSA ST398 更为多样化。所有 4 株 MRSA ST398 株均携带 V 型葡萄球菌盒式染色体 mec 元件；然而，MSSA ST398 携带的耐药基因比 MRSA ST398 多。这 4 株 MRSA ST398 株携带溶血性毒素，以及与免疫入侵和蛋白酶相关的毒力基因。系统发育分析表明，这 4 株 MRSA ST398 株聚集在 1 个分支中。全球 ST398 系统发育显示，ST398 分为动物分支和人类分支，本研究的 ST398 株聚集在人类分支中。少数人类菌株也存在于动物分支中，反之亦然，这表明 ST398 在动物和人类之间传播。总之，与牲畜相关的 MRSA ST398 已在中国医院引起严重感染，因此应引起更多关注和监测。
