背景:金黄色葡萄球菌可以感染并适应多种宿主物种。然而,我们对其通才生活方式的遗传和进化驱动因素的理解仍然不足。当考虑金黄色葡萄球菌的当地人群时,这一点尤其重要,细菌谱系之间和宿主物种之间的紧密物理接近可能促进它们之间的频繁和重复相互作用。这里,我们旨在阐明从美国东北部地区的疾病病例中取样的437个分离株中的人和动物来源的金黄色葡萄球菌之间的基因组差异.
结果:多位点序列分型显示存在75种先前识别的序列类型(ST)。我们的群体基因组分析揭示了三个显性金黄色葡萄球菌谱系(ST5,ST8,ST30)的辅助基因组含量的异质性。抗菌素耐药性相关基因,毒力,根据宿主(人与非人)和三种主要的STs,质粒类型在分离株之间差异分布。在整个人口中,我们共发现1,912个重组事件发生在765个基因中.同源重组的频率和影响在人和动物来源的分离株之间是相当的。低频ST是重组DNA的主要供体,不管他们的主人的身份。最常见的重组基因(clfB,aroA,sraP)在宿主感染和毒力中的功能,它们也经常在稀有血统之间共享。
结论:综合来看,这些结果表明,在共同循环的金黄色葡萄球菌谱系之间频繁但可变的重组模式,包括低频谱系,穿越宿主障碍塑造了局部基因库的结构和宿主相关遗传变异的库。我们的研究为遗传和进化因素提供了重要的见解,这些因素有助于金黄色葡萄球菌在多种宿主物种中定植和引起疾病的能力。我们的研究强调了连续监测在不同生态宿主生态位中循环的金黄色葡萄球菌的重要性,以及对其进行系统采样的必要性。这些发现将为开发控制金黄色葡萄球菌定植的有效措施提供信息。感染,以及在一个健康连续体中的传播。
Staphylococcus aureus can infect and adapt to multiple host species. However, our understanding of the genetic and evolutionary drivers of its generalist lifestyle remains inadequate. This is particularly important when considering local populations of S. aureus, where close physical proximity between bacterial lineages and between host species may facilitate frequent and repeated interactions between them. Here, we aim to elucidate the genomic differences between human- and animal-derived S. aureus from 437 isolates sampled from disease cases in the northeast region of the United States.
Multi-locus sequence typing revealed the existence of 75 previously recognized sequence types (ST). Our population genomic analyses revealed heterogeneity in the accessory genome content of three dominant S. aureus lineages (ST5, ST8, ST30). Genes related to antimicrobial resistance, virulence, and plasmid types were differentially distributed among isolates according to host (human versus non-human) and among the three major STs. Across the entire population, we identified a total of 1,912 recombination events that occurred in 765 genes. The frequency and impact of homologous recombination were comparable between human- and animal-derived isolates. Low-frequency STs were major donors of recombined DNA, regardless of the identity of their host. The most frequently recombined genes (clfB, aroA, sraP) function in host infection and virulence, which were also frequently shared between the rare lineages.
Taken together, these results show that frequent but variable patterns of recombination among co-circulating S. aureus lineages, including the low-frequency lineages, that traverse host barriers shape the structure of local gene pool and the reservoir of host-associated genetic variants. Our study provides important insights to the genetic and evolutionary factors that contribute to the ability of S. aureus to colonize and cause disease in multiple host species. Our study highlights the importance of continuous surveillance of S. aureus circulating in different ecological host niches and the need to systematically sample from them. These findings will inform development of effective measures to control S. aureus colonization, infection, and transmission across the One Health continuum.