Alteration of salivary microbiome in periodontitis with or without type-2 diabetes mellitus and metformin treatmentOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study examined the salivary microbiome to understand how type-2 diabetes mellitus (T2DM) and hypoglycemic (metformin) treatment alter oral bacterial communities in people with periodontitis. Researchers used 16S rRNA gene sequencing to profile saliva samples and identify shifts in microbial diversity and composition across disease states. They also explored whether specific salivary taxa could serve as an early biomarker for T2DM in periodontitis patients. In total, 29 phyla, 322 genera, and 333 species of salivary microbiome were annotated.
Who was studied?
The study population consisted of saliva samples from five groups: healthy individuals, periodontitis patients, T2DM patients without periodontitis, periodontitis patients with T2DM (DAP), and DAP patients treated with metformin. The abstract does not specify exact sample sizes or demographic details for each group. This comparative, multi-group design allowed the researchers to isolate the effects of periodontitis, diabetes, and metformin treatment on the oral microbiome.
What were the most important findings?
Periodontitis patients, with or without T2DM, showed significantly higher salivary microbial diversity than healthy individuals, while T2DM and metformin-treated groups showed no significant difference in abundance but a trend toward increasing diversity. Beyond well-known periodontitis-associated pathogens, Prevotella copri, Alloprevotella rava, and Ralstonia pickettii were significantly increased in periodontitis patients regardless of diabetes status. After effective glycemic control with metformin, the abundance of these taxa, including Prevotella copri, Alloprevotella rava, and Ralstonia pickettii, decreased in periodontitis patients with concurrent T2DM. Classification models were built to differentiate health, periodontitis, and diabetes-related groups based on these microbial signatures.
What are the greatest implications of this study?
The findings suggest that specific salivary taxa such as Prevotella copri, Alloprevotella rava, and Ralstonia pickettii could serve as microbial indicators linking periodontitis and glycemic status. Because these taxa decreased after effective glycemic control, they may have potential as early warning biomarkers for T2DM in periodontitis patients. This points toward saliva-based microbiome monitoring as a noninvasive tool for tracking metabolic-periodontal interactions and treatment response. Further validation could support integrating salivary microbiome profiling into diabetes and periodontal disease management.