Impact of systemic antibiotics on the subgingival microbiome of patients undergoing non-surgical treatment of severe periodontitis

Given a randomized controlled trial of patients with both severe periodontitis and peripheral artery disease, this report characterizes microbial shifts over 12 months following non-surgical periodontal treatment with or without adjunctive antibiotics. Materials and methods: After randomizing 90 patients to full-mouth mechanical debridement with or without adjunctive systemic antibiotics (PT1 and PT2 groups) or no subgingival debridement (control group), periodontal probing depths were measured and subgingival plaque samples obtained at baseline and during the 3-month and 12-month follow-up visits. Next-generation 16S DNA sequencing was used to characterize the microbiota of the samples for alpha/beta diversity and differentially abundant taxa. Results: Complete data was available for 76 patients. At 3 months, shallow (=3.4 mm) or advanced (=5.5 mm) pockets were significantly more, or less, prevalent in the PT1 than the control group (p=.013/.004). Microbiologically, the PT1 group was even more distinct, being associated with statistically significant changes over time (in alpha/beta diversity and differential taxa abundances) not seen in the PT2 and control groups. Conclusions: This study indicates that, although non-surgical treatment can reduce periodontal inflammation with or without antibiotics, subgingival microbial diversity can only be sustainably affected, and the proportion of periodontitis-associated microbiota reduced, in the presence of adjunctive systemic antibiotics.