Method: Patients enrolled in a study investigating the effect of diabetes on oral health were split into better controlled and poorly controlled groups based on a median HbA1c of 8.5%. They were examined for carriage of oral staphylococci by undertaking an oral rinse. Specimens were spiral plated and plated onto selective and non-selective agar. Presumptive S. aureus were identified by Gram stain, DNase and coagulase tests. Antimicrobial susceptibility testing was also undertaken.
Results: There was a significantly higher carriage rate of S. aureus in poorly controlled diabetics (40/88; 45%) compared to better controlled diabetics (24/83; 29%) and controls (31/101; 31%). In patients colonized by S. aureus the better controlled diabetics had a significantly lower density of colonization (mean 914 cfu/ml) compared to 5,474 cfu/ml for poorly controlled diabetics and 5,301 cfu/ml in non-diabetic controls.
Conclusion: Poorly controlled diabetics have a higher carriage rate and higher density of colonization of S. aureus in the oral cavity compared to better controlled diabetics. The role of oral S. aureus in oral disease in poorly controlled diabetics requires further prospective studies. Oral carriage of S. aureus in this patient cohort may serve as a reservoir for S. aureus infections at other body sites.
This clinical arm of this study was funded by a grant from the Chief Scientist Office, Scottish Government Health Directorates