1. 1Field Epidemiology Services, National Infection Service, Public Health England, London, UK
2. 2UK Surgeon General Headquarters, DMS Whittington, Lichfield, Staffordshire, UK
3. 3Gastrointestinal Bacteria Reference Unit, Public Health England, Colindale, London, UK
4. 4NIHR Health Protection Research Unit in Gastrointestinal Infections, Liverpool, UK
5. 5Barts Health National Health Service Trust, Public Health England, London, UK
6. 6South West Health Protection Team, Public Health England, Bristol, UK