[1] Medical University of Vienna,Division of Gastroenterology and Hepatology, Department of Internal Medicine III
[2] Hospital Brothers of St. John of God,Department of Internal Medicine
[3] Medical University of Vienna,Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine I
[4] Medical University of Graz,Division of Gastroenterology and Hepatology, Department of Internal Medicine
[5] Medical University of Graz,Division of Phoniatrics, Department of Otorhinolaryngology
[6] Medical University of Graz,Department of Pathology