LAUSR

To better characterize murine intestinal microbiota, a large number (187) of Gram-positive-staining, rodand coccoidshaped, 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, 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, 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 were C16 : 0 and C18 : 0, and those of strain NYU-BL-A4 were C10 : 0, C16 : 0, C18 : 0 and C18 : 1!9c. The two groups could also be distinguished by multiple biochemical reactions, with the group represented by NYU-BL-A4 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-A3 (=ATCC TSD-63=DSM 103668) as the type strain and Dubosiella newyorkensis gen. nov., sp. nov. with NYU-BL-A4 (=ATCC TSD-64=DSM 103457) as the type strain. High-throughput sequencing technology has markedly accelerated research on microbes in complex ecosystems, including host-associated bacteria, collectively known as the microbiota, that have roles in shaping health and disease [1–3]. With untested potential microbe–host associations being identified on a regular basis, there is increasing need to culture and characterize members of novel bacterial taxa to further hypothesis-driven research. In particular, the family Erysipelotrichaceae is emerging as a group of bacteria that may influence host metabolism and inflammatory diseases [4, 5], and closely related species have been associated with a high-fat diet [6], promotion of obesity [7] or protection from weight gain on a high fat diet [4]. The family Erysipelotrichaceae was first described by Verbarg et al. [8] to include a number of Gram-stain-positive, slender or filamentous rods with a b-cross-linking type peptidoglycan belonging to the genus Erysipelothrix, with Erysipelothrix rhusiopathiae listed as the type species [8]. While the family was originally described to have facultatively anaerobic and microaerophilic organisms, it has recently been emended by Tegtmeier et al. [9] to include strictly anaerobic organisms. Recent additions to the family Erysipelotrichaceae include Author affiliations: Department of Medicine, NYU Langone Medical Center, New York, NY 10016, USA; Department of Microbiology, NYU Langone Medical Center, New York, NY 10016, USA; Department of Neurology, Ann Romney Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA; R. M. Alden Research Laboratory, Culver City, CA 90230, USA; Department of Microbiology and Plant Biology, University of Oklahoma, Norman, USA; New York Harbor Department of Veterans Affairs Medical Center, New York, NY 10010, USA. *Correspondence: Laura M. Cox, [email protected]