PHYLOGENY OF ORAL ASACCHAROLYTIC EUBACTERIUM SPECIES DETERMINED BY 16S RIBOSOMAL DNA-SEQUENCE COMPARISON AND PROPOSAL OF EUBACTERIUM-INFIRMUM SP-NOV AND EUBACTERIUM-TARDUM SP-NOV

16S rRNA gene sequences of Eubacterium brachy, Eubacterium nodatum, Eu bacterium saphenum, Eubacterium timidum, and two previously unnamed ta xa were determined, The results of a phylogenetic analysis indicated t hat all of the strains sequenced belonged to a deep branch of the low- G + C-content gram-positive group, The levels of 16S ribosomal DNA seq uence similarity between species were low, suggesting that a number of genera may be represented in this group, The representatives of the t wo unnamed taxa, which were isolated from patients with periodontitis, were clearly distinct from the previously described species, and, the refore, the following two new species are proposed: Eubacterium infirm um (type strain, NCTC 12940) and Eubacterium tardum (type strain, NCTC 12941).