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

Abstract

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 <i>Clostridiales</i> with <i>Dorea longicatena</i> ATCC 27755^T (94.9 % sequence identity), <i>Ruminococcus gnavus</i> ATCC 29149^T (94.8%) and <i>Clostridium scindens</i> 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 (<i>D. longicatena</i>, <i>Ruminococcus gnavus</i>, <i>C. scindens</i>, <i>Dorea formicigenerans</i>, <i>Ruminococcus lactaris</i>, <i>Clostridium hylemonae</i>, <i>Merdimonas faecis</i>, <i>Faecalicatena contorta</i> and <i>Faecalicatena fissicatena</i>). 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} <i>cis</i>9 (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 H₂ 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 <i>Sporofaciens musculi</i> gen. nov., sp. nov. is proposed. The type strain is WCA-9-b2^T (=DSM 106039^T=CECT 30156^T).