Emendation of genus Collinsella and proposal of Collinsella stercoris sp. nov. and Collinsella intestinalis sp. nov.

Collinsella aerofaciens-like strains isolated from human faeces were characterized by biochemical tests, cell wall murein analysis and 16S rDNA analysis. The results indicated that these strains are phylogenetically a member of the family Coriobacteriaceae and close to the genus Collinsella. Their phenotypic characters resembled those of Collinsella aerofaciens. Determination of DNA-DNA relatedness showed that these strains could be divided into two groups (groups 1 and 2). Collinsella aerofaciens and both new groups have A4-type cell wall murein. Based on their phenotypic and phylogenetic characters, two new species of the genus Collinsella are proposed for the isolated strains: Collinsella stercoris for group 1 and Collinsella intestinalis for group 2. Species-specific PCR primer sets for these two species were also constructed. Using these primer sets, Collinsella stercoris and Collinsella intestinalis can be identified easily and rapidly.