1. Intensive Care Unit, University Hospital of Ioannina, 45500 Ioannina, Greece
2. UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4029, Australia
3. Second Critical Care Department, Attikon University Hospital, Rimini Street, 12462 Athens, Greece
4. Department of Microbiology, University Hospital of Ioannina, 45500 Ioannina, Greece