Roseburia intestinalis sp. nov., a novel saccharolytic, butyrate-producing bacterium from human faeces.

Five strains of butyrate-producing, anaerobic, gram-positive bacteria were isolated from human faecal material. These strains were slightly curved rods that showed motility by means of multiple subterminal flagella. The DNA G + C content of the strains was 29-31 mol%. A detailed investigation of the phenotypic and phylogenetic characteristics of the strains revealed that they represent a novel species of anaerobic, low-G+C-content, butyrate-producing bacterium that shows net acetate utilization during growth on media containing carbohydrates and short-chain fatty acids. The 16S rRNA gene sequences of the five isolates were determined and they confirmed that these strains were closely related to each other. Phylogenetic analysis indicated that the most closely related species are Eubacterium rectale, Eubacterium oxidoreducens and Roseburia cecicola, members of cluster XIVa of the Clostridium subphylum of gram-positive bacteria, although they share less than 95% sequence identity with the novel strains. It is proposed that a novel species, Roseburia intestinalis sp. nov., be created, with strain L1-82T (= DSM 14610T = NCIMB 13810T) as the type strain.