Spread of a methicillin-resistant Staphylococcus aureus ST80-IV clone in a Danish community

OBJECTIVE: We report a community cluster of methicillin-resistant Staphylococcus aureus (MRSA) in Denmark with emphasis on routes of transmission and infection control measures. The objective is to extend knowledge of MRSA in a community setting where a nosocomial link could effectively be ruled out. DESIGN: Population-based observational study from November 1997 until June 2003. SETTING: North Jutland County, with approximately 495,000 inhabitants. SUBJECTS: The cluster encompassed 46 individuals and 26 households. INTERVENTIONS: Infection control measures included repeated visits to affected households by an infection control nurse who undertook screening for carriage among all household members and provided a program for decolonization. RESULTS: The causal strain was identical to a newly described international clone, ST80; SSCmec type IV; and Panton-Valentine leukocidin positive. Plausible routes of transmission included household contact and contact at work, kindergarten, and school. We did not detect a nosocomial source or any secondary cases in hospitals. Transmission by healthcare contact outside the hospital was plausible for three cases. We found evidence that the clone was introduced on more than one occasion to immigrant families from the Middle East. A 5-day decolonization program was successful at first attempt in 15 of 16 households that could be evaluated. CONCLUSIONS: Despite the described infection control measures, we continued to see new cases, underlining a need for a national policy to contain MRSA in the community.