Glycaemic status affects the subgingival microbiome of diabetic patients

AimPeriodontitis iscorrelated with type 2 diabetes mellitus (T2DM), but little is known about glycaemic status effect on subgingival microbiota associated withperiodontitis. This study evaluated if periodontal microbiome of T2DM patients is affected by glycaemic status. Materials and methodsTwenty-one T2DM non-smoking patients with chronic periodontitis and body mass index 40kg/m(2) were allocated into two groups according to systemic glycaemic status: inadequate (DMI- HbA1c8%) and adequate (DMA- HbA1c <7.8%). Subgingival biofilm was collected from sites with moderate (PD=4-6mm) and severe disease (PD7mm) in two quadrants. The V5-V6 hypervariable region of the 16SrRNA was sequenced using the GS-FLX-454 Titanium platform. Sequences were compared with HOMD database using QIIME and PhyloToAST pipelines. Statistical comparisons were made using two-sample t-tests. ResultsDMA microbiome presented higher diversity than DMI. Inadequate glycaemic control favoured fermenting species, especially those associated with propionate/succinate production, whereas those forming butyrate/pyruvate was decreased in DMI. Higher abundances of anginosus group and Streptococcus agalactiae in DMI may indicate that subgingival sites can be reservoir of potentially invasive pathogens. Altered subgingival microbiome in DMI may represent an additional challenge in the periodontal treatment of these patients and in the prevention of more invasive infections. ConclusionGlycaemic status in T2DM patients seems to modulate subgingival biofilm composition.