1. Department of Pediatric Oncology, Hematology and Transplantology; University of Medical Sciences; Poznan Poland
2. Department of Pediatric Stem Cell Transplantation, Hematology and Oncology; Medical University; Wroclaw Poland
3. Department of Pediatric Hematology and Oncology; Collegium Medicum; Nicolaus Copernicus University; Bydgoszcz Poland
4. Department of Microbiology; Collegium Medicum; Nicolaus Copernicus University Torun; Bydgoszcz Poland
5. Department of Microbiology; University Children's Hospital Department of Clinical Immunology and Transplantology; Jagiellonian University Collegium Medicum; Krakow Poland
6. Stem Cell Transplant Center; University Children's Hospital Department of Clinical Immunology and Transplantology; Jagiellonian University Collegium Medicum; Krakow Poland
7. Department of Pediatric Hematology, Oncology and Stem Cell Transplantation; Medical University; Lublin Poland