Alistipes inops sp. nov. and Coprobacter secundus sp. nov., isolated from human faeces

Abstract

Culture-based study of the faecal microbiome in two adult female subjects revealed the presence of two obligately anaerobic, non-spore-forming, rod-shaped, non-motile, Gram-negative bacterial strains that represent novel species. The first strain, designated 627T, was a fastidious, slow-growing, indole-positive bacterium with a non-fermentative type of metabolism. The strain was characterized by the production of acetic and succinic acids as metabolic end products, the prevalence of iso-C15 : 0 fatty acid and the presence of menaquinones MK-10 and MK-11. The DNA G+C content was found to be 56.6 mol%. The second strain, designated 177T, was capable of fermenting a rich collection of carbohydrate substrates, producing acetic acid as a terminal product. The strain was indole-negative and resistant to bile. The major cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0 (in a 1 : 1 ratio) and the predominant menaquinone was MK-11. The DNA G+C content was 37.8 mol%. A phylogenomic analysis of the draft genomes of strains 627T and 177T placed these bacteria in the genera Alistipes (family Rikenellaceae) and Coprobacter (family Porphyromonadaceae), respectively. On the basis of the phenotypic and genotypic properties of strains 627T and 177T, we conclude that these strains from human faeces represent two novel bacterial species, for which the names Alistipes inops sp. nov. (type strain 627T = DSM 28863T = VKM B-2859T) and Coprobacter secundus sp. nov. (type strain 177T = DSM 28864T = VKM B-2857T) are proposed.