1. 1Department of Microbiology, Royal Free London NHS Foundation Trust, Royal Free Site, Pond Street, London NW3 2QG, UK
2. 2Centre for Clinical Microbiology, University College London, London, UK
3. 3Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI) Reference Unit, National Infection Service, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK