Nuevo modelo de patogenia de la periodontitis crónica: de la enfermedad infecciosa a la disbiosis polimicrobiana

Abstract

Aim:to analyze the subgingival microbiota associated with chronic periodontitis by pyrosequencing of 16 S rRNA gene. Material and methods:the study group consisted of 50 patients, 20 with periodontal health (Control) and 30 with generalized chronic periodontitis (Perio). Patients subgingival samples were obtained by autoclaved paper points, DNA from which was analyzed by pyrosequencing of PCR products of 16 S rRNA gene. Bacterial diversity was determined by rarefaction curves, diversity indexes and principal coordinates analysis. The taxonomic assignment of sequences obtained was performed with the "Ribosomal Database Project classifier". Results: in the total samples analyzed, 94 bacterial genera and 202 bacterial species (from 41 genera of interest) were identified. Rarefaction curves and indexes showed a greater number of species in the samples of Perio group. In the Perio group were obtained significantly higher abundance percentages for Porphyromonas, Tannerella, Treponema, Filifactor, Peptostreptococcus, Eubacterium, Desulfobulbus, Hallella, Bulleidia, Phocaeicola and Mogibacterium; and significantly lower percentages for Fusobacterium, Streptococcus, Leptotrichia, Capnocytophaga, Corynebacterium,Veillonella, Neisseria, ActinomycesandJohnsonella. Significant differences were detected in the percentage of 30 bacterial species abundance between both study groups. There were 14 genera and 25 bacterial species which showed significant correlations with clinical parameters associated with periodontal status (probing depth, clinical attachment loss and/or bleeding on probing). Conclusions:pyrosequencing 16 S rRNA gene revealed greater diversity and different structure-composition of the subgingival microbiota in chronic periodontitis. Periodontopathic organisms were found at low proportions in healthy individuals, supporting that this pathology cannot be considered an infectious disease in classical terms. On the contrary, the disease is associated with polymicrobial dysbiosis, which is characterized not only by greater involvement of "established" pathobionts, but also by the coexistence of other pathobionts of unknown role, such as Filifactor alocis.