Impact of Pseudomonas and Staphylococcus infection on inflammation and clinical status in young children with cystic fibrosis

J Pediatr. 2009 Feb;154(2):183-8. doi: 10.1016/j.jpeds.2008.08.001. Epub 2008 Sep 25.


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).

Study design: 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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Biomarkers / metabolism
  • Bronchoalveolar Lavage Fluid / microbiology*
  • Bronchoscopy
  • Child, Preschool
  • Cross-Sectional Studies
  • Cystic Fibrosis / physiopathology*
  • Exotoxins / metabolism
  • Female
  • Humans
  • Inflammation / physiopathology*
  • Interleukin-8 / metabolism
  • Leukocyte Count
  • Leukocyte Elastase / metabolism
  • Lung / microbiology*
  • Lung / physiopathology
  • Male
  • Neutrophils / metabolism
  • Oropharynx / microbiology
  • Pseudomonas Infections / diagnosis*
  • Pseudomonas aeruginosa
  • Severity of Illness Index
  • Staphylococcal Infections / diagnosis*
  • Staphylococcus aureus


  • Biomarkers
  • Exotoxins
  • Interleukin-8
  • Leukocyte Elastase