1. Department of Molecular Cell Biology and Immunology, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
2. Department of Surgery, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, the Netherlands
3. Department of Medical Microbiology and Infection Control, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, the Netherlands.
4. Department of Surgery, Spaarne Gasthuis, PO Box 417, 2000 AK Haarlem, the Netherlands