1. Department of Pediatric Oncology, Hematology and Transplantology, University of Medical Sciences, Poznan, Poland.
2. Department of Oncology and Children's Memorial Health Institute, Warszawa, Poland.
3. Department of Microbiology, Children's Memorial Health Institute, Warszawa, Poland.
4. Department of Pediatric Hematology and Oncology and Collegium Medicum, Nicolaus Copernicus University Torun, Bydgoszcz, Poland.
5. Department of Microbiology, Collegium Medicum, Nicolaus Copernicus University Torun, Bydgoszcz, Poland.
6. Department of Pediatric Hematology and Oncology, Medical University, Warszawa, Poland.
7. Department of Pediatric Oncology, Hematology and Diabetology, Medical University, Lodz, Poland.
8. Division of Pediatric Hematology and Oncology, Children Hospital, Olsztyn, Poland.
9. Department of Pediatrics, Hematology and Oncology, Medical University, Gdansk, Poland.
10. Department of Pediatrics, Hemato-Oncology and Gastroenterology and Pomeranian Medical University, Szczecin, Poland.
11. Department of Pediatrics and Oncology, Pomeranian Medical University, Szczecin, Poland.
12. Division of Pediatric Oncology, Hematology and Chemotherapy, Department of Pediatric, Silesian Medical University, Katowice, Poland.
13. Department of Pediatric Stem Cell Transplantation, Hematology and Oncology, Medical University, Wroclaw, Poland.
14. Department of Pediatric Oncology and Hematology and University Children's Hospital, Jagiellonian University, Collegium Medicum, Krakow, Poland.
15. Department of Microbiology, University Children's Hospital, Jagiellonian University, Collegium Medicum, Krakow, Poland.
16. Division of Pediatric Hematology and Oncology, Chorzow Pediatric and Oncology Center, Chorzow, Poland.
17. Department of Pediatric Hematology and Oncology, Silesian Medical University, Zabrze, Poland.
18. Department of Pediatric Oncology and Hematology, Medical University, Bialystok, Poland.
19. Division of Pediatric Hematology and Oncology, Children Hospital, Kielce, Poland.
20. Department of Pediatric Oncohematology, Children Hospital, Rzeszow, Poland.
21. Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, Medical University, Lublin, Poland.