Abstract |
Comparison of 16S rRNA sequences showed that strains classified as Bacteroides succinogenes are not closely related to other species of Bacteroides, including the type species Bacteroides fragilis. Therefore, the study proposes that B. succinogenes strains be renamed as members of a new genus, Fibrobacter. Based on the 16S rRNA sequence divergence between two subgroups within that genus, two species have been formed. Isolates from the rumen are placed in F. succinogenes; the neotype strain is S85 (ATCC 19169). Isolates from the ceca of nonruminant animals are placed in F. intestinalis; the type strain is NR9 (ATCC 43854). Members of F. succinogenes can be differentiated from F. intestinalis by their requirement for biotin; the site of isolation may not be diagnostic. Fibrobacter succinogenes consists of two subspecies; subsp. succinogenes strains are broad rods, often pleimorphic and coccoid, whereas cells of subsp. elongata are slender rods. (Copyright (c) 1988, International Union of Microbiological Societies.) |