1. Department of Gastroenterology, Infectious Diseases, and Rheumatology, Campus Benjamin Franklin, Charité-University Medicine Berlin, 13125 Berlin, Germany
2. Institute of Nutrition, University of Potsdam, 14558 Nuthetal, Germany
3. Institute for Medical Microbiology and Hospital Hygiene, Philipps University of Marburg, 35043 Marburg, Germany