1. Department of Medical Microbiology, Malmö University Hospital, Entrance 78, S-20502 Malmö, Sweden
2. Institute of Biotechnology, Graiciuno 8, LT-2028, Vilnius, Lithuania
3. Department of Microbiology, National Public Health Institute, PO Box 310 (Aapistie 1), FIN-90101 Oulu, Finland
4. Department of Infectious Disease Epidemiology, National Public Health Institute, Mannerheimintie 166, FIN-00300 Helsinki, Finland