FIG. 1.

Phylogenetic tree derived from partial 16S rDNA sequence data for members of the Bacteroides group. Bar represents 2% sequence divergence. Designations of clones and key organisms used to name the subgroups are in boldface type. The tree was constructed with the SIMILARITY and NEIGHBOR programs. Bootstrap values are based on 500 replications. Vertical bars correspond to the Anaeroflexus assemblage (a) Bacteroides fragilis subgroup (b), Prevotella subgroup (c), and Bacteroides distasonis subgroup (d).