Sellimonas catena sp. nov., isolated from human faeces

Obligately anaerobic, Gram-stain-positive, small-chain coccobacilli, strains 12EGH17^T and 18CBH55, were isolated from faecal samples of healthy Japanese humans. Strain 12EGH17^T showed the highest 16S rRNA gene sequence similarity to Sellimonas intestinalis BR72^T (95.5 %), Coprococcus comes ATCC 27758^T (94.4 %) and Clostridium nexile DSM 1787^T (93.7 %). The percentage of conserved proteins values between the genome of strain 12EGH17^T and that of the members of the genus Sellimonas were >54 %, suggesting that strain 12EGH17^T belongs to the genus Sellimonas. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strains 12EGH17^T and 18CBH55 were higher than the cut-off values of species demarcation (90 % dDDH and 99 % ANI), indicating these two strains are the same species. However, the dDDH and ANI values of these strains were lower than the cut-off values of species demarcation against other strains (<30 % dDDH and <79 % ANI). These results indicate that the isolates should be considered to represent a new species of the genus Sellimonas. The isolates were differentiated from the type species, S. intestinalis, by the ability of aesculin hydrolysis. Based on the collected data, strains 12EGH17^T and 18CBH55 represent a novel species in the genus Sellimonas, for which the name Sellimonas catena sp. nov. is proposed. The type strain of S. catena is 12EGH17^T (=JCM 35622^T=DSM 114916^T).