Murimonas intestini gen. nov., sp nov., an acetate-producing bacterium of the family Lachnospiraceae isolated from the mouse gut

Three strains of an anaerobic, Gram-stain-positive coccobacillus were isolated from the intestines of mice. These strains shared 100% similarity in their 16S rRNA gene sequences, but were distantly related to any described members of the family Lachnospiraceae (<94%). The most closely related species with names that have standing in nomenclature were Robinsoniella peoriensis, Ruminococcus gnavus, Blautia producta and Clostridium xylanolyticum. Phylogenetic relationships based on 16S rRNA gene sequence analysis were confirmed by partial sequencing of hsp60 genes. The use of an in-house database search pipeline revealed that the new isolates are most prevalent in bovine gut samples when compared with human and mouse samples for Ruminococcus gnavus and B. producta. All three isolated strains shared similar cellular fatty acid patterns dominated by C-16:0 methyl ester. Differences in the proportions of C-12:0 methyl ester, C-14:0 methyl ester and C-18:1 cis-11 dimethyl acetal were observed when compared with phylogenetically neighbouring species. The major short-chain fatty acid produced by strain SRB-530-5-H-T was acetic acid. This strain tested positive for utilization of D-fructose, D-galacturonic acid, D-malic acid, L-alanyl L-threonine and L-glutamic acid but was negative for utilization of amygdalin, arbutin, alpha-D-glucose, 3-methyl D-glucose and salicin, in contrast to the type strain of the closest related species Robinsoniella peoriensis. The isolates were not able to use mannitol for growth. Based on genotypic, phenotypic and chemotaxonomic characteristics, we propose to create the new genus and species Murimonas intestini gen. nov., sp. nov. to accommodate the three strains SRB-530-5-H-T (=DSM 26524(T)=CCUG 63391(T)) (the type strain of Murimonas intestini), SRB-509-4-S-H (=DSM 27577=CCUG 64595) and SRB-524-4-S-H (=DSM 27578=CCUG 64594).