Skin infections caused by community-acquired methicillin-resistant Staphylococcus aureus: clinical and microbiological characteristics of 11 cases

Introduction: Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging pathogen that causes skin and soft-tissue infections.

Objective: To describe the clinical characteristics of skin infections caused by CA-MRSA and correlations with the available demographic and microbiological data.

Material and methods: This was a descriptive study of patients with a microbiologically confirmed diagnosis of CA-MRSA infection treated in a dermatology department between June 2009 and December 2011. We recorded demographic details, the clinical characteristics of lesions, and the treatments used.

Results: We studied 11 patients (5 men and 6 women); 91% were under 40 years of age and had no relevant past medical history. The most common presentation was a skin abscess (with or without cellulitis). In all such cases, marked tissue necrosis and little or no purulent exudate was observed when the abscess was drained. Fifty percent of these abscesses had been treated previously with β-lactam antibiotics, and in all cases the lesions resolved after surgical drainage, which was combined in 63% of cases with quinolones or cotrimoxazole.

Conclusions: Today, skin infections due to CA-MRSA affect healthy young athletes who have no contact with healthcare settings. The most common presentation is a skin abscess characterized by marked tissue necrosis and little or no purulent exudate. In cases with these characteristics in susceptible patients, the involvement of CA-MRSA as the causative agent should be suspected. The abscesses should be drained whenever possible and, if necessary, antibiotic treatment should be prescribed; empirical use of β-lactam antibiotics should be avoided.