1. Robert-Koch-Institute, FG13 Nosocomial Infections, Wernigerode, Germany.
2. Department of Internal Medicine II, University of Tübingen, Tübingen, Germany.
3. Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany.
4. Institute of Medical Microbiology and Hygiene, Eberhard Karls University of Tübingen, Tübingen, Germany.