1. 1Department of Gastrointestinal Infections, Health Protection Agency Centre for Infections, 61 Colindale Avenue, London NW9 5EQ, UK
2. 2Microtech Services (Wessex) Limited, 1 Kinson Road, Bournemouth BH10 4AQ, UK
3. 3Health Protection Agency London Food, Water and Environmental Microbiology Services Laboratory, 61 Colindale Avenue, London NW9 5EQ, UK
4. 4Health Protection Agency North West Manchester Laboratory, Manchester Royal Infirmary, Manchester M13 9WZ, UK
5. 5Microbiology Laboratory NPHS for Wales, Llandough Hospital, Penlan Road, Penarth CF64 2XX, UK
6. 6Bacteriology Department, Belfast City Hospital Trust, Lisburn Road, Belfast BT9 7AB, UK
7. 7Public Analyst Laboratory, Glasgow Scientific Services, 64 Everard Drive, Glasgow G21 1XG, UK
8. 8Food Standards Agency, Microbiological Safety Division, Aviation House, 125 Kingsway, London WC2B 6NH, UK