1. Division of Infectious Diseases and Hospital Epidemiology, Department of Internal Medicine, University Hospital of Zurich, University of Zurich, Zurich, Switzerland.
2. Infectiology Department, St. Gallen Cantonal Hospital, St. Gallen, Switzerland.
3. Experimental Infectious Diseases and Cancer Research, Division of Infectious Diseases and Hospital Epidemiology, University Children's Hospital of Zurich, University of Zurich, Zurich, Switzerland.