Department of Genetics, School of Biological Sciences, Madurai Kamaraj University, Madurai, 625021, India.
National Institute of Animal Biotechnology, Hyderabad, 500032, India.
Sci Rep. 2024 Nov 22;14(1):29019. doi: 10.1038/s41598-024-80533-9.
We describe the whole-genome sequencing and comparative genomic analysis of 22 mastitis-associated NASM strains isolated from India. The mean genome size of the strains was 2.55 Mbp, with an average GC content of 32.2%. We identified 14 different sequence types (STs) among the 22 NASM strains. Of these, ST1 and ST6 of S. chromogenes were exclusively associated with bovine mastitis. Genome-wide SNP-based minimum spanning tree revealed the intricate phylogenetic relationships among NASM strains from India, categorizing them into five major clades. Interestingly, mastitis-associated strains formed separate subclades in all the NASM species studied, indicating distinct host-specific co-evolution. The study identified 32 antimicrobial resistance (AMR) genes and 53 virulence-associated genes, providing insights into the genetic factors that could contribute to the pathogenicity of NASM species. Some virulence and AMR genes were found in the predicted genomic islands, suggesting possible horizontal transfer events.
我们描述了从印度分离的 22 株乳腺炎相关 NASM 菌株的全基因组测序和比较基因组分析。这些菌株的平均基因组大小为 2.55 Mbp，平均 GC 含量为 32.2%。在 22 株 NASM 菌株中，我们鉴定出了 14 种不同的序列类型（STs）。其中，S. chromogenes 的 ST1 和 ST6 与牛乳腺炎有密切关联。基于全基因组 SNP 的最小生成树揭示了来自印度的 NASM 菌株之间错综复杂的系统发育关系，将它们分为五个主要分支。有趣的是，乳腺炎相关菌株在所有研究的 NASM 物种中形成了单独的亚分支，表明存在独特的宿主特异性共同进化。该研究鉴定了 32 个抗生素耐药（AMR）基因和 53 个与毒力相关的基因，为 NASM 物种的致病性提供了遗传因素方面的见解。一些毒力和 AMR 基因存在于预测的基因组岛中，提示可能存在水平基因转移事件。
