Streptococcus bovipulmonis sp. nov., a pathogenic bacterium isolated from a dead dairy cow with hemorrhagic pneumonia

A strain of Gram-stain-positive, oxidase- and catalase-negative, facultative anaerobic coccus-shaped bacterium, designated as ZY171113^T, was isolated from lung of a dead dairy cow with hemorrhagic pneumonia in Yunnan Province, southwest China. The pairwise comparisons of 16S rRNA gene sequences indicated that the strain share the highest similarities to Streptococcus suis CCUG 7984^T and S. gallinaceus CCUG 42692^T with 96.2 and 96.0 %, respectively, suggesting the strain belongs to the genus Streptococcus. The phylogenetic analysis of 16S rRNA gene sequences and phylogenomic analysis of 113 single-copy gene sequences placed the strain as a distinct clade within the genus Streptococcus. The genomic orthologous average nucleotide identity and digital DNA-DNA hybridization values between strain ZY171113^T and its close relatives within the genus Streptococcus were ≤ 72.9 % and ≤ 28.7 %, which were below the cut-off values for species delineation. The optimal growth of strain ZY171113^T occurred at 37 °C, at pH 7.0 and in the presence of 1.0 % (w/v) NaCl. The genomic DNA G+C content of strain ZY171113^T was 48.8 mol%, which was higher than the upper limit of the range 33.1-44.6 mol% of the type strains within the genus Streptococcus. The strain ZY171113^T shared the major fatty acids C_14:0, C_16:0, C_18:0 and C_18:1 ω9c, and the major polar lipids phosphatidylglycerol, monogalactosyldiacylglycerol, ether-linked phosphatidylcholine and phosphatidylinositol with its closest relatives S. gallinaceus CCUG 42692^T and S. suis CCUG 7984^T. The strain harbored the sole Lancefield group D antigen. Based on the phenotypic, genotypic and chemotaxonomic features, strain ZY171113^T represents a novel species within the genus Streptococcus, for which the name Streptococcus bovipulmonis sp. nov. is proposed, with strain ZY171113^T (=NBRC 116579^T=CCTCC AB 2023267^T) as the type strain. The pathogenicity test indicated that strain S. bovipulmonis ZY171113^T could induce respiratory disease in mice. These results confirmed that the novel species S. bovipulmonis is a pathogenic bacterium, and suggested that it may be a new pathogen of the respiratory disease in cattle.