Prospective multicenter study of Staphylococcus aureus bacteremia -: results from the "Invasive Staphylococcus aureus Infection Cohort" (INSTINCT) study

Objective: Staphylococcus aureus is a leading cause of bloodstream infection and S. aureus bacteremia (SAB) is one of the most severe infections acquired in hospital or in the community. The epidemiology and prognosis of this infection in Germany is not fully understood because of the lack of prospective data. Methods: A prospective, multicenter cohort study (INSTINCT, Invasive Staphylococcus aureus Infection Cohort) was initiated to record and analyse data on patients with SAB through an internet-based documentation. Data are being obtained by specially trained personnel. Clinical variables recorded are comorbidities, risk factors, clinical course, therapy, complications and outcome. Prospectively acquired data from 1 January 2006 to 31 October 2007 are now available from two of the study centers. Results: During this period 263 patients with SAB were identified. 52% of patients had hospital-acquired infections, 28% had non-nosocomial but healthcare-associated infections, and 20% had community-acquired infections. The mean patient age was 61 years, 38% of patients were female. 62% of the patients had primary bloodstream infections, while 38% had a secondary bacteremia, diagnosed on the basis of an underlying organ infection with S. aureus. The mean duration of bacteremia was 3.3 days. Average duration of hospitalization was 27 days. The seven-day mortality was 8% and in-hospital mortality 22%. Conclusions: SAB is a common infection in Germany with a serious prognosis.