Respiratory pathogens are frequently isolated from the airways in patients with chronic obstructive pulmonary disease ( COPD ) in the absence of an exacerbation.
This bacterial colonization by potential pathogens is associated with host inflammatory and immune responses.
Researchers have assessed whether bacterial colonization impacts daily symptoms in COPD.
In a longitudinal prospective observational study of COPD, patients recorded daily symptoms electronically as the Breathlessness, Cough, and Sputum Scale ( BCSS ).
Sputum cultures and quantitative polymerase chain reaction ( PCR ) were performed every two weeks.
A total of 41 patients recorded daily symptoms for 12527 days. Average BCSS score was higher during the periods of colonization determined by sputum culture with one or more of the following pathogens: nontypeable Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, and Pseudomonas aeruginosa, compared to periods without colonization ( 5.28 vs 4.46, p=0.008 ) after controlling for confounding variables.
The finding did not change when colonization was defined by quantitative PCR ( average BCSS 4.77 vs 4.25, p=0.006 ).
Sputum interleukin-8 levels were elevated with bacterial colonization.
In conclusion, even in the absence of clinical exacerbation, colonization by bacterial pathogens in COPD was associated with a clinically significant moderate increase in daily symptoms, likely mediated by increased airway inflammation.
Therapies that decrease bacterial colonization in COPD could improve daily symptoms and quality of life in this chronic debilitating disease. ( Xagena )
Desai H et al, Ann Am Thorac Soc 2014; Epub ahead of print