Faecalimonas umbilicata gen. nov., sp. nov., isolated from human faeces, and reclassification of Eubacterium contortum, Eubacterium fissicatena and Clostridium oroticum as Faecalicatena contorta gen. nov., comb. nov., Faecalicatena fissicatena comb. nov. and Faecalicatena orotica comb. nov.

Two bacterial strains, designated EGH7T and TSAH33, were isolated from human faeces and characterized by using a polyphasic taxonomic approach that included analysis of morphology, phenotypic and biochemical features, cellular fatty acid profiles and phylogenetic position based on 16S rRNA and hsp60 gene sequence analyses. The results of 16S rRNA gene sequence analysis indicated that these strains represented members of the family Lachnospiraceae and formed a monophyletic cluster near Eubacterium contortum JCM 6483T (95 % sequence similarity), Ruminococcus gnavus JCM 6515T (95 %), Clostridium oroticum JCM 1429T (95 %), Eubacterium fissicatena JCM 31501T (95 %) and Clostridium nexile JCM 31500T (94 %). The results of a hsp60 gene sequence analysis supported the phylogenetic tree based on the 16S rRNA gene sequence, with a sequence similarity value of between 77.9 and 84.8 % to the five strains listed above. The novel strains were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-stain-positive cocco-bacilli. The strains formed characteristic umbilicated colonies on EG agar plates. The major cellular fatty acids were C18 : 1ω9c, C16 : 0 and C18 : 1ω9c dimethyl acetal (DMA). EGH7T and TSAH33 have DNA G+C contents of 46.9 and 45.5 mol%, respectively. On the basis of these data, strains EGH7T and TSAH33 represent a novel species of a novel genus, for which the name Faecalimonas umbilicata gen. nov., sp. nov. is proposed. The type strain of F. umbilicata is EGH7T (=JCM 30896T=DSM 103426T).