title: Diagnosis of bacteremia in febrile neutropenic episodes in children with cancer: microbiologic and molecular approach.
abstract: BACKGROUND
  Bacterial isolation using conventional microbiologic techniques rarely surpasses 25% in children with clinical and laboratory findings indicative of an invasive bacterial infection. The aim of this study was to determine the role of real-time polymerase chain reaction (RT-PCR) from whole blood samples compared with automated blood cultures (BC) in detection of relevant microorganisms causing bacteremia in episodes of high-risk febrile neutropenia (HRFN) in children with cancer.
  
  
  METHODS
  Children presenting with HRFN at 6 hospitals in Santiago, Chile, were invited to participate. Blood samples were obtained at admission for BC, and at admission and 24 hours for RT-PCR targeting DNA of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa causing bacteremia in children with HRFN.
  
  
  RESULTS
  A total of 177 HRFN episodes were evaluated from May 2009 to August 2010, of which 29 (16.3%) had positive BC, 9 (5%) positive for 1 of the 3 selected bacterial species: 5 for E. coli, 3 for S. aureus, and 1 for P. aeruginosa. RT-PCR detected 39 bacteria in 36 episodes (20%): 14 E. coli, 20 S. aureus, and 5 P. aeruginosa. The sensitivity, specificity, and positive and negative predictive values of RT-PCR compared with BC were 56%, 80%, 13%, and 97%. The final clinical diagnosis was compatible with an invasive bacterial infection in 30/36 (83%) RT-PCR-positive episodes.
  
  
  CONCLUSIONS
  In our series, RT-PCR significantly improved detection of the most relevant bacteria associated with HRFN episodes. Large number of patients and close clinical monitoring, in addition to improved RT-PCR techniques will be required to fully recommend RT-PCR-based diagnosis for the routine workup of children with cancer, fever, and neutropenia.
authors.affiliation: Department of Pediatrics, Hospital L. Calvo Mackenna, Faculty of Medicine, Universidad de Chile, Santiago, Chile. msantola@med.uchile.cl
authors.forename: María E
authors.initials: ME
authors.lastname: Santolaya
authors.forename: Mauricio J
authors.initials: MJ
authors.lastname: Farfán
authors.forename: Verónica
authors.initials: V
authors.lastname: De La Maza
authors.forename: Manuela
authors.initials: M
authors.lastname: Cociña
authors.forename: Felipe
authors.initials: F
authors.lastname: Santelices
authors.forename: Ana M
authors.initials: AM
authors.lastname: Alvarez
authors.forename: Carmen L
authors.initials: CL
authors.lastname: Avilés
authors.forename: Ana
authors.initials: A
authors.lastname: Becker
authors.forename: Miguel
authors.initials: M
authors.lastname: O'Ryan
authors.forename: Paulina
authors.initials: P
authors.lastname: Román
authors.forename: Carmen
authors.initials: C
authors.lastname: Salgado
authors.forename: Pamela
authors.initials: P
authors.lastname: Silva
authors.forename: Santiago
authors.initials: S
authors.lastname: Topelberg
authors.forename: Juan
authors.initials: J
authors.lastname: Tordecilla
authors.forename: Mónica
authors.initials: M
authors.lastname: Varas
authors.forename: Milena
authors.initials: M
authors.lastname: Villarroel
authors.forename: Tamara
authors.initials: T
authors.lastname: Viviani
authors.forename: Marcela
authors.initials: M
authors.lastname: Zubieta
authors.forename: Juan P
authors.initials: JP
authors.lastname: Torres
mesh_terms: D000293:Adolescent; D016470:Bacteremia / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology; D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D002677:Chile; D004926:Escherichia coli / Q000145:classification / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology; D005260:Female; D005334:Fever / Q000097:blood / Q000150:complications / Q000382:microbiology; D006801:Humans; D008297:Male; D009369:Neoplasms / Q000097:blood / Q000150:complications / Q000382:microbiology; D009503:Neutropenia / Q000097:blood / Q000150:complications / Q000382:microbiology; D009504:Neutrophils / Q000166:cytology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011552:Pseudomonas Infections / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000302:isolation & purification*; D060888:Real-Time Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification / Q000302:isolation & purification*