Sporofaciens musculi gen. nov., sp. nov., a novel bacterium isolated from the caecum of an obese mouse

A bacterial strain, designated WCA-9-b2(T), was isolated from the caecal content of an 18-week-old obese C57BL/6NTac male mouse. According to phenotypic analyses, the isolate was rod-shaped, strictly anaerobic, spore-forming, non-motile and Gram-stain-positive, under the conditions tested. Colonies were irregular and non-pigmented. Analysis of the 16S rRNA gene sequence indicated that the isolate belonged to the order Clostridiales with Dorea longicatena ATCC 27755(T) (94.9% sequence identity), Ruminococcus gnavus ATCC 29149(T) (94.8%) and Clostridium scindens ATCC 35704(T) (94.3%) being the closest relatives. Whole genome sequencing showed an average nucleotide identity <74.23 %, average amino acid identity <64.52-74.67 % and percentage of conserved proteins values <50% against the nine closest relatives (D. longicatena, Ruminococcus gnavus, C. scindens, Dorea formicigenerans, Ruminococcus lactaris, Clostridium hylemonae, Merdimonas faecis, Faecalicatena contorta and Faecalicatena fissicatena). The genome-based G+C content of genomic DNA was 44.4 mol%. The major cellular fatty acids were C-16:0 (24.5%), C-18:1 cis9 (19.8 %), C-16:0 DMA (11.7%), C-18:0 (8.4%) and C-14:0 (6.6%). Respiratory quinones were not detected. The predominant metabolic end products of glucose fermentation were acetate and succinate. Production of CO2 and H-2 were detected. Based on these data, we propose that strain WCA-9-b2(T) represents a novel species within a novel genus, for which the name Sporofaciens musculi gen. nov., sp. nov. is proposed. The type strain is WCA-9-b2(T) (=DSM 106039(T)=CECT 30156(T)).