Characteristic Correlation between Staphylococcal Isolates from Wounds and Nares of Diabetic Foot Patients Living in Erbil City, Iraq

Introduction: Foot ulcers are a common and serious complication in patients with diabetes mellitus. Nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) may serve as a reservoir for autoinfection. This study aimed to investigate the association between S. aureus isolates obtained from nasal passages and foot infections in diabetic patients. Methods: Nasal and foot wound swabs were collected from 84 diabetic patients. Bacterial identification and antibiotic susceptibility testing were performed using the VITEK 2 system. Methicillin resistance was determined using Oxacillin Salt Agar Screen, PBP2a assays, and mecA gene detection. Genetic correlation between nasal and wound isolates was assessed by pulsed-field gel electrophoresis (PFGE). Results: S. aureus was the most prevalent isolate, accounting for 33.1% of samples. Methicillin resistance was detected in 55.1% of foot wound isolates and 73.3% of nasal isolates. The mecA gene was identified in 95.3% of both S. aureus and coagulase-negative Staphylococci. PFGE analysis showed 100% genetic homology between paired nasal and wound isolates. Discussion: The data confirmed that S. aureus is the predominant bacterium in diabetic foot lesions. Our findings also suggest that these infections in diabetic patients are likely of endogenous origin. Conclusion: Diabetic foot patients carrying S. aureus in the nares are at high risk of self-contamination. These findings highlight the need for routine nasal screening and decolonization strategies to reduce infection risk in this vulnerable population.