Black-pigmented, asaccharolytic Bacteroides species resembling Porphyromonas gingivalis (Bacteroides gingivalis) from beagle dogs.

Black-pigmented, asaccharolytic Bacteroides strains, which positively reacted with anti-Bacteroides gingivalis (now reclassified as Porphyromonas gingivalis) serum, were isolated from beagle dogs, and their characteristics were studied and compared with those of P. gingivalis. The strains from dogs were different from P. gingivalis in their catalase activity, nutritional requirements and oxygen tolerance, and double-immunodiffusion tests showed serological dissimilarity between the strains from dogs and P. gingivalis. However, the strains from dogs had guanine-plus-cytosine contents of 49.0 to 49.3 mol %, which were very similar to P. gingivalis, and they showed strong DNA-DNA hybridization with P. gingivalis. These results indicated that beagle dogs had Porphyromonas species analogous to P. gingivalis in their oral cavities.