Alistipes communis sp. nov., Alistipes dispar sp. nov. and Alistipes onderdonkii subsp. vulgaris subsp. nov., isolated from human faeces, and creation of Alistipes onderdonkii subsp. onderdonkii subsp. nov.

Three groups of Gram-stain-negative, obligately anaerobic, rod or coccoid-shaped bacteria, which were phylogenetically assigned in the genus Alistipes belonging to the family Rikenellaceae in the phylum Bacteroidetes , were isolated from the faecal samples of healthy Japanese humans. Group I (strains 5CBH24(T) and 6CPBBH3) showed highest 16S rRNA gene sequence similarity to 'Alistipes obesi' ph8(T) (99.73%). Group II (strain 5CPEGH6(T)) was related to Alistipes shahii WAL 8301(T) (96.82%). Ten strains of group III (3BBH6(T), 5CPYCFAH4, 5NYCFAH2 and others) were related to Alistipes onderdonkii DSM 19147(T) (98.96%). Group I could be differentiated from other strains by the ability to hydrolyse aesculin and the lack of catalase activity. Strain 5CPEGH6(T) could be differentiated from A. shahii JCM 16773(T) by the inability to hydrolyse aesculin and the lack of catalase activity, and so on. Phenotypic characteristics of group III were similar to those of A. onderdonkii JCM 16771(T). Strains 5CBH24(T), 6CPBBH3 and 'A. obesi' ph8(T) shared 98.898.9?% average nucleotide identity (ANI) with each other. In addition, the in silico DNADNA hybridization (DDH) values among three strains were 86.7-89.4%. Strain 5CPEGH6(T) showed relatively low values (<= 84.4% for ANI ; <= 26.2% for DDH) with other strains. Three strains in the group III (3BBH6(T), 5CPYCFAH4 and 5NYCFAH2) shared 97.999.9% ANI with each other. These three strains showed 96.9-97.3% ANI with A. onderdonkii DSM 19147(T). The DDH values of strains 3BBH6(T), 5CPYCFAH4 and 5NYCFAH2 among themselves were 80.5-99.8%, while those compared to A. onderdonkii DSM 19147(T) were 71.0-73.4%. On the basis of the collected data, three novel species, Alistipes communis sp. nov. (5CBH24(T)=JCM 32850(T)=DSM 108979(T)), Alistipes dispar sp. nov. (5CPEGH6(T)=JCM 32848(T)=DSM 108978(T)) and Alistipes onderdonkii subsp. vulgaris subsp. nov. (3BBH6(T)=JCM 32839(T)=DSM 108977(T)), are proposed.