Pathogenicity and genomic characteristics of a Streptococcus pluranimalium strain isolated from bovine

Abstract:

[Background] Streptococcus pluranimalium was initially reported by Devriese et al. in 1999 as a potential zoonotic pathogen with a broad range of hosts. Although this pathogen has been isolated and identified from infected tissues of several species, including cattle, sheep, pigs, and broilers, there are few studies reporting its pathogenicity, antibiotic resistance, and genomics, which remain to be studied. [Objective] This study aims to identify a S. pluranimalium strain isolated from bovine respiratory tract and analyze its pathogenicity and antibiotic resistance. The basic characteristics of the genome and some virulence factors and antibiotic resistance genes were identified by genome sequencing. [Methods] Nasal swabs were collected from diseased cattle for identification of the pathogenic bacteria by 16S rRNA sequencing. Furthermore, the pathogenicity of the isolate in rabbits and the drug susceptibility of the strain were studied. Illumina sequencing and assembly were carried out to obtain an overview of the genome of the strain. Swiss-Prot, NR, GO, COG, KEGG, CAZy, TCDB, and Pfam were used for gene annotation and function analysis. PHI, VFDB and CARD were employed to annotate the virulence factors and drug resistance genes of the strain. [Results] S. pluranimalium Bov5 was successfully isolated, which induced pulmonary septal thickening and inflammatory cell infiltration in the rabbit lung tissue. The strain was resistant to lincomycin and clindamycin and showcased intermediate resistance to streptomycin. The genome size of the strain was determined to be 2 038 579 bp (2.04 Mb). A total of 1 981 coding genes were annotated, including 100 virulence factors, 28 genes conferring enhanced pathogenicity due to mutations, and 83 antibiotic resistance genes. [Conclusion] We isolated a bovine-derived S. pluranimalium strain with strong pathogenicity, constructed the genome framework of the strain, and mined the virulence and antibiotic resistance genes. The findings laid a foundation for further studying the pathogenic genes and antibiotic resistance genes of S. pluranimalium.