Phenotypic and phylogenetic characterization of some Eubacterium-like isolates containing a novel type B wall murein from human feces: description of Holdemania filiformis gen. nov., sp. nov.

A group of Eubacterium-like strains (designated group S14), isolated from the feces of healthy people, was characterized by biochemical tests, fatty acid analysis, cell wall murein analysis, and 16S rDNA analysis. Our results indicate that group S14 is phylogenetically a member of the Clostridium subphylum of the gram-positive bacteria. Despite a phenotypic resemblance to the genus Eubacterium, group S14 was shown to be phylogenetically distantly related to the type species of the genus, Eubacterium limosum. Group S14 showed a specific phylogenetic association with Erysipelothrix rhusiopathiae. Group S14 resembled Erysipelothrix in possessing the uncommon type B cell wall murein. Structural analyses, however, revealed the presence of a previously unknown B1 delta (L-Ala)-D-Glu-Gly-L-Lys murein type. Based on a 16S rRNA sequence divergence of greater than 10% with E. rhusiopathiae and the presence of a unique murein type, a new genus, Holdemania, is proposed for group S14, with one species, Holdemania filiformis. Type strain of H. filiformis is ATCC 51649.