Bifidobacterium Species Expressing Phenotypical Similarity to Bifidobacterium adolescentis Isolated from the Feces of Human Adults

Abstract

Seventy-six strains of Bifidobacterium adolescentis and phenotypically similar Bifidobacterium species, of which 56 strains were isolated from the feces of human adults in our laboratory and 20 strains were obtained from DSM and ATCC as type strains or reference strains, were studied by carbohydrate fermentation patterns, DNA base compositions and DNA/DNA homologies. On the basis of DNA/DNA homology they were divided into six species: B. adolescentis, B. pseudocatenulatum, B. catenulatum, B. angulatum, B. dentium and B. longum. The strains of B. angulatum and B. dentium were not detected in 56 strains isolated from the feces of human adults. B. catenulatum could be distinguished from other four species, except for B. longum, by the inability to ferment glycogen and mannose. The G+C contents of DNAs of B. pseudocatenulatum and B. catenulatum (57.1•}0.7 mol% and 56.5•}1.0 mol%, respectively) were lower than that of B. adolescentis (59.8•}0.9 mol%). It was difficult to differentiate B. adolescentis biovar b and B. dentium, and B. adolescentis biovar c and B. pseudocatenulatum on the basis of carbohydrate fermentation pattern.