Methicillin-resistant Staphyloccocus aureus (MRSA) isolation from diabetic foot ulcers correlates with nasal MRSA carriage

Methicillin-resistant Staphylococcus aureus is increasingly isolated from diabetic foot ulcers, and may be associated with an adverse prognosis. We have explored the relationship between MRSA isolation from foot ulcers and nasal MRSA carriage. Over a 12 month period, 65 consecutively attending patients with diabetic foot ulceration were recruited. Demographic information was collected, and the ulcer and nose swabbed bacteriologically using standard techniques. The patients were mean age 61year, diabetes duration 14 year, and HbA1c 8.5%. There were 61% male and 85% with type 2 diabetes. Ulcers were neuropathic in 55%, ischaemic in 14% and neuroischaemic in 31%. MRSA was isolated from 12 (19%) ulcers, and 11 (17%) had nasal carriage. Of the MRSA positive ulcer patients 7/12 (58%) had nasal MRSA carriage, compared with 4/53 (8%) with MRSA negative ulcers (p<0.0003). We conclude that nasal MRSA carriage in diabetic patients is a significant risk factor for foot ulcer MRSA infection.