New Candidate Pathogens in Subjects With Periodontitis

Objectives: There is extensive evidence supporting the role of certain oral bacteria species in the onset and progression of periodontitis. Nevertheless, in recent years, some new species/phylotypes have been correlated with the presence of these infections. A recent systematic review provides further support for the existence of 17 new candidate periodontal pathogens, but the actual role of these taxa in the etiology of periodontitis would depend on larger association studies. Thus, the aim of this study was to assess the prevalence and levels of these new candidate pathogens in subjects with chronic periodontitis (ChP, n=30), aggressive periodontitis (AgP, n=30) and periodontal heath (PH, n=30).
Methods: Nine subgingival plaque samples were collected from each subject and analyzed for their content of 20 bacterial species/phylotypes using the RNA-oligonucleotide quantification technique.
Results: Subjects with ChP and AgP showed higher mean levels of Bacteroidetes sp. human oral taxon (HOT) 274, Fretibacterium sp. HOT 360 and TM7 sp. HOT 356 phylotypes, Filifactor alocis, Fretibacterium fastidiuosum, Porphyromonas gingivalis, Tannerella forsythia and Selenomonas sputigena species than PH subjects (p<0.05). AgP subjects presented higher mean levels of TM7 sp HOT 356 and F. alocis than ChP subjects (p<0.05). A higher mean prevalence of Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360 and Fretibacterium sp. HOT 362 was found in subjects with GChP and AgP, than in PH subjects (p<0.01). Mean levels of P. gingivalis (r=0.68), T. forsythia (r=0.62), F. alocis (r=0.51, p=0.001) and Fretibacterium sp. HOT 360 (r=0.41) were correlated with pocket depth (p<0.001).
Conclusions: In conclusion, Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360, Fretibacterium sp. HOT 362, TM7 sp. HOT 356 phylotypes, F. alocis, F. fastidiosum and S. sputigena seem to be associated with periodontitis, and their role in periodontal pathogenesis should be further investigated.