Coprobacter secundus subsp. similis subsp. nov. and Solibaculum mannosilyticum gen. nov., sp. nov., isolated from human feces

An obligately anaerobic, Gram-stain-negative, rod-shaped bacterium, designated strain 2CBH44(T), was isolated from the fecal sample of a healthy Japanese man. This strain was initially assigned as a novel species of the genus Coprobacter based on the 16S rRNA gene sequence similarities compared with other Coprobacter species. The 16S rRNA gene sequence analysis revealed strain 2CBH44(T) had relatively low 16S rRNA gene sequence similarity (97.5%) to Coprobacter secundus 177(T). However, strain 2CBH44(T) showed 96.9% average nucleotide identity value with C. secundus 177(T), indicating that strain 2CBH44(T) and C. secundus 177(T) belong to the same species. On the other hand, the digital DNA-DNA hybridization value between strain 2CBH44(T) and C. secundus 177(T) was 73.5%, indicating that strain 2CBH44(T) is a subspecies of C. secundus. Another anaerobic, Gram-stain-variable, rod-shaped bacterium, designated strain 12CBH8(T), was also isolated from human feces. Strain 12CBH8(T) had significantly low 16S rRNA gene sequence similarities (<92.0%) to the validated bacterial species within the family Oscillospiraceae. The percentage of conserved protein values between the genome of strain 12CBH8(T) and that of the validated related taxa were <50%, suggesting that strain 12CBH8(T) belongs to a novel genus. On the basis of the collected data, strain 2CBH44(T) represents a novel subspecies of C. secundus, for which the name Coprobacter secundus subsp. similis subsp. nov. (type strain 2CBH44(T) = JCM 34079(T) = DSM 111570(T)) is proposed. Strain 12CBH8(T) represents a novel species of a novel genus, for which the name Solibaculum mannosilyticum gen. nov., sp. nov. (type strain 12CBH8(T) = JCM 34081(T) = DSM 111571(T)) is proposed.

Automated summary

Two novel bacterial strains were isolated from human feces in this study. Strain 2CBH44(T) was identified as a subspecies of Coprobacter secundus, named as Coprobacter secundus subsp. similis subsp. nov. Strain 12CBH8(T) belonged to a novel genus and species, named as Solibaculum mannosilyticum gen. nov., sp. nov.