Does bacterial density in cystic fibrosis sputum increase prior to pulmonary exacerbation?

J Cyst Fibros. 2011 Sep;10(5):357-65. doi: 10.1016/j.jcf.2011.05.002. Epub 2011 Jun 12.

Abstract

Background: Cystic Fibrosis (CF) lung disease is characterised by an inexorable decline in lung function, punctuated by periods of symptomatic worsening known as pulmonary exacerbations (referred to here as CFPE). Despite their clinical significance, the cause of CFPE remains undetermined. It has been suggested that an increase in bacterial density may be a trigger, although this has not been shown empirically.

Methods: Here, a previously validated quantitative PCR-based approach was used to assess numbers of Pseudomonas aeruginosa and of total bacteria in respiratory secretions from patients during the period leading up to CFPE. Sputum samples collected from 12 adult CF patients were selected retrospectively to fall approximately 21, 14, 7 and 0 days prior to CFPE diagnosis. In addition, the relationships between clinical parameters (FEV(1), temperature and patient reported outcome measures) and microbiological data were investigated.

Results: No significant changes either in total bacterial or P. aeruginosa numbers were identified prior to CFPE. Of all the correlations tested, only temperature showed a significant correlation with total bacterial numbers in the period leading to CFPE.

Conclusions: These findings strongly suggest that CFPE do not generally result from increased bacterial density within the airways. Instead, data presented here are consistent with alternative models of pulmonary exacerbation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Anti-Bacterial Agents / therapeutic use
  • Bacterial Load*
  • Cystic Fibrosis / microbiology*
  • Cystic Fibrosis / physiopathology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pneumonia, Bacterial / diagnosis
  • Pneumonia, Bacterial / drug therapy
  • Pneumonia, Bacterial / microbiology*
  • Pneumonia, Bacterial / physiopathology
  • Pseudomonas Infections / diagnosis
  • Pseudomonas Infections / drug therapy
  • Pseudomonas Infections / microbiology*
  • Pseudomonas Infections / physiopathology
  • Pseudomonas aeruginosa / genetics
  • Pseudomonas aeruginosa / growth & development*
  • Pseudomonas aeruginosa / isolation & purification
  • Real-Time Polymerase Chain Reaction
  • Respiratory Function Tests
  • Severity of Illness Index
  • Sputum / microbiology*
  • Young Adult

Substances

  • Anti-Bacterial Agents