1. Medical University Department of Medicine, Kantonsspital Aarau, 5001 Aarau, Switzerland
2. Department of Infectious Diseases and Hospital Hygiene, Kantonsspital Aarau, 5001 Aarau, Switzerland
3. Medical Faculty, University of Basel, 4056 Basel, Switzerland
4. Institute of Laboratory Medicine, Kantonsspital Aarau, 5001 Aarau, Switzerland