Identification and Characterization of Two Novel Members of the Family , sp. nov. and sp. nov., Isolated from Human Feces.

Members of are involved in host health and diseases. Two Gram-stain-positive, strictly anaerobic, non-motile, non-spore-forming, and rod-shaped bacterial strains, HA2171 and HA2172, were isolated from the feces of Chinese healthy donors. Based on 16S rRNA gene sequences, HA2171 and HA2172 belonged to the family . Physiological and biochemical characterizations indicated that HA2171 and HA2172 were neutrophilic, mesophilic, and tolerant to low-concentration NaCl. The major cellular fatty acids (>10.0%) of HA2171 were C, C, C, and C 2-OH, and those of HA2172 were C and C. MK-6 was the respiratory quinone in both strains. Phylogenetic and phylogenomic analyses showed that HA2171 was closest to ATCC BAA-858 and that HA2172 as closest to ATCC 23263. Genome annotation revealed that the HA2171 and HA2172 were able to metabolize carbohydrates and produce acetate and butyrate. HA2172 contains genes associated with hydrogen sulfide production, which is a potential risk for diseases. Based on the phylogenetic, phenotypic, and chemotaxonomic characteristics, we propose that HA2171 and HA2172 represent two novel species, and the names sp. nov. and sp. nov. are proposed.