Two carbon dioxide-requiring, gliding, Gram-stain-negative strains, designated p1a2T and 051621, were isolated from subgingival plaque in association with severe periodontitis. The 16S rRNA gene sequence analysis revealed that they represented members of the genus Capnocytophaga and had less than 96.4 % pairwise similarity with species with validly published names in this genus. The whole-genome sequences of those strains had less than 91.9 % average nucleotide identity and 48.4 % digital DNA-DNA hybridization values with the other type strains of species of the genus Capnocytophaga, both below the species delineation threshold. The results of pan-genomic analysis indicated that p1a2T and 051621 shared 765 core gene families with the other ten species in this genus, and the numbers of strain-specific gene families were 493 and 455, respectively. The major fatty acids were iso-C15 : 0 and C16 : 0. A combination of phenotypic, chemotaxonomic, phylogenetic and genotypic data clearly indicate that p1a2T and 051621 should be considered to represent a novel species of the genus Capnocytophaga, for which the name Capnocytophaga periodontitidis sp. nov. is proposed. The type strain is p1a2T (=CGMCC 1.17337T=JCM 34126T).
Keywords: Capnocytophaga periodontitidis sp. nov; chemotaxonomy; genotype; phylogenetics; physiology; polyphasic taxonomy.