1. Departments of Nephrology, Cliniques Universitaires St. Luc, Université Catholique de Louvain, Brussels, Belgium
2. Department of Nephrology, Centre Hospitalier, Gilly, Belgium
3. Luxembourg, Clinique Ste. Elisabeth, Gilly, Belgium
4. Namur, Hôpital St. Joseph, Gilly, Belgium
5. Arlon, and Hôpital St. Joseph, Gilly, Belgium
6. Departments of Microbiology, Cliniques Universitaires St. Luc, Université Catholique de Louvain, Brussels, Belgium
7. Departments of Internal Medicine, Cliniques Universitaires St. Luc, Université Catholique de Louvain, Brussels, Belgium