BIFIDOBACTERIUM INOPINATUM SP-NOV AND BIFIDOBACTERIUM-DENTICOLENS SP-NOV, 2 NEW SPECIES ISOLATED FROM HUMAN DENTAL-CARIES

In a previous investigation of bifidobacteria isolated from human dent al caries (V, Scardovi and F, Crociani, Int, J Syst, Bacteriol, 24:6-2 0, 1974), 40 strains were assigned to the new species Bifidobacterium dentium. In this study we examined 70 new strains of bifidobacteria is olated from dental caries, The morphological characteristics, biochemi cal reactions, fermentation patterns, end products from glucose metabo lism, protein electrophoretic patterns, levels of DNA hybridization, a nd DNA G+C contents of these organisms revealed that they belong to th ree different taxa, One of these taxa was identified as B, dentium. Th e other two are described as the following new Bifidobacterium species in this paper: Bifidobacterium inopinatum (type strain, DSM 10107) an d Bifidobacterium denticolens (type strain, DSM 10105), The two new sp ecies differ from other Bifidobacterium species in their morphological characteristics (especially B, inopinatum, with its very small coccoi d cells), in their carbohydrate fermentation patterns (most strains fe rment dextran, and B, inopinatum does not ferment galactose), and in t heir DNA base compositions (especially B, inopinatum).