Actinomyces capricornis sp. nov., isolated from the oral cavity of a Japanese serow

A novel Gram‐positive, facultatively anaerobic, rod‐shaped, nonspore forming, nonmotile organism was isolated from a Japanese serow oral cavity. Designated strain MAS‐1T, it is most closely related to Actinomyces bowdenii DSM 15435T, with which it shares 98.07% sequence homology in the 16S ribosomal RNA gene. The primarily detected cellular fatty acids in strain MAS‐1T were C16:0 and C18:1w9c. The predominant respiratory quinone was MK‐9 (H4). The major polar lipids were phosphatidylcholines, phosphatidylinositols, and glycophospholipids. The genomic DNA GC content of the isolate was 71.3 mol%. The digital DNA–DNA hybridization and average nucleotide identity values between MAS‐1T and its related species were 23.5%–39.5% and 82.11%–91.01%, respectively, which were below the threshold (70% and 95%, respectively) for species delineation, indicating that strain MAS‐1T represents a novel species. Strain MAS‐1T can be differentiated from A. bowdenii by their reactions to naphthol‐AS‐BI‐phosphohydrolase, α‐galactosidase, β‐galactosidase, and N‐acetyl‐β‐glucosaminidase, as well as differing acid production from glycogen. Based on the results of genotypic, phenotypic, and biochemical analyses, herein it is proposed that the identified bacteria can be classified as a novel species, Actinomyces capricornis sp. nov., strain MAS‐1T (=JCM 34236T = DSM 111732T).