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