1. Department of Medical Microbiology and Infection Control, Vrije Universiteit Medical Center, 1081 BT Amsterdam, Netherlands
2. Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, 3015 GD Rotterdam, Netherlands
3. Department of Molecular Cell Biology and Immunology, Vrije Universiteit Medical Center, 1081 BT Amsterdam, Netherlands
4. Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, Netherlands
5. Department of Gastroenterology, Vrije Universiteit Medical Center, 1081 BT Amsterdam, Netherlands
6. Division of Gastroenterology, GastroZentrum Kreuzlingen, 8280 Kreuzlingen, Switzerland