Aspects épidémiologiques de Staphylococcus aureus résistant à la méticilline dans un centre hospitalier de taille moyenne

Abstract

Objective – The aim of this study was to assess the incidence of colonization/infection by methicillin-resistant Staphylococcus aureus (MRSA) in our hospital. Method – For two months, cases of MRSA colonization or infection were monitored prospectively. Antibiotic susceptibility patterns and molecular methods were used to type the isolated strains. Morbidity was determined from the incidence of patients colonized/infected by MRSA, according to the type of ward. Results – The overall incidence of patients colonized/infected by MRSA was 1.22%. Incidence depended on the type of ward; it was 1.56 per thousand days of hospitalization in short-term care wards, and 1.65 per thousand days of hospitalization in long-term care wards. MRSA skin colonization or wound infection was most frequently observed (53.1%). Chromosomal DNA macro restriction analysis, with SmaI by pulsed-field gel electrophoresis, revealed that some epidemic MRSA clones were widespread. Most of the 32 MRSA isolates (78.2%) were closely related, and among these strains, 96% displayed the same antibiotype. Community-acquired MRSA accounted for 25% of the MRSA colonization/infection cases. Nevertheless, when considering significant factors of persistent carriage, true community-acquired MRSA cases only accounted for 6.25% of all cases. Conclusion – Computer-triggered warnings in the patient's file, might contribute to the early detection of previously colonized or infected patients readmitted to the hospital.