Åvall-Jääskeläinen Silja, Taponen Suvi, Kant Ravi, Paulin Lars, Blom Jochen, Palva Airi, Koort Joanna
Department of Veterinary Biosciences, Division of Microbiology and Epidemiology, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
PeerJ. 2018 Mar 30;6:e4560. doi: 10.7717/peerj.4560. eCollection 2018.
Non-aureus staphylococci (NAS) are most commonly isolated from subclinical mastitis. Different NAS species may, however, have diverse effects on the inflammatory response in the udder. We determined the genome sequences of 20 staphylococcal isolates from clinical or subclinical bovine mastitis, belonging to the NAS species and , and focused on the putative virulence factor genes present in the genomes. For comparison we used our previously published genome sequences of four isolates from bovine mastitis. The pan-genome and core genomes of the non-aureus isolates were characterized. After that, putative virulence factor orthologues were searched . We compared the presence of putative virulence factors in the NAS species and and evaluated the potential association between bacterial genotype and type of mastitis (clinical vs. subclinical). The NAS isolates had much less virulence gene orthologues than the isolates. One third of the virulence genes were detected only in . About 100 virulence genes were present in all isolates, compared to about 40 to 50 in each NAS isolate. differed the most. Several of the virulence genes detected among NAS were harbored only by , but it also lacked a number of genes present both in and . The type of mastitis was not associated with any specific virulence gene profile. It seems that the virulence gene profiles or cumulative number of different virulence genes are not directly associated with the type of mastitis (clinical or subclinical), indicating that host derived factors such as the immune status play a pivotal role in the manifestation of mastitis.
非金黄色葡萄球菌（NAS）最常从亚临床型乳腺炎中分离得到。然而，不同的NAS菌种可能对乳腺中的炎症反应有不同影响。我们测定了20株来自临床或亚临床型牛乳腺炎的葡萄球菌分离株的基因组序列，这些分离株属于NAS菌种 和 ，并重点关注基因组中存在的假定毒力因子基因。为了进行比较，我们使用了之前发表的4株来自牛乳腺炎的 分离株的基因组序列。对非金黄色葡萄球菌分离株的泛基因组和核心基因组进行了表征。之后，搜索假定的毒力因子直系同源物。我们比较了NAS菌种 和 中假定毒力因子的存在情况，并评估了细菌基因型与乳腺炎类型（临床型与亚临床型）之间的潜在关联。NAS分离株的毒力基因直系同源物比 分离株少得多。三分之一的毒力基因仅在 中检测到。所有 分离株中存在约100个毒力基因，相比之下，每个NAS分离株中约有40至50个。 差异最大。在NAS中检测到的几种毒力基因仅由 携带，但它也缺少 和 中都存在的一些基因。乳腺炎的类型与任何特定的毒力基因谱均无关联。似乎毒力基因谱或不同毒力基因的累积数量与乳腺炎类型（临床型或亚临床型）没有直接关联，这表明宿主来源的因素如免疫状态在乳腺炎的表现中起关键作用。
