Xu Wanyou, Lu Qiangsheng, Tian Meijuan, Yuan Lvfeng, Song Yangming, Zeng Qiaoying, Peng Jie
College of Veterinary Medicine, Gansu Agricultural University, Gansu, China.
Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.
Vet Res. 2025 Jul 3;56(1):135. doi: 10.1186/s13567-025-01567-z.
Streptococcus agalactiae (S. agalactiae), also known as Group B Streptococcus (GBS), is an important zoonotic pathogen. It is an important pathogen that causes bovine mastitis and can also lead to severe infections in newborns, pregnant women, and individuals with a weakened immune system. Adhesion to host cells is the first critical step in S. agalactiae infection, making the identification of key adhesion-related genes essential for understanding the pathogenic mechanisms of GBS. In this study, we used the Tn transposon system to construct a mutant library of S. agalactiae A909 and employed the mouse mammary epithelial cell line EPH4-Ev as a model to screen and validate adhesion-related genes. Our results revealed a gene cluster containing BP, AP1, and SrtC. While these genes did not affect the basic biological characteristics of the bacteria, they significantly influenced the adhesion rate to cells and the virulence of A909 in mice. Further transcriptomic analysis revealed that the Tnfsf15 gene plays a critical role in the regulation of A909 strain pathogenicity mediated by the BP, AP1, and SrtC gene clusters during host infection.
无乳链球菌（S. agalactiae），也称为B族链球菌（GBS），是一种重要的人畜共患病原体。它是引起牛乳腺炎的重要病原体，还可导致新生儿、孕妇和免疫系统较弱的个体发生严重感染。粘附于宿主细胞是无乳链球菌感染的第一个关键步骤，因此鉴定关键的粘附相关基因对于理解GBS的致病机制至关重要。在本研究中，我们使用Tn转座子系统构建了无乳链球菌A909的突变体文库，并采用小鼠乳腺上皮细胞系EPH4-Ev作为模型来筛选和验证粘附相关基因。我们的结果揭示了一个包含BP、AP1和SrtC的基因簇。虽然这些基因不影响细菌的基本生物学特性，但它们显著影响对细胞的粘附率以及A909在小鼠中的毒力。进一步的转录组分析表明，Tnfsf15基因在宿主感染期间由BP、AP1和SrtC基因簇介导的A909菌株致病性调节中起关键作用。
