Community-acquired methicillin-resistant Staphylococcus aureus in Switzerland: first surveillance report.

Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging community pathogen. Community-acquired MRSA (CA-MRSA) has been associated with virulent strains producing Panton-Valentine leukocidin (PVL) and a variety of other exotoxins. In Geneva, PVL-producing CA-MRSA was first reported in 2002 and a surveillance system based on voluntary reporting was set up. Each MRSA-positive culture result with an antibiotic resistance profile different from the endemic strain prevailing in the Geneva healthcare setting diagnosed in a patient without a history of hospital admission in the previous 12 months was notified to the local health department. A questionnaire was completed by the attending physician with demographic, clinical and exposure information. From January 2002 until December 2004, data on 58 cases were reported, including 26 cases grouped in 13 distinct transmission clusters. Most were family related and for two of them, colonisation persisted over a 12 month period despite treatment. Thirty three patients (57%) were male. Median age was 32 years, 22% being younger than 10 years. Forty one cases (71%) were infected and 17 (29%) colonised. Symptomatic skin lesions such as furunculosis, impetigo or abscess were present in 40 (97%) of the 41 infected cases. Most cases had no underlying disease. Thirty eight cases (65%) had travelled abroad. Forty (69%) of 58 isolates carried the PVL toxin. CA-MRSA infections in Geneva appear to be an emerging problem in the canton. Surveillance should continue and should possibly be extended to other parts of the country to better describe transmission patterns and the spread of this pathogen. Prevention and control of CA-MRSA infections represent a challenge for the future, requiring contact tracing, education and treatment of infected and colonised contacts.