1 Division of Medicine, Bloomsbury Institute for Intensive Care Medicine, University College London, Cruciform Building, Gower St, London WC1E 6BT, United Kingdom.
2 Department of Clinical Microbiology, University College London NHS Foundation Trust, London, United Kingdom.
3 Division of Medicine, Bloomsbury Institute for Intensive Care Medicine, University College London, Cruciform Building, Gower St, London WC1E 6BT, United Kingdom. Electronic address: [email protected].