Rise and subsequent decline of community-associated methicillin resistant Staphylococcus aureus ST30-IVc in Copenhagen, Denmark through an effective search and destroy policy

The number of patients with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has increased rapidly in Copenhagen, Denmark since 2003. Patients with the typical Panton–Valentine leukocidin-positive CA-MRSA clone ST30-IVc were contacted with the aim of treating MRSA carriers, evaluating the effect of MRSA eradication therapy (ET), and finding links among patients. Twenty-three index patients infected with the ST30-IVc clone from November 2003 to September 2005 were contacted and transmission chains were studied. The majority of ST30-IVc patients had a connection to the Philippines. Household members were screened for MRSA and all members of families with MRSA carriers were offered treatment of the carrier state and were followed for 1 year. MRSA carriers were found in seven of 16 households and transmission occurred among close contacts and in kindergartens. Five days of ET was insufficient and at least one person in each household was treated with systemic antibiotics. All families were MRSA negative at 1-year follow-up. The CA-MRSA clone ST30-IVc has been imported to Copenhagen, Denmark, primarily from the Philippines, and has spread through close contacts and in kindergartens. Treatment of MRSA carriers was difficult and required many resources, but the clone was eventually successfully eliminated. The import of ST30-IVc to Denmark will continue, but the spread of the clone in Denmark can be kept to a minimum by direct intervention in the affected families.