1. University of Kragujevac , Serbia , Faculty of Medical Sciences, Department of Pediatrics
2. Clinical Center Kragujevac, Pediatric Clinic , Kragujevac , Serbia
3. University of Kragujevac , Serbia, Faculty of Medical Sciences, Department of Clinical Pharmacy
4. Medical center ‘’Studenica’’ Kraljevo , Serbia
5. Clinical Center Kragujevac , Department for the control and prevention of hospital infections , Kragujevac , Serbia