1 Guy's and St Thomas' NHS Foundation Trust, Westminster Bridge Road, London, SE1 7EH, UK; National Institute for Healthcare Research Health Protection Research Unit (NIHR HPRU) in HCAI and AMR, Imperial College London & Public Health England, Hammersmith Hospital, Du Cane Road, W12 0HS, UK. Electronic address: jon.otter@gstt.nhs.uk.
2 Guy's and St Thomas' NHS Foundation Trust, Westminster Bridge Road, London, SE1 7EH, UK.