1. Public Health England, East Midlands, Leicester, United Kingdom.
2. Public Health England, West Midlands, Birmingham, United Kingdom.
3. Daventry District Council, Daventry, United Kingdom.
4. Microbiological Food Safety, Food Standards Agency, London, United Kingdom.
5. Health Protection Services, Public Health England, Colindale, United Kingdom.
6. Gastrointestinal Bacteria Reference Unit, Microbiological Services, Public Health England, Colindale, United Kingdom.
7. Field Epidemiology Service, Public Health England, Nottingham, United Kingdom.