Non-suppurative cellulitis: risk factors and its association with Staphylococcus aureus colonization in an area of endemic community-associated methicillin-resistant S. aureus infections

Suppurative methicillin-resistant Staphylococcus aureus (MRSA) skin infections are common and associated with MRSA colonization, but little is known about non-suppurative cellulitis and its relationship with MRSA colonization in areas endemic for community-associated MRSA. We prospectively enrolled patients hospitalized for non-suppurative cellulitis (n = 50) and matched controls (n = 100) and found S. aureus colonization was similar in cases and controls (30% vs. 25%, P = 0·95). MRSA was uncommon in cases (6%) and controls (3%) (P = 0·39). All MRSA isolates were USA300 by pulsed-field gel electrophoresis. Independent risk factors for non-suppurative cellulitis were diabetes (OR 3·5, 95% CI 1·4–8·9, P = 0·01) and homelessness in the previous year (OR 6·4, 95% CI 1·9–20·9, P = 0·002). These findings suggest that MRSA may only rarely be causative of non-suppurative cellulitis.