Investigation and quantification of key periodontal pathogens in patients with type 2 diabetes

Diabetes is a recognized risk factor for periodontitis. There are conflicting data regarding whether healthy diabetic patients or diabetic patients with chronic periodontitis have an altered subgingival microbiota compared with nondiabetic individuals. The aim of the present study was to detect quantitative differences in selected periodontopathogens in the subgingival plaque of diabetic patients using TaqMan quantitative PCR.

Type 2 diabetes mellitus patients with (n=9) or without chronic periodontal disease (n=15) were recruited and matched to nondiabetic control subjects (n=12 periodontally healthy, n=12 chronic periodontitis). Subgingival plaque samples were collected from deep (>4 mm probing depth) and shallow sites (≤3 mm probing depth) using paper points, and Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Porphyromonas gingivalis were quantified.

Forty-eight subjects (69 samples) were recruited. Marked differences were seen in the levels of all three bacterial species, relative to the total bacterial population, according to periodontal health status. Using real-time quantitative PCR, bacterial counts for P. gingivalis were significantly higher in deep pockets of diabetic and nondiabetic subjects compared with periodontally healthy subjects (p<0.05) but did not differ significantly between diabetics and nondiabetics. A. actinomycetemcomitans was detected in all groups in low quantities, and counts did not differ significantly between groups (p>0.05). F. nucleatum was abundant in all groups, with no clear significant differences between groups. P. gingivalis was found in higher quantities in periodontitis than in periodontally healthy subjects (p<0.05). Statistically significant positive correlations were identified between pocket depth and counts for all three species tested (p<0.05).

A. actinomycetemcomitans, F. nucleatum and P. gingivalis were present in significantly different quantities and proportions in subgingival plaque, according to periodontal disease status. No significant differences were identified between the subgingival microbiota of type 2 diabetes mellitus patients compared with nondiabetic subjects.