Humans may serve as a reservoir host of Staphylococcus aureus, resulting in transmission to animals. Previously, we used RNA polymerase beta subunit gene (rpoB)-based genotyping and classified S. aureus strains into rpoB sequence types (RSTs). According to our previous work, the predominant genotypes of S. aureus in humans and cows differ in Korea, but some predominant genotypes (RST4–1 and RST2–1) in humans have been isolated from bovine mastitis. Therefore, it needs to be determined whether some strains of the predominant human genotypes have adapted to or caused occasional infections in cows. We determined the whole genome sequences of 2 bovine mastitis-origin strains, PMB179 (RST4–1) and PMB196 (RST2–1), and performed comparative genomics with the corresponding RST4–1 and RST2–1 S. aureus strains in the NCBI database. We identified 257 and 180 pseudogenes among 131 RST4–1 and 54 RST2–1 strains, respectively, for the comparison of pseudogene profiles. RST4–1 strains shared more common pseudogenes than RST2–1 strains, and some epidemiologically related strains shared common pseudogenes. However, most of the pseudogenes were strain-specific, and diverse pseudogene profiles were apparent in both the RST4–1 and RST2–1 strains. Furthermore, analysis of the mobile genetic elements, virulence genes, and antibiotic resistance genes revealed no molecular markers to differentiate PMB179 and PMB196 from human strains. Interestingly, the collective comparison of RST4–1 or RST2–1 strains revealed cumulative acquisition steps of genomic islands and antibiotic resistance genes. In conclusion, our data support PMB179 and PMB196 causing occasional infections that result in bovine mastitis.

人类可能是金黄色葡萄球菌的宿主，导致向动物传播。以前，我们使用基于 RNA 聚合酶 β 亚基基因 ( rpoB ) 的基因分型并将金黄色葡萄球菌菌株分类为rpoB序列类型 (RST)。根据我们之前的工作，金黄色葡萄球菌的主要基因型在韩国，人类和奶牛的乳腺炎不同，但人类的一些主要基因型（RST4-1 和 RST2-1）已从牛乳腺炎中分离出来。因此，需要确定主要人类基因型的某些菌株是否已经适应或偶尔引起奶牛感染。我们确定了 2 种牛乳腺炎来源菌株 PMB179 (RST4-1) 和 PMB196 (RST2-1) 的全基因组序列，并与相应的 RST4-1 和 RST2-1金黄色葡萄球菌进行了比较基因组学 NCBI 数据库中的菌株。我们分别在 131 个 RST4-1 和 54 个 RST2-1 菌株中鉴定了 257 个和 180 个假基因，用于比较假基因谱。RST4-1 菌株比 RST2-1 菌株共享更多的常见假基因，并且一些与流行病学相关的菌株共享常见的假基因。然而，大多数假基因是菌株特异性的，并且在 RST4-1 和 RST2-1 菌株中都可以看到不同的假基因谱。此外，对可移动遗传元件、毒力基因和抗生素抗性基因的分析显示没有将 PMB179 和 PMB196 与人类菌株区分开来的分子标记。有趣的是，RST4-1 或 RST2-1 菌株的集体比较揭示了基因组岛和抗生素抗性基因的累积获取步骤。综上所述，