1. Department of Microbiology, National Veterinary Research Institute, 24-100 Pulawy, Poland
2. Scottish Salmonella Shigella and Clostridium difficile Reference Laboratory, Stobhill Hospital, G21 3UW Glasgow, Scotland
3. Research Department, Veterinary Bacteriology, Finnish Food Safety Authority Evira, 70210 Kuopio, Finland
4. Centre for Infectious Disease Control, Laboratory for Infectious Diseases and Perinatal Screening, National Institute of Public Health and the Environment (RIVM), 3721 MA Bilthoven, Netherlands