The localization of periodontal-disease-associated bacteria in human periodontal pockets

Some Gram-negative anaerobes are associated with the incidence and progression of periodontal disease. In periodontal pockets, however, the localization of those bacteria is unknown. We investigated the localization of 5 bacterial species in human periodontal pockets. Fifteen teeth with a part of periodontal pockets from 10 adult periodontitis patients were obtained, and the localization of bacteria was examined immunohistochemically. Positive reactions with anti-Prevotella nigrescens antibody were located at the epithelium-associated plaque area in the middle pocket zones. In the middle and deep pocket zones, Fusobacterium nucleatum and Treponema denticola were especially localized in the unattached plaque area, but Eikenella corrodens was observed in the tooth-attached plaque area. Actinobacillus actinomycetemcomitans, detected in 2 of 15 samples examined, was found in the unattached plaque area, in the middle pocket zone. The present findings indicated that the 5 bacterial species examined localized at distinct regions in human periodontal pockets.