Abstract
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-A3T, was most closely related to Allobaculum stercoricanis, with 16S rRNA gene sequence similarity values of 87.7 %. A second group, represented by NYU-BL-A4T, 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-A3T were C16 : 0 and C18 : 0, and those of strain NYU-BL-A4T were C10 : 0, C16 : 0, C18 : 0 and C18 : 1ω9c. The two groups could also be distinguished by multiple biochemical reactions, with the group represented by NYU-BL-A4T being considerably more active. Based on phylogenetic, biochemical and chemotaxonomic criteria, two novel genera are proposed, Ileibacterium valens gen. nov., sp. nov. with NYU-BL-A3T (=ATCC TSD-63T=DSM 103668T) as the type strain and Dubosiella newyorkensis gen. nov., sp. nov. with NYU-BL-A4T (=ATCC TSD-64T=DSM 103457T) as the type strain.