Meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia in Tampere University Hospital: a case-control study, Finland October 2002 to January 2010

Meticillin-resistant Staphylococcus aureus (MRSA) has emerged as a frequent pathogen in blood cultures in Pirkanmaa Hospital District (HD), Finland. To study risk factors for MRSA bacteraemia and the adequacy of empirical antimicrobial treatment, we retrospectively reviewed the hospital records of 102 patients, 51 with MRSA, and 51 with meticillin-sensitive Staphylococcus aureus (MSSA) bacteraemias respectively, who had been admitted to Tampere University Hospital in Pirkanmaa HD, from October 2002 to January 2010. For each patient with MRSA bacteraemia, one consecutively detected unmatched patient with MSSA bacteraemia was chosen as control. Patients with MRSA bacteraemias were significantly older (median age: 73 years vs 59 years, p=0.001), were more likely to have been transferred directly from another healthcare facility or were already in the hospital at the onset of bacteraemia (39/51 vs 26/51, p=0.007) and had a higher McCabe class than patients with MSSA bacteraemia (p=0.005). Patients with MRSA bacteraemia more seldom received adequate empirical antimicrobial therapy when compared to those with MSSA bacteraemia (13/51 vs 43/51, p<0.001). Of previously known MRSA carriers 10 of 29 received adequate empirical antimicrobial therapy for their condition. The percentage of MRSA bacteraemias among all S. aureus bacteraemias in Pirkanmaa HD is high compared to corresponding figures for the whole of Finland.