1. Division of Medical Microbiology, Faculty of Health Sciences, Linköping University, 58185 Linköping, Sweden
2. Department of Clinical Microbiology and Infectious Diseases, Kalmar County Hospital, 391 85 Kalmar, Sweden
3. Scientific Institute of Public Health, Operational Domain of Communicable and Infectious Diseases-Site Ukkel, Program of Immunology and Vaccinology, B1180 Brussels, Belgium