title: Impact of Pseudomonas and Staphylococcus infection on inflammation and clinical status in young children with cystic fibrosis.
abstract: OBJECTIVE
  To assess the effects of Pseudomonas aeruginosa and Staphylococcus aureus infection on lower airway inflammation and clinical status in young children with cystic fibrosis (CF).
  
  
  METHODS
  We studied 111 children age < 6 years who had 2 P aeruginosa-positive oropharyngeal cultures within 12 months. We examined bronchoalveolar lavage fluid (BALF) inflammatory markers (ie, cell count, differential, interleukin [IL]-8, IL-6, neutrophil elastase), CF-related bacterial pathogens, exotoxin A serology, and clinical indicators of disease severity.
  
  
  RESULTS
  Young children with CF with both upper and lower airway P aeruginosa infection had higher neutrophil counts, higher IL-8 and free neutrophil elastase levels, increased likelihood of positive exotoxin A titers, and lower Shwachman scores compared with those with positive upper airway cultures only. S aureus was associated with increased lower airway inflammation, and the presence of both P aeruginosa and S aureus had an additive effect on concentrations of lower airway inflammatory markers. BALF markers of inflammation were increased with the number of different bacterial pathogens detected.
  
  
  CONCLUSIONS
  Young children with CF who have upper and lower airway P aeruginosa infection have increased endobronchial inflammation and poorer clinical status compared with those with only upper airway P aeruginosa infection. The independent and additive effects of S aureus on inflammation support the significance of polymicrobial infection in early CF lung disease.
authors.affiliation: Department of Pediatrics, The Children's Hospital and University of Colorado Health Sciences Center, Aurora, CO 80045, USA. sagel.scott@tchden.org
authors.forename: Scott D
authors.initials: SD
authors.lastname: Sagel
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Gibson
authors.forename: Julia
authors.initials: J
authors.lastname: Emerson
authors.forename: Sharon
authors.initials: S
authors.lastname: McNamara
authors.forename: Jane L
authors.initials: JL
authors.lastname: Burns
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Wagener
authors.forename: Bonnie W
authors.initials: BW
authors.lastname: Ramsey
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D001999:Bronchoscopy; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000503:physiopathology*; D005098:Exotoxins / Q000378:metabolism; D005260:Female; D006801:Humans; D007249:Inflammation / Q000503:physiopathology*; D016209:Interleukin-8 / Q000378:metabolism; D007958:Leukocyte Count; D019272:Leukocyte Elastase / Q000378:metabolism; D008168:Lung / Q000382:microbiology* / Q000503:physiopathology; D008297:Male; D009504:Neutrophils / Q000378:metabolism; D009960:Oropharynx / Q000382:microbiology; D011552:Pseudomonas Infections / Q000175:diagnosis*; D011550:Pseudomonas aeruginosa; D012720:Severity of Illness Index; D013203:Staphylococcal Infections / Q000175:diagnosis*; D013211:Staphylococcus aureus
chemical_list: D015415:Biomarkers; D005098:Exotoxins; D016209:Interleukin-8; D019272:Leukocyte Elastase