Methicillin-Resistant Staphylococcus aureus Infections in Uppsala County, Sweden

Abstract

The epidemiology of community-acquired (CA) and health care-associated (HCA) Methicillin-resistant Staphylococcus aureus (MRSA) infections were investigated in a prospective 3-year (2004-2006) surveillance study in Uppsala County. MRSA was isolated from all patients with soft tissue lesions attending hospitals and primary care clinics, as well as by systematic screening, regardless of symptoms, from all patients seeking medical care who had been treated abroad. Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and spa typing were performed. The Panton-Valentine leukocidin (PVL) gene and resistance profiles were recognised. The cost of bacterial analysis was calculated. During the surveillance period, isolates were collected from 7 967 individuals of whom 82 were colonised or infected with MRSA.

(24 HCA and 58 CA). A majority (65%) of the MRSA isolates originating outside Sweden. The isolates could be assigned into nine well-known international clones. The most frequent clone was CC8 (32%) within four clusters were identified and equally distributed between HCA and CA-isolates. The next most frequent clone was CC80 (DK E97-1) (23%) only discovered in CA isolates. Resistance to antibiotics other than β-lactams was found in 25% of the domestic isolates and in 60 % of isolates originating abroad. None of the HCA isolates carried the virulence determinant PVL gene. There was no spread of MRSA in the community or in hospitals during the surveillance period. Most domestic cases had certain risk factors. Travellers from or family relatives in the Middle East or Asia were highly overrepresented. To save costs selected screening is recommended.