Two Gram-positive, anaerobic, non-spore-forming and coccoid or oval-shaped bacterial strains, namely, DN0138T and DN0266, were isolated from faecal samples of healthy Japanese people. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain DN0138T clustered with a species of the genus Blautia and was closely related to Blautia producta JCM 1471T, Blautia coccoides JCM 1395T, Blautia hominis KB1T and 'Blautia marasmi' Marseille-P2377, with sequence similarities of 98.6, 98.5, 98.8 and 98.2 %, respectively. The average nucleotide identity values were 85.3 % for B. producta JCM 1471T, 85.0 % for B. coccoides NCTC 11035T, 84.3 % for B. hominis KB1T and 84.3 % for 'B. marasmi' Marseille-P2377. The major end products of glucose metabolism were acetic acid, lactic acid and succinic acid. The genome length of strain DN0138T was 6 247 046 bp with 46.7 mol% G+C content of genome sequence. Based on their phenotypic, cellular fatty acid and phylogenetic characteristics, the three isolates represent a novel species within the genus Blautia, for which the name Blautia parvula sp. nov. is proposed. The type strain is DN0138T (=NBRC 113351T=BCRC 81349T).
Keywords: Blautia; Blautia parvula; Lachnospiraceae; faecal samples; gut microbiota.