1. Clinic of Otorhinolaryngology and Maxillofacial Surgery, University Clinical Centre of Serbia, Belgrade, Serbia
2. University of Belgrade-Faculty of Medicine, Belgrade, Serbia
3. Department of Microbiology and Immunology, University of Belgrade-Faculty of Pharmacy, Belgrade, Serbia
4. Institute for Laboratory Diagnostics “Konzilijum”, Belgrade, Serbia
5. Institute of Microbiology and Immunology, Belgrade, Serbia