sp. nov., a commensal spirochaete isolated from human faeces.

A Gram-stain-negative, obligatory anaerobic spirochaete (RCC2812) was isolated from a faecal sample obtained from an individual residing in a remote Amazonian community in Peru. The bacterium showed highest 16S rRNA gene sequence similarity to the pig intestinal spirochete (89.48 %). Average nucleotide identity values between strain RCC2812 and all available genomes from validated type strains were all <73 %, thus clearly lower than the species delineation threshold. The DNA G+C content of RCC2812 was 41.24 mol%. Phenotypic characterization using the API-ZYM and API 20A systems confirmed the divergent position of this bacterium within the genus . Strain RCC2812 could be differentiated from the phylogenetically most closely related by the presence of alkaline phosphatase and α -glucosidase activities. Unlike , strain RCC2812 grew equally well with or without serum. Strain RCC2812 is the first commensal isolated from the human faecal microbiota of remote populations, and based on the collected data represents a novel species for which the name sp. nov. is proposed. The type strain is RCC2812 (=LMG 31794=CIP 111910).