1. Department of Surgery, Queen Margaret Hospital, NHS Fife, Dunfermline, Fife, Scotland, United Kingdom.
2. Epidemiology and Statistics Core, Wellcome Trust Clinical Research Facility, University of Edinburgh, Edinburgh, Scotland, United Kingdom.
3. Department of Microbiology, Victoria Hospital Kircaldy, NHS Fife, Kircaldy, Fife, Scotland, United Kingdom.