1. Institute of Medical Microbiology; University of Zurich; Zurich; Switzerland
2. Division of Medicine; Hospital Langenthal; Langenthal; Switzerland
3. Division of Cardiovascular Surgery; University Hospital Zurich; Zurich; Switzerland
4. Division of Cardiology; University Hospital Zurich; Zurich; Switzerland
5. Institute of Surgical Pathology; University Hospital Zurich; Zurich; Switzerland
6. Division of Infectious Diseases and Hospital Epidemiology; University Hospital Zurich; Zurich; Switzerland