Abstract
The obligately anaerobic, Gram-stain-positive coccobacilli strains OB7620(T) and OB7656(T) were isolated from faecal samples of healthy Japanese volunteers. Strain OB7620(T) showed the highest 16S rRNA gene sequence similarity to Coprococcus comes ATCC 27758(T) (98.4%) and Clostridium nexile DSM 1787(T) (96.3%). Strain OB7656(T) showed the highest 16S rRNA gene sequence similarity to 'Gluceribacter canis' NATH-2371(T) (97.7%), C. nexile DSM 1787(T) (94.8%) and Faecalimonas umbilicata EGH7(T) (94.8%). These findings indicate that the two strains represent novel species. Genomic analysis clarified the phylogenetic relationship of C. comes with the species cluster designated as Coprococcus sensu stricto, which includes the type species, C. eutactus. As C. comes is distinct from the species of Coprococcus sensu stricto, C. comes is reclassified into a novel genus, Allocoprococcus, as Allocoprococcus comes gen. nov., comb. nov. Although strain OB7620(T) is closely related to C. comes, it is a distinct species. Therefore, we propose the name Allocoprococcus similis gen. nov., sp. nov. The type strain is OB7620(T) (=DSM 118890(T)=JCM 37173(T)). Because Coprococcus catus differs from Coprococcus sensu stricto, it has been placed in a novel genus, Pseudocoprococcus, as Pseudocoprococcus catus gen. nov., comb. nov. We also concluded that Coprococcus immobilis and Coprococcus intestinihominis are the same species and belong to the new genus Pseudocoprococcus. As C. immobilis has priority, we propose the name Pseudocoprococcus immobilis gen. nov., comb. nov. We also concluded that C. nexile and Clostridium phoceensis are the same species in the genus Faecalimonas. As C. nexile has priority, we propose the name Faecalimonas nexilis comb. nov. Coprococcus mobilis and 'G. canis' should also be reclassified within the genus Faecalimonas. Therefore, we propose the name Faecalimonas mobilis comb. nov. and Faecalimonas canis sp. nov. As strain OB7656(T) is related to 'G. canis' but is a different species, we propose the name Faecalimonas hominis sp. nov. The type strain is OB7656(T) (=DSM 118889(T)=JCM 37172(T)).