The roles of bacteria and viruses in COPD-Bronchiectasis association: A prospective cohort study

<bold>Objectives:</bold> To determine the bacterial and viral spectrum at steady-state and exacerbation of COPD-Bronchiectasis association (CBA), and the association between pathogen detection and exacerbations. <bold>Methods:</bold> We prospectively collected sputum from patients with CBA, and bronchiectasis with (BO) and without airflow obstruction (BNO) for bacterial culture and viral detection. <bold>Results:</bold> We enrolled 76 patients with CBA, 58 with BO, and 138 with BNO. Bacterial detection rate increased from BNO, CBA to BO at steady-state (<italic>P</italic>=0.02), but not at exacerbation (<italic>P</italic>=0.91); while no significant differences in viral detection rate were found. Compared with steady-states, viral isolations (V+) occurred more frequently during exacerbation in BNO (<italic>P</italic>=0.001) and CBA (<italic>P</italic>=0.036), but not in BO (<italic>P</italic>=0.904); as did isolation of bacterial plus viral isolation (V+B+). In CBA, isolation of any viruses (OR:1.63, 95%CI[1.11-2.39]), <italic>Human metapneumovirus</italic> (OR:3.55, 1.07-12.52) and bacterial plus viruses (OR:1.68, 1.04-2.71) was associated with exacerbation. Repeated detection of <italic>Pseudomonas aeruginosawas</italic> (<italic>PA</italic>) associated with shorter time to the first exacerbation in CBA (HR=2.07, 1.19-3.61) but not in patients with BO. <bold>Conclusions:</bold> Isolation of any viruses, <italic>Human metapneumovirus</italic> and bacterial plus viruses was associated with CBA exacerbations. Repeated <italic>PA</italic> isolation imposed different impact of future exacerbation on patients with CBA from those with BO. <fig><object-id>erj;64/suppl_68/PA4182/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>