Description of subsp. subsp. nov., an anaerobic bacterium isolated from human faeces, and emended description of .

A recent metagenomic survey has revealed an unknown bacterial clade within the species to be significantly more prevalent in non-urbanized populations, compared to urbanized ones. We isolated and characterized a strain of this clade from the stool of a healthy adult volunteer. Strain CMD8551 is strictly anaerobic, appears as long chains of Gram-positive rods and produces acetate in the presence of glucose. The lipidomic profile showed a higher proportion of saturated lipid species amongst the detected phospholipids. The whole genome is 2,320,430 bp long and has a G+C content of 33.7 mol% with 2,239 CDSs. A phylogenetic analysis comparing the sequences of the strain CMD8551 with publicly available reference genomes from the genus revealed that the CMD8551 isolate, together with other isolate genomes, forms a distinct subspecies of and has an average nucleotide identity lower than 94% with respect to the previously described subsp. . Given the phenotypic, chemotaxonomic and phylogenetic characteristics of the newly isolated CMD8551 (=DSM 118469=LMG 33725=CIP 112509) that clearly differ from those of the subsp. type strain RCA14-39, we propose it as the type strain of a novel subspecies of , with the name subsp. subsp. nov.