Affiliation: | 1. Primary Care Unit, Health Protection Agency, , Gloucester, UK;2. Department of Gastroenterology, Gloucestershire Royal Hospital, , Gloucester, UK;3. Statistics Unit, Health Protection Agency, , London, UK;4. Microbiology, Ysbyty Gwynedd, , Bangor, UK;5. Laboratory of Gastrointestinal Pathogens, Health Protection Agency, Centre for Infections, , Colindale, UK;6. Institute of Medical Microbiology & Hygiene, University Hospital Freiburg, , Freiburg, Germany |