Description of two novel members of the family Erysipelotrichaceae: Ileibacterium valens gen. nov., sp nov and Dubosiella newyorkensis, gen. nov., sp nov., from the murine intestine, and emendation to the description of Faecalibacterium rodentium

To better characterize murine intestinal microbiota, a large number (187) of Gram-positive-staining, rod- and coccoid-shaped, and facultatively or strictly anaerobic bacteria were isolated from small and large intestinal contents from mice. Based on 16S rRNA gene sequencing, a total 115 isolates formed three phylogenetically distinct clusters located within the family Erysipelotrichaceae. Group 1, as represented by strain NYU-BL-A3(T), was most closely related to Allobaculum stercoricanis, with 16S rRNA gene sequence similarity values of 87.7 %. A second group, represented by NYU-BL-A4(T), was most closely related to Faecalibaculum rodentium, with 86.6% 16S rRNA gene sequence similarity. A third group had a nearly identical 16S rRNA gene sequence (99.9 %) compared with the recently described Faecalibaculum rodentium, also recovered from a laboratory mouse; however, this strain had a few differences in biochemical characteristics, which are detailed in an emended description. The predominant (> 10 %) cellular fatty acids of strain NYU-BL-A3(T) were C-16 : 0 and C-18 : 0, and those of strain NYU-BL-A4(T) were C-10 : 0, C1(6 : 0), C1(8 : 0) and C-18 : 1 omega 9c. The two groups could also be distinguished by multiple biochemical reactions, with the group represented by NYU-BL-A4(T) being considerably more active. Based on phyllogenetic, biochemical and chemotaxonomic criteria, two novel genera are proposed, Ileibacterium valens gen. nov., sp. nov. with NYU-BL-A3(T) (= ATCC TSD-63(T) = DSM 103668(T)) as the type strain and Dubosiella newyorkensis gen. nov., sp. nov. with NYU-BL-A4(T) (= ATCC TSD-64(T) = DSM 103457(T)) as the type strain.