Identification and Characterization of Two Novel Members of the Family Eubacteriaceae, Anaerofustis butyriciformans sp. nov. and Pseudoramibacter faecis sp. nov., Isolated from Human Feces

Members of <i>Eubacteriaceae</i> are involved in host health and diseases. Two Gram-stain-positive, strictly anaerobic, non-motile, non-spore-forming, and rod-shaped bacterial strains, HA2171^T and HA2172^T, were isolated from the feces of Chinese healthy donors. Based on 16S rRNA gene sequences, HA2171^T and HA2172^T belonged to the family <i>Eubacteriaceae</i>. Physiological and biochemical characterizations indicated that HA2171^T and HA2172^T were neutrophilic, mesophilic, and tolerant to low-concentration NaCl. The major cellular fatty acids (>10.0%) of HA2171^T were C_16:0, C_14:0, C_18:1ω7c, and C_17:0 2-OH, and those of HA2172^T were C_14:0 and C_16:0. MK-6 was the respiratory quinone in both strains. Phylogenetic and phylogenomic analyses showed that HA2171^T was closest to <i>Anaerofustis stercorihominis</i> ATCC BAA-858^T and that HA2172^T as closest to <i>Pseudoramibacter alactolyticus</i> ATCC 23263^T. Genome annotation revealed that the HA2171^T and HA2172^T were able to metabolize carbohydrates and produce acetate and butyrate. HA2172^T 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^T and HA2172^T represent two novel species, and the names <i>Anaerofustis butyriciformans</i> sp. nov. and <i>Pseudoramibacter faecis</i> sp. nov. are proposed.