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 Eubacteriaceae are involved in host health and diseases. Two Gram-stain-positive, strictly anaerobic, non-motile, non-spore-forming, and rod-shaped bacterial strains, HA2171T and HA2172T, were isolated from the feces of Chinese healthy donors. Based on 16S rRNA gene sequences, HA2171T and HA2172T belonged to the family Eubacteriaceae. Physiological and biochemical characterizations indicated that HA2171T and HA2172T were neutrophilic, mesophilic, and tolerant to low-concentration NaCl. The major cellular fatty acids (>10.0%) of HA2171T were C16:0, C14:0, C18:1ω7c, and C17:0 2-OH, and those of HA2172T were C14:0 and C16:0. MK-6 was the respiratory quinone in both strains. Phylogenetic and phylogenomic analyses showed that HA2171T was closest to Anaerofustis stercorihominis ATCC BAA-858T and that HA2172T as closest to Pseudoramibacter alactolyticus ATCC 23263T. Genome annotation revealed that the HA2171T and HA2172T were able to metabolize carbohydrates and produce acetate and butyrate. HA2172T 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 HA2171T and HA2172T represent two novel species, and the names Anaerofustis butyriciformans sp. nov. and Pseudoramibacter faecis sp. nov. are proposed.