title: Bacterial infections in pediatric hematopoietic stem cell transplantation recipients: incidence, epidemiology, and spectrum of pathogens: report of the Polish Pediatric Group for Hematopoietic Stem Cell Transplantation.
abstract: BACKGROUND
  Infectious complications are a significant cause of hematopoietic stem cell transplantation (HSCT) failure, especially allogeneic HSCT (allo-HSCT) because of delayed immune reconstitution and graft-versus-host disease (GVHD) occurrence. Identifying the factors responsible for bacterial infections (BI) in patients undergoing HSCT will provide much more effective empirical antimicrobial treatment in this group of patients.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the epidemiology and profile of BI in patients after HSCT in 5 centers of the Polish Pediatric Group for Hematopoietic Stem Cell Transplantation in 2012-2013.
  
  
  METHODS
  In 308 HSCT recipients, we retrospectively analyzed 273 episodes of BI in 113 (36.7%) children aged 0.02-22 years (median age: 7 years), 92 after allo-HSCT and 22 after autologous HSCT (auto-HSCT). We assessed incidence of BI in different HSCT types by calculating the Index of Bacterial Infection (IBI) as a ratio of patients with at least 1 BI to all patients who underwent this type of HSCT in the analyzed period. We assessed the profile of BI with particular emphasis on multidrug-resistant organisms, and impact of underlying disease and of graft-versus-host disease on BI episodes.
  
  
  RESULTS
  In the studied group, 273 episodes of BI were diagnosed, including 237 episodes after allo-HSCT and 36 after auto-HSCT. Among allo-HSCT recipients diagnosed with at least 1 BI, the IBI was 0.4 (matched sibling donor-HSCT 0.3; matched donor-HSCT 0.4; mismatched unrelated donor [MMUD]-HSCT 0.8; P = 0.027) and after auto-HSCT 0.3 per 1 transplanted patient. In patient after allo-HSCT because of myelo- or lymphoproliferative diseases and bone marrow failures, the major cause of infections was Enterobacteriaceae, while gram-positive bacteria predominated in the group with primary immunodeficiencies. In all patients after auto-HSCT, the dominant pathogen of BI were Enterobacteriaceae (P = 0.011). Time from each type of HSCT to infection caused by different pathogens did not differ significantly.
  
  
  CONCLUSIONS
  The risk of BI does not depend on the underlying disease, but only on HSCT donor type and is the highest after MMUD-HSCT procedure. The profile of BI depends on the underlying disease and HSCT donor type, but does not depend on the occurrence of acute GVHD. Gram-negative bacteria predominated in patients with myelo- and lymphoproliferative diseases, while in patients with primary immunodeficiencies gram-positive strains were predominant.
authors.affiliation: Department of Pediatric Oncology, Hematology and Transplantology, University of Medical Sciences, Poznan, Poland. olga_zajac@wp.pl.
authors.forename: O
authors.initials: O
authors.lastname: Zając-Spychała
authors.affiliation: Department of Pediatric Oncology, Hematology and Transplantology, University of Medical Sciences, Poznan, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Wachowiak
authors.affiliation: Department of Pediatric Oncology, Hematology and Transplantology, University of Medical Sciences, Poznan, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Pieczonka
authors.affiliation: Department of Pediatric Stem Cell Transplantation, Hematology and Oncology, Medical University, Wroclaw, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Siewiera
authors.affiliation: Department of Pediatric Stem Cell Transplantation, Hematology and Oncology, Medical University, Wroclaw, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Frączkiewicz
authors.affiliation: Department of Pediatric Stem Cell Transplantation, Hematology and Oncology, Medical University, Wroclaw, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Kałwak
authors.affiliation: Department of Pediatric Stem Cell Transplantation, Hematology and Oncology, Medical University, Wroclaw, Poland.
authors.forename: E
authors.initials: E
authors.lastname: Gorczyńska
authors.affiliation: Department of Pediatric Stem Cell Transplantation, Hematology and Oncology, Medical University, Wroclaw, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Chybicka
authors.affiliation: Department of Pediatric Hematology and Oncology, Collegium Medicum, Nicolaus Copernicus University, Bydgoszcz, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Czyżewski
authors.affiliation: Department of Microbiology, Collegium Medicum, Nicolaus Copernicus University Torun, Bydgoszcz, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Jachna-Sawicka
authors.affiliation: Department of Pediatric Hematology and Oncology, Collegium Medicum, Nicolaus Copernicus University, Bydgoszcz, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Wysocki
authors.affiliation: Department of Microbiology, University Children's Hospital Department of Clinical Immunology and Transplantology, Jagiellonian University Collegium Medicum, Krakow, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Klepacka
authors.affiliation: Stem Cell Transplant Center, University Children's Hospital Department of Clinical Immunology and Transplantology, Jagiellonian University Collegium Medicum, Krakow, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Goździk
authors.affiliation: Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, Medical University, Lublin, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Zaucha-Prażmo
authors.affiliation: Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, Medical University, Lublin, Poland.
authors.forename: J R
authors.initials: JR
authors.lastname: Kowalczyk
authors.affiliation: Department of Pediatric Hematology and Oncology, Collegium Medicum, Nicolaus Copernicus University, Bydgoszcz, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Styczyński
mesh_terms: D000293:Adolescent; D000328:Adult; D001424:Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D024901:Drug Resistance, Multiple, Bacterial; D004755:Enterobacteriaceae / Q000302:isolation & purification*; D005260:Female; D006086:Graft vs Host Disease / Q000150:complications / Q000453:epidemiology*; D006094:Gram-Positive Bacteria / Q000302:isolation & purification*; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D011044:Poland / Q000453:epidemiology; D012189:Retrospective Studies; D014182:Transplantation, Autologous / Q000009:adverse effects; D014184:Transplantation, Homologous / Q000009:adverse effects; D061349:Unrelated Donors; D055815:Young Adult
keywords: bacterial infection; children; epidemiology; hematopoietic stem cell transplantation; multidrug resistance