1. Institute of Medical Microbiology and Hygiene, Saarland University, Homburg/Saar, Germany
2. Department of Thoracic and Cardiovascular Surgery, Saarland University, Homburg/Saar, Germany
3. Hospital Pharmacy, Saarland University, Homburg/Saar, Germany
4. Institute of Hygiene, University Hospital Münster, Münster, Germany