Claveliimonas bilis gen. nov., sp. nov., deoxycholic acid-producing bacteria isolated from human faeces, and reclassification of Sellimonas monacensis Zenner et al. 2021 as Claveliimonas monacensis comb. nov.

Abstract

Obligately anaerobic, Gram-stain-positive, bacilli, strains 12BBH14T, 9CFEGH4 and 10CPCBH12, were isolated from faecal samples of healthy Japanese people. Strain 12BBH14T showed the highest 16S rRNA gene sequence similarity to Sellimonas monacensis Cla-CZ-80T (97.5 %) and ‘Lachnoclostridium phocaeense’ Marseille-P3177T (97.2 %). Strain 12BBH14T was also closely related to Eubacterium sp. c-25 with 99.7 % 16S rRNA gene sequence similarity. The 16S rRNA gene sequence analysis showed that strains 12BBH14T, 9CFEGH4 and 10CPCBH12 formed a monophyletic cluster with Eubacterium sp. c-25. Near this monophyletic cluster, S. monacensis Cla-CZ-80T and ‘L. phocaeense’ Marseille-P3177T formed a cluster and did not form a cluster with other Sellimonas species. The digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strains 12BBH14T, 9CFEGH4, 10CPCBH12 and Eubacterium sp. c-25 were higher than the cut-off values of species demarcation (>88 % dDDH and >98 % ANI), indicating that these four strains are the same species. On the other hand, the dDDH and ANI values of these strains were lower than the cut-off values of species demarcation against other strains (<29 % dDDH and <76 % ANI). Moreover, the average amino acid identity values among these strains were higher than the genus boundary. These results indicate that the isolates should be considered to belong to a new genus of the family Lachnospiraceae . Based on the collected data, strains 12BBH14T, 9CFEGH4 and 10CPCBH12 represent a novel species of a novel genus, for which the name Claveliimonas bilis gen. nov., sp. nov. is proposed. The type strain of C. bilis is 12BBH14T (=JCM 35899T=DSM 115701T). Eubacterium sp. c-25 belongs to C. bilis. In addition, S. monacensis is transferred to the genus Claveliimonas as Claveliimonas monacensis comb. nov.