Nasal Carriage of Methicillin-Resistant Staphylococcus aureus in Prediabetes and Type 2 Diabetes Mellitus

Aim: Staphylococcus aureus (S. aureus) nasal colonization, especially with methicillin-resistant S. aureus (MRSA), is a significant risk factor for infection and transmission. While diabetes mellitus (DM) is a recognized risk factor, its association with prediabetes (preDM) is less apparent. This study investigated MRSA nasal carriage in DM and preDM and its relation to metabolic and anthropometric parameters.Material and Methods: This cross-sectional study included 300 participants: 100 with type 2 DM, 100 with preDM and 100 non-diabetic controls attending General Internal Medicine clinics (May–August 2025). PreDM and DM were defined by American Diabetes Association (ADA) criteria and individuals with recent antibiotic use, acute infection, immunosuppression, dialysis or malignancy were excluded. Nasal swabs were cultured on blood agar, identified by MALDI-TOF and tested for methicillin resistance using oxacillin MIC per Clinical and Laboratory Standards Institute (CLSI M100 35th ed., 2025) standards. Clinical and laboratory parameters were assessed using nonparametric statistical tests, with significance set at p < 0.05.Results: MRSA nasal carriage was higher in DM patients than controls (8% vs 1%, p=0.035). DM was associated with greater waist circumference and poorer glycemic profiles. MRSA carriage showed weak positive correlations with body weight, fasting glucose, HbA1c and triglycerides, and a weak negative correlation with albumin. Prediabetes showed a nonsignificant increase compared with controls.Conclusion: Type 2 DM was associated with increased MRSA nasal carriage, whereas prediabetes was not; intermediate rates in prediabetes do not support routine MRSA screening in this group. These findings support a selective, risk-based approach rather than routine MRSA screening in prediabetic populations.