Identification of Bacteroides species from adult periodontal disease

Samples from deep (4-7 mm) periodontal pockets were collected from 17 patients with adult-type periodontal disease and one with the juvenile form of the disease. They were streaked immediately on selective and non-selective media and incubated anaerobically for 96 h. There was a heavy growth of Bacteroides spp. from most samples and 10 representative colonies from each sample were sub-cultured for identification. In a total of 149 isolates from patients with adult-type disease, the commonest species were B. oralis (40), B. asaccharolyticus (35), B. intermedius (31), B. fragilis (12) and B. ureolyticus (10); B. gingivalis was not detected. The distribution of species was not distorted by multiple identical isolates from individual patients. There was a heavy growth of a single species, B. ureolyticus, from the patient with juvenile-type disease.