title: Serology as a diagnostic tool for predicting initialPseudomonas aeruginosa acquisition in children with cystic fibrosis.
abstract: BACKGROUND
  Pseudomonas aeruginosa (Pa) serology could potentially be a useful adjunct to respiratory culture methods for the detection of initial or early Pa infection in patients with cystic fibrosis (CF).
  
  
  OBJECTIVE
  To evaluate the utility of Pa serology to predict Pa isolation from respiratory (generally oropharyngeal) cultures in the subsequent 6 or 12 months among young children with CF from whom Pa had never been previously cultured. Pa serology was also evaluated in a group of healthy controls.
  
  
  METHODS
  Children ≤ 12 years of age without prior isolation of Pa from respiratory cultures participating in the Early Pseudomonal Infection Control EPIC Observational Study (EPIC OBS) had annual serum samples for measurement of antibodies against alkaline protease, elastase and exotoxin A using a commercial kit; controls had a single serum sample. Logistic regression with generalized estimating equations was used to characterize associations between log10 serum antibody titers and first isolation of Pa from a respiratory culture within the subsequent 6 or 12 months, with adjustment for sex and age. Receiver operating characteristic curves were used to optimize antibody titer cutpoints by age group. The diagnostic properties of each antibody were estimated using these optimized cutpoints.
  
  
  RESULTS
  Pa serology was evaluated in 582 children with CF (2084 serum samples) and 94 healthy controls. There was substantial overlap between serum antibody titers among controls, CF patients who did not acquire Pa (N = 261) and CF patients who did acquire Pa (N = 321). The maximum positive predictive value for first Pa positive culture within the ensuing 6 months was 76.2% and maximum negative predictive value was 72.1% for any antigen or combination of antigens; values were similar for 12 months.
  
  
  CONCLUSIONS
  Pa serology does not appear useful for predicting first Pa positive oropharyngeal culture among young CF patients.
authors.affiliation: University of Arizona, Tucson, AZ 85724, United States. Electronic address: cdaines@arc.arizona.edu.
authors.forename: Cori
authors.initials: C
authors.lastname: Daines
authors.affiliation: Case Western Reserve University School of Medicine, Cleveland, OH, United States.
authors.forename: Donald
authors.initials: D
authors.lastname: VanDeVanter
authors.affiliation: Seattle Children's Research Institute, Seattle, WA 98121, United States.
authors.forename: Umer
authors.initials: U
authors.lastname: Khan
authors.affiliation: Seattle Children's Hospital, University of Washington School of Medicine, Seattle, WA 98105-0371, United States.
authors.forename: Julia
authors.initials: J
authors.lastname: Emerson
authors.affiliation: Seattle Children's Hospital, University of Washington School of Medicine, Seattle, WA 98105-0371, United States.
authors.forename: Sonya
authors.initials: S
authors.lastname: Heltshe
authors.affiliation: Seattle Children's Hospital, University of Washington School of Medicine, Seattle, WA 98105-0371, United States.
authors.forename: Sharon
authors.initials: S
authors.lastname: McNamara
authors.affiliation: Department of Pediatrics, University of Kentucky, Lexington, KY 40563-0284, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Anstead
authors.affiliation: Mediagnost®, Aspenhaustr. 25, 72770 Reutlingen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Langkamp
authors.affiliation: Institute of Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Doring
authors.affiliation: Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Canada.
authors.forename: Felix
authors.initials: F
authors.lastname: Ratjen
authors.affiliation: Seattle Children's Hospital, University of Washington School of Medicine, Seattle, WA 98105-0371, United States.
authors.forename: Bonnie
authors.initials: B
authors.lastname: Ramsey
authors.affiliation: Seattle Children's Hospital, University of Washington School of Medicine, Seattle, WA 98105-0371, United States.
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Gibson
authors.affiliation: University of Arizona, Tucson, AZ 85724, United States.
authors.forename: Wayne
authors.initials: W
authors.lastname: Morgan
authors.affiliation: Seattle Children's Hospital, University of Washington School of Medicine, Seattle, WA 98105-0371, United States.
authors.forename: Margaret
authors.initials: M
authors.lastname: Rosenfeld
mesh_terms: D000907:Antibodies, Bacterial / Q000032:analysis*; D002648:Child; D003550:Cystic Fibrosis / Q000150:complications*; D005260:Female; D005544:Forecasting; D006801:Humans; D016015:Logistic Models; D008297:Male; D009960:Oropharynx / Q000382:microbiology; D011552:Pseudomonas Infections / Q000175:diagnosis* / Q000276:immunology; D011550:Pseudomonas aeruginosa / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D000907:Antibodies, Bacterial
keywords: Cystic fibrosis; Pseudomonas; ROC curves; Serology