1. Infectious Diseases Unit, Department of Medicine, University General Hospital of Ioannina, University of Ioannina, St. Niarchou, 455 00 Ioannina, Greece
2. Faculty of Medicine, University of Ioannina, 451 10 Ioannina, Greece
3. Department of Internal Medicine, G. Papanikolaou General Hospital of Thessaloniki, 570 10 Thessaloniki, Greece