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MOLECULAR ANALYSIS OF BACTERIA ASSOCIATED WITH CHRONIC PERIODONTITIS AND PERIODONTAL HEALTH

Purnima Kumar
11/30/2013

Chronic periodontitis is a disease of tooth-supporting tissues, affecting over half the population in the United States. The etiological role of bacteria is established, although contributions of individual species or groups of organisms are unclear. Molecular analysis of the plaque biofilm allows study of associations between health status and cultivated and uncultivated species. The purpose of the present investigation was to identify potential periodontal pathogens and beneficial bacteria using cultivation independent approaches. Plaque from deep and shallow sites of subjects with chronic periodontitis and age-matched healthy controls was studied using quantitative 16S clonal analysis. Several species and phylotypes of Peptostreptococcus, Filifactor, Megasphaera, Campylobacter, Selenomonas, Deferribacteres, Dialister, Tannerella, Streptococcus, Atopobium, Eubacterium, Treponema and Desulfobulbus were associated with periodontitis while Streptococcus,Veillonella, Campylobacter, Abiotrophia, Gemella, Capnocytophaga and Neisseria were associated with health. The stability of bacterial colonization in the subgingival crevice was examined using a similar approach. Subjects were either periodontally healthy over two years or demonstrated improvement or worsening of their periodontal status. The microbial stability of the stable group was significantly higher than that of the group demonstrating clinical change. Veillonella oral clone X042 and uncultivated streptococci,were associated with health, while F.alocis, uncultivated treponemes and selenomonads were significantly associated with disease. This suggests that periodontal health is associated with a stable health compatible bacterial colonization and that change in clinical health is associated with a microbial shift. The prevalence of candidate species detected using the above approaches was studied in subgingival plaque from 66 subjects with periodontitis and 66 healthy controls. Species-specific ribosomal 16S primers for PCR amplification were developed for detection of 90 species. Deferribacteres clones D084/BH017, Bacteroidetes clone AU126, Megasphaera clone BB166, OP11 clone X112, and TM7clone IO25, E.saphenum, P.endodontalis, P.denticola, and C.curtum were associated with disease. Deferribacteres clone W090, Bacteroidetes clone BU063, A.rimae and A.parvulum were associated with health. In conclusion, the bacterial profile of health and disease contains large numbers of uncultivated bacteria. Robust associations are between between periodontitis and F.alocis, members of Deferribacteres, Megasphaera, Desulfobulbus, Campylobacter and Peptostreptococcus. Veillonella oral clone X042, Bacteroidetes clone BU063, streptococci and Campylobacter gracilis are associated with health.