title: Early bacteremia in pediatric hematopoietic stem cell transplant patients on oral antibiotic prophylaxis.
abstract: BACKGROUND
  Bacteremia occurs during hematopoietic stem cell transplant (HSCT) in 20%-25% of patients and the use of gut decontamination (GD) to decrease this risk is controversial. Our purpose was to determine the incidence of bacteremia and antimicrobial resistance post-HSCT in pediatric patients receiving GD, and to identify risk factors associated with infection.
  
  
  METHODS
  This was a retrospective cohort study of 182 pediatric patients undergoing first HSCT for malignant disease at The Children's Hospital of Philadelphia from January, 1999 to December, 2002. We examined the impact of age, sex, race, diagnosis, disease status, conditioning regimen, recent bacteremia, stem cell source, donor, graft versus host disease prophylaxis agents, and mucositis severity using Cox proportional hazard models. GD consisted of amoxicillin (azithromycin, if penicillin allergic) and oral gentamicin. Outcome was first episode of bacteremia prior to absolute neutrophil count (ANC) 500/mm(3). Antibiotic susceptibilities were performed on all isolates.
  
  
  RESULTS
  Seventy-four patients (41%) developed bacteremia. The majority were Gram-positive cocci, with Staphylococcal (50%) and Streptococcal species (28%) the most common. Gram-negative organisms were identified in 22% with Pseudomonas (5.7%) and Klebsiella species (3.4%) the most common. Of the Streptococcal infections, 72% were resistant to ampicillin; only 25% of the Gram-negative bacteria were resistant to gentamicin. Race was the only factor associated with early bacteremia (hazard ratio 2.3 for non-Caucasian, non-African-American patients, CI 1.3-4.3, P = 0.007).
  
  
  CONCLUSIONS
  Early bacteremia is common after HSCT, despite the use of GD. Resistant Gram-positive organisms predominate, consistent with recent trends in immunocompromised patients. Although used in practice, there is no clear evidence for the efficacy of GD and this study provides the basis upon which to develop a randomized clinical trial evaluating the current GD regimen with placebo.
authors.affiliation: Department of Pediatrics, Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA. segall@email.chop.edu
authors.forename: Leslie S
authors.initials: LS
authors.lastname: Kersun
authors.forename: Kathleen J
authors.initials: KJ
authors.lastname: Propert
authors.forename: Ebbing
authors.initials: E
authors.lastname: Lautenbach
authors.forename: Nancy
authors.initials: N
authors.lastname: Bunin
authors.forename: Angela
authors.initials: A
authors.lastname: Demichele
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D019072:Antibiotic Prophylaxis; D016470:Bacteremia / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology / Q000517:prevention & control*; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D009369:Neoplasms / Q000628:therapy*; D010414:Pennsylvania / Q000453:epidemiology; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors