Beijing Key Laboratory of Detection Technology for Animal Food Safety, College of Veterinary Medicine, China Agricultural University, Beijing, China.
Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria 3004, Australia.
J Antimicrob Chemother. 2021 Jun 18;76(7):1703-1711. doi: 10.1093/jac/dkab106.
To reconstruct the evolutionary history and genomic epidemiology of Staphylococcus aureus ST9 in China.
Using WGS analysis, we described the phylogeny of 131 S. aureus ST9 isolates collected between 2002 and 2016 from 11 provinces in China, including six clinical samples from Taiwan. We also investigated the complex structure and distribution of the lsa(E)-carrying multiresistance gene cluster, and genotyped prophages in the genomes of the ST9 isolates.
ST9 was subdivided into one major (n = 122) and one minor (n = 9) clade. Bayesian phylogeny predicted the divergence of ST9 isolates in pig farming in China as early as 1987, which then evolved rapidly in the following three decades. ST9 isolates shared similar multiresistance properties, which were likely acquired before the ST9 emergence in China. The accessory genome is highly conserved, and ST9 harboured similar sets of phages, but lacked certain virulence genes.
Host exchange and regional transmission of ST9 have occurred between pigs and humans. Pig rearing and trading might have favoured gene exchanges between ST9 isolates. Resistance genes, obtained from the environment and other isolates, were stably integrated into the chromosomal DNA. The abundance of resistance genes among ST9 is likely attributed to the extensive use of antimicrobial agents in livestock. Phages are present in the genomes of ST9 and may play a role in the rapid evolution of this ST. Although human ST9 infections are rare, ST9 isolates may constitute a potential risk to public health as a repository of antimicrobial resistance genes.
重建中国金黄色葡萄球菌 ST9 的进化历史和基因组流行病学。
通过 WGS 分析，我们描述了 2002 年至 2016 年间从中国 11 个省份（包括来自台湾的 6 个临床样本）采集的 131 株金黄色葡萄球菌 ST9 分离株的系统发育。我们还研究了携带 lsa(E)-carrying 多耐药基因簇的复杂结构和分布，以及 ST9 分离株基因组中的噬菌体基因型。
ST9 分为一大（n=122）一小（n=9）两个分支。贝叶斯系统发育预测，中国养猪场的 ST9 分离株早在 1987 年就已经发生了分化，随后在接下来的三十年中迅速进化。ST9 分离株具有相似的多耐药特性，这些特性可能是在 ST9 在中国出现之前获得的。辅助基因组高度保守，ST9 携带相似的噬菌体集，但缺乏某些毒力基因。
ST9 在猪与人之间发生了宿主交换和区域性传播。猪的养殖和贸易可能促进了 ST9 分离株之间的基因交换。来自环境和其他分离株的耐药基因被稳定地整合到染色体 DNA 中。ST9 中大量存在的耐药基因可能归因于在畜牧业中广泛使用抗菌药物。噬菌体存在于 ST9 的基因组中，可能在该 ST 的快速进化中发挥作用。虽然人类 ST9 感染很少见，但 ST9 分离株可能因其携带的抗生素耐药基因而对公共卫生构成潜在威胁。
