1. Department of Neonatology and Neonatal Intensive Care, Medical University of Bialystok, M. C. Sklodowskiej 24a Street, 15-276 Białystok, Poland
2. Department of Pediatrics and Nephrology, Medical University of Bialystok, 15-269 Bialystok, Poland
3. Department of Hygiene, Epidemiology and Ergonomic, Medical University of Bialystok, 15-269 Bialystok, Poland
4. Department of Pediatric Laboratory Diagnostics, Medical University of Bialystok, 15-269 Bialystok, Poland