Antibiotic Resistance Genes in Periodontitis

Antimicrobial resistance (AMR) is a major global public health concern, and the oral microbiome may serve as an important reservoir of antibiotic resistance genes (ARGs). Periodontitis is a chronic inflammatory disease characterized by dysbiosis of the subgingival microbiome and progressive destruction of tooth-supporting tissues. The complex microbial communities within subgingival biofilms may facilitate the exchange of ARGs through horizontal gene transfer (HGT), potentially contributing to the dissemination of antimicrobial resistance. This observational study aims to comparatively investigate the microbial composition, antibiotic resistance gene profiles, and associated mobile genetic elements (MGEs) in the subgingival microbiomes of periodontally healthy individuals and patients with periodontitis using shotgun metagenomic sequencing. Subgingival plaque samples will be collected from 50 participants, including 25 periodontally healthy individuals and 25 patients diagnosed with periodontitis, attending Istanbul University Faculty of Dentistry. Following microbial DNA extraction, shotgun metagenomic sequencing will be performed to characterize the taxonomic and functional composition of the subgingival microbiome. Bioinformatic analyses will be conducted using established databases and tools, including CARD, RGI, ARGs-OAP, MobileElementFinder, PlasmidFinder, ICEberg, and ISfinder, to identify ARGs, characterize MGEs, and investigate their potential associations. The study will compare the diversity, abundance, and distribution of ARGs and MGEs between the two groups and assess the potential relationship between periodontal dysbiosis and the genetic capacity for horizontal transfer of antibiotic resistance. By providing a comprehensive characterization of the subgingival resistome and its associated mobile genetic elements, this study aims to improve understanding of the potential contribution of periodontal disease to antimicrobial resistance and provide scientific evidence supporting the rational use of antibiotics in periodontal care.

Inclusion Criteria: * Adults aged 18-65 years. * Systemically healthy individuals. * Non-smokers. * No antibiotic use within the previous 6 months. * No periodontal treatment within the previous 6 months. * Willingness to participate and provide written informed consent. * For the periodontally healthy group: full-mouth bleeding on probing score \