Whole-Genome Analysis of Livestock-Associated Methicillin-Resistant Staphylococcus aureus Sequence Type 398 Strains Isolated From Patients With Bacteremia in China
Whole-Genome Analysis of Livestock-Associated Methicillin-Resistant Staphylococcus aureus Sequence Type 398 Strains Isolated From Patients With Bacteremia in China
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DOI：
10.1093/infdis/jiz575
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发表时间：
2020-04-01
影响因子：
6.4
通讯作者：
Wang, Hui
中科院分区：
文献类型：
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作者：
Chen, Hongbin;Yin, Yuyao;Wang, Hui
序列类型(ST)398是家畜耐甲氧西林金黄色葡萄球菌(MRSA)最常见的克隆。为探讨我国分离的ST398菌株的分子特征和系统发育关系，收集1999年至2016年中国6所教学医院菌血症患者分离的4株耐甲氧西林金黄色葡萄球菌和4株甲氧西林敏感的金黄色葡萄球菌。此外，还从GenBank数据库下载了689个ST398基因组序列进行比对。4株MRSA ST398对β-内酰胺类抗生素耐药，2株对红霉素耐药。4株MSSA ST398菌株中，2株对青霉素、红霉素、四环素、庆大霉素耐药。MSSA ST398的辅助基因组比MRSA ST398更具多样性。4株MRSA ST398均携带V型葡萄球菌盒染色体mec元件，但MSSA ST398携带的耐药基因多于MRSA ST398。这4株MRSA ST398菌株携带溶血素，以及与免疫侵袭和蛋白酶相关的毒力基因。系统发育分析表明，4株MRSA ST398菌株聚为1个分支。ST398的全球系统发育树表明，ST398分为一个动物分支和一个人类分支，本研究的ST398菌株聚在人类分支。在动物分支中也存在少量的人类菌株，反之亦然，这表明ST398在动物和人类之间传播。综上所述，家畜相关的MRSA ST398已在中国医院引起严重感染，因此应该引起更多的关注和监测。
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 beta-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.