[Community-acquired methicillin-resistant Staphylococcus aureus in a dermatology outpatient clinic]

Community-acquired cutaneous infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a growing concern. These bacteria may produce Panton-Valentine leucocidin potentially leading to necrotizing pneumonia. We studied the prevalence of MRSA and Panton-Valentine leucocidin in dermatology clinic outpatients in order to adapt therapy where possible.

This was a prospective study including all patients seen at a dermatology outpatient clinic between 1st March 2005 and 31st December 2006 and presenting mucocutaneous bacteriological samples. The main MRSA risk factors studied were frequent hospital consultations, hospitalization, antibiotic therapy within the last three months and community life. The following risk factors were also analysed, although less routinely: substance abuse, immunosuppression, diabetes mellitus, recent travel abroad and a history of similar lesions.

One hundred and twenty-two patients were included in the study and 235 samples (143 lesion samples and 92 nasal swabs) were carried out and S. aureus was isolated in 68 patients (56%). Twelve patients had MRSA (17.6%); seven of these were normal outpatients but five attended frequent hospital consultations (7.3%). MRSA resistance rates were as follows: 64% to ofloxacin, 36% to amikacin and erythromycin, 27% to fusidic acid, 9.1% to sulfamethoxazole-trimethoprim and 0% to pristinamycin. Community life was the only significant risk factor for MRSA in this study (p=0.045). Four of the 11 MRSA strains tested produced Panton-Valentine leucocidin.

Dermatologists are increasingly faced with cutaneous infections caused by community-acquired MRSA. Bacterial samples should be taken routinely and probabilistic antibiotic therapy for MRSA instituted in severe infections.