Common Features and Intra-Species Variation of Strains, and Emended Description of the Species.

is a new species coined in 2020 as the fifth species of genus , which includes . The species is predicted as a minor but common member of skin microbiome and includes a group tentatively named as "". The description of the species has been provided only with a single strain. To establish the characteristics of and search for possible disease-related subtypes, we investigated the biochemical characteristics of eight live strains and performed in silico comparison of nine genomes. The common features, which included the morphology of Gram-stain positive short rods, the negativity of phenylalanine arylamidase, and several unique MALDI-TOF MS spectral peaks, were considered useful in laboratory identification. Pairwise comparisons of the genomes by in silico DNA-DNA hybridization showed similarity values of 98.1% or larger, which were far higher than the subspecies cutoff of 79-80%. The gene sequences of thirteen isolates and genomes were identical. Their gene sequences were identical except for two strains, HM-510 (HL037PA2) and Marseille-P5998, which showed unique one-nucleotide polymorphisms. The biochemical features using API kits were slightly different among the isolates but far closer than those of the nearest other species, and . Spectra of MALDI-TOF mass spectrometry showed slight differences in the presence of / 10,512 (10 kD chaperonin GroS) and three other peaks, further clustering the eight isolates into three subtypes. These results indicated that these isolates did not separate to form subspecies-level clusters, but subtyping is possible by using gene sequences or MALDI-TOF mass spectrometry spectra. Moreover, this work has confirmed that a group "" is included in .