1. Department of Microbiology and Immunology, Medical Faculty, University of Nis, 18000 Nis, Serbia
2. Centre of Microbiology, Public Health Institute Nis, 18000 Nis, Serbia
3. Department of Biology, Faculty of Science and Mathematics, University of Nis, 18000 Nis, Serbia
4. Department of Chemistry and Chemical Technology, Faculty of Technology, University of Nis, 18000 Nis, Serbia
5. Department of Dental Health Care, Health Center Niš, 18000 Nis, Serbia
6. Department of Medical Statistics and Informatics, Medical Faculty, University of Nis, 18000 Nis, Serbia
7. Department of Microbiology and Immunology, Medical Faculty, University of Belgrade, 11000 Belgrade, Serbia