Abstract
BACKGROUND/PURPOSE: Adjunctive use of systemic antibiotics has more clinical improvement than scaling and root planing alone in stage III-IV periodontitis patients with type 2 diabetes mellitus (T2DM). There is still no study that concentrate on dynamic changes in oral microbiota by high throughput sequencing technique with the treatment regimen including adjunctive antibiotics. MATERIALS AND METHODS: Thirty-two periodontitis patients with T2DM who received non-surgical periodontal treatment (NSPT) in the previously published randomized trial were selected for microbiological analysis. Seventeen subjects in the test group received scaling and root planing (SRP) and antibiotics (500 mg of amoxicillin [AMX], and 200 mg of metronidazole [MTZ], three times daily for seven days). Fifteen subjects in the control group received SRP only. Examination of periodontal and hematological parameters, cytokines in serum and gingival crevicular fluid, and collection of subgingival plaque was taken at baseline and three months after treatment. The V3-V4 region of 16S DNA was sequenced, and taxonomic assignment was based on the Human Oral Microbiome database. RESULTS: Both the test and the control group showed lower richness and diversity for subgingival microbiota after treatment. The distribution of subgingival microbial composition was different between the baseline and 3 months in both groups. The subgingival microbial dysbiosis index decreased significantly in both groups at 3 months, and 8 out of 12 dysbiotic discriminatory genera decreased significantly in the test group. The relative abundance of the red complex, Porphyromonas gingivalis and T. forsythus decreased more in the test group than that in the control group. The decrease of clinical periodontal parameters was positively correlated with the decline of Treponema, Porphyromonas, Capnocytophaga and PeptostreptococcaceaeXIG-6, and negatively correlated with the increase of Neisseria and Pseudomonas. HbA1c level decrease was positively related to the changes of Leptotrichia, Veillonella, Saccharibacteria TM7 G-5 and Actinomyces. CONCLUSION: NSPT could significantly change the oral microbiome towards healthy status in patients with stage III-IV periodontitis and diabetes. AMX + MTZ had more advantages in the decrease of periodontal pathogens. Periodontists should cautiously use the antibiotics to treat such patients.