1. Health Protection Agency, West Midlands North, Stafford, United Kingdom
2. Health Protection Agency West Midlands, Birmingham, United Kingdom
3. Health Protection Agency, Microbiology Services, Reference Microbiology Services, Colindale, United Kingdom
4. Health Protection Agency Health Protection Services, Colindale, United Kingdom
5. University Hospital of North Staffordshire NHS Trust, Stoke-on-Trent, United Kingdom
6. Health Protection Agency, Microbiology Services, Food, Water and Environmental Microbiology Laboratory (Birmingham), Sutton Coldfield, United Kingdom
7. National Health Service Stoke-on-Trent, Stoke-on-Trent, United Kingdom