Clostridium fessum sp. nov., isolated from human faeces

An obligately anaerobic, Gram-stain-positive and spore-forming strain, SNUG30386(T) was isolated from a faecal sample of a healthy Korean subject. The strain formed a round ivory-coloured colony and cells were chained rods with tapered ends, approximately 2.0-2.5x0.6-0.8 mu m in size. The taxonomic analysis indicated that strain SNUG30386(T) was within the family Lachnospiraceae. According to the 16S rRNA gene sequence similarity, the closest species to strain SNUG30386(T) was Clostridium symbiosum (95.6%), followed by Enterocloster asparagiformis (94.8%), Enterocloster clostridioformis (94.8%) and Enterocloster lavalensis (94.6%). The evolutionary tree based on 16S rRNA gene sequences demonstrated that strain SNUG30386(T) had split apart at a unique branch point far from other close relatives. Its DNA G+C content was 48.3 mol% calculated from the whole genome sequence. The major cellular fatty acids were C-16:0 and C-14:0. Compared to those of the closely related species, strain SNUG30386(T) showed distinct biochemical activities such as being unable to utilize most of carbon sources except D-glucose and l-arabinose. As a result, based on its unique phylogenetic clade and taxonomic characteristics, we conclude that strain SNUG30386(T) represents a novel species within the genus Clostridium, for which the name Clostridium fessum sp. nov. is proposed. The type strain of the novel species is SNUG30386(T) (=KCTC 15633(T)= JCM 32258(T)).

Automated summary

Strain SNUG30386(T) is an obligately anaerobic, Gram-stain-positive and spore-forming bacterium belonging to the family Lachnospiraceae. Phylogenetic analysis based on 16S rRNA gene sequences suggests that it represents a novel species within the genus Clostridium, which has been proposed as Clostridium fessum sp. nov.