National Danish case-control study of community onset infections caused by methicillin-resistant Staphylococcus aureus

Abstract number: o313

Böcher  S., Gervelmeyer  A., Monnet  D.L., Mølbak  K., Skov  R.


Denmark has for more than 25 years been a low prevalence country for MRSA (< 1percnt;). However, during the last 3 years a significant rise in MRSA infections especially with community onset (CO-MRSA) has been observed. In order to characterise patients with staphylococcal infections and to identify possible risk factors for CO-MRSA infection we conducted a nationwide case-control study.


During 2004 patients with community onset MRSA in Denmark were identified; controls were selected from a random sample of patients with community onset methicillin sensitive S. aureus (MSSA). After informed consent the patients were interviewed by telephone regarding type of infection, previous antibiotic treatment, chronic illnesses, household infections, hospitalisation, or contact to health care or other institutions, travel abroad, sports and occupation. The general practitioners of the patients received a questionnaire regarding clinical signs, localisation of infection and chronic illnesses.


99 CO-MRSA patients were identified, 37 had both GP and patient questionnaires completed. 330 MSSA controls were identified by the laboratories, 84 of these had both questionnaires completed. Skin and soft tissue infections were the predominant manifestation in both cases (68%) and controls (60%). A large proportion of cases (27%) and controls (38%) had underlying skin disease. Skin lesions prior to infection was associated with a reduced risk of MRSA (OR: 0.2, 95% CI 0.1–0.7). Most cases (69%) and controls (59%) had received antibiotics within the last 6 months and 47% resp. 30% had been hospitalized within the last year. More MRSA patients had been hospitalised for > 7 days (OR 4.1, 95% CI 1.2–14.3). Foreign ethnicity was associated with an increased risk of MRSA (OR 19.1, 95% CI 2.2–872.3).


Prior hospitalization within the last year of > 7 days and other ethnicity than Danish was found to be significant risk factors for CO-MRSA infections. CO-MRSA infections were dominated by skin and soft tissue infections and the majority of MRSA patients had received antibiotics within the last 6 months. The apparent protective effect of skin lesions is not yet fully understood.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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