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

Franziska A. Stressmann, Geraint B. Rogers, Peter Marsh, Andrew K. Lilley, Thomas W V Daniels, Mary P. Carroll, Lucas R. Hoffman, Graeme Jones, Collette E. Allen, Nilesh Patel, Benjamin Forbes, Andrew Tuck, Kenneth D. Bruce

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99 Citations (Scopus)


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 0days 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.

Original languageEnglish
Pages (from-to)357-365
Number of pages9
JournalJournal of Cystic Fibrosis
Issue number5
Publication statusPublished or Issued - Sep 2011


  • Bacterial enumeration infection molecular respiratory

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Pulmonary and Respiratory Medicine

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