Dysbiosis of Gut Microbiota in Japanese Patients with Periodontitis

Objectives: Accumulating evidence suggest that there is a link between gut dysbiosis and various systemic diseases that are also associated with periodontal disease. This let us speculate that gut microbiome of periodontitis patients could be different from that of healthy subjects. The aim of present study is to analyze salivary and gut microbiome of periodontitis patients and compare those with healthy subjects.
Methods: Subjects with or without moderate to severe periodontitis (N=10 each) who are otherwise healthy were included. Saliva and feces were obtained at baseline and after the initial periodontal treatment from the patients and once from control subjects during the study period. After DNA extraction, the V1-V2 regions of the 16S rRNA genes were amplified, sequenced (Illumina MiSeq), and analyzed. OTU, defined at 96% similarity, was assigned a taxonomy based on the CORE database.
Results: Among the all OTUs obtained, 260 were taxonomically assigned and the rest were unidentified. In the salivary microbiota, α-diversity was significantly higher in the samples of patients before treatment compared with controls. Unweighted UniFrac distance revealed significant qualitative differences between the two groups and within the periodontitis patients before and after treatment. In the fecal microbiota, bacterial diversity was not different between groups at baseline and within the group before and after treatment. However, unweighted and weighted UniFrac distance uncovered significant difference of gut microbiota between periodontitis patients and control subjects both qualitatively and quantitatively. Although several OTUs significantly decreased after periodontal treatment, overall composition did not change.
Conclusions: These results suggest; (1) dysbiotic gut microbiota could be a risk factor for periodontal disease, (2) oral microbiome has some influence on the gut microbiome.