Detection of microorganisms in exhaled breath condensate during acute exacerbations of COPD

Background: One hallmark of chronic obstructive pulmonary disease (COPD) is colonization and infection of the lung. Exacerbations are acute deteriorations of the chronic disease and are associated with a change of the pulmonary microbiome. The collection of exhaled breath condensate (EBC) can be used to noninvasively determine markers of lung disease. The aim of the present study was to compare the sensitivity of assay based on the detection of microbial nucleic acids from exhaled breath condensate (EBC) and from spontaneous sputum. Methods: EBCs and sputa of 29 adults with acute exacerbation of COPD were obtained. Isolated DNA or RNA were used as starting material for the PCR assays to detect Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, Legionella pneumophila, Mycoplasma pneumoniae, Chlamydia pneumoniae, Influenza viruses (AH 1, AH 3) and respiratory syncytial virus. Results: Bacteria or viruses were identified in 14 EBCs and 21 sputa from 29 patients. Results from EBC did not correlate well with those from sputum. Viruses and S. pneumoniae were detected only in sputum, whereas L. pneumophila was only found in EBC. In 3 EBCs and 10 sputa more than one microorganism was detected. Conclusions: Bacteria can be identified in EBCs of COPD patients with exacerbations and underline that microbial colonization has a role in this condition. Interestingly, the results from EBC don't correlate well with those from sputum.