1. Department of Paediatrics and Adolescent Medicine, Turku University Hospital and University of Turku, Turku, Finland
2. Institute of Biomedicine, University of Turku, Turku, Finland
3. Department of Clinical Microbiology, Turku University Hospital, Turku, Finland
4. Department of Pediatrics, Seinäjoki Central Hospital, Seinäjoki, Finland