1. Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, 7489 Trondheim, Norway
2. Department of Medical Biochemistry, Institute for Clinical Medicine, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway
3. Department of Microbiology, Oslo University Hospital, and University of Oslo, 0424, Oslo, Norway
4. Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, 2200, Copenhagen N, Denmark