1. Department of Gastroenterology 401 General Military Hospital of Athens Attiki Greece
2. Department of Gastroenterology University Hospital of Larisa Larisa Greece
3. Department of Microbiology “Agia Sofia” Hospital Athens Greece
4. Division of Gastroenterology & Hepatology Medical University Department Kantonsspital Aarau Aarau Switzerland
5. Department of Internal Medicine Second Medical Clinic Ippokration Hospital Aristotle University of Thessaloniki Thessaloniki Greece