1. Departments of Molecular and Structural Biology1 and Medical Microbiology and Immunology4, University of Aarhus, DK-8000 Aarhus C, Denmark
2. Departments of Clinical Biochemistry2 and Clinical Microbiology5, Aalborg Hospital, DK-9000 Aalborg, Denmark
3. Department of Clinical Microbiology, Statens Serum Institut, DK-2300 Copenhagen S, Denmark3