Send to

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

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

Author information

Molecular Microbiology Research Laboratory, Institute of Pharmaceutical Sciences, 150 Stamford Street, Franklin-Wilkins Building, King's College London, London, SE1 9NH, UK.



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.


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.


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.


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.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center