1. School of Infection and Immunity, University of Birmingham, Birmingham B15 2TT, United Kingdom
2. Health Protection Agency, West Midlands Public Health Laboratory, Heart of England NHS Foundation Trust, Birmingham B9 5SS, United Kingdom
3. Anaerobe Reference Unit, National Public Health Service Microbiology Cardiff, University Hospital of Wales, Cardiff, United Kingdom
4. Health Protection Agency, Centre for Infections, 61 Colindale Avenue, London NW9 5EQ, United Kingdom