1. First Department of Propedeutic Surgery, Hippocration General Hospital, National Kapodistrian University of Athens, Athens, Greece
2. Department of Upper Gastrointestinal Surgery, Northern General Hospital, Sheffield Teaching Hospitals NHS Trust, Sheffield, United Kingdom
3. Department of General Surgery, York Hospital, York Teaching Hospital NHS Trust, York, United Kingdom
4. Department of Microbiology, Areteion University Hospital, Athens, Greece