Aspergillus fumigatus Detection and Risk Factors in Patients with COPD–Bronchiectasis Overlap

Abstract

The role of Aspergillus fumigatus in the airways of chronic obstructive pulmonary disease (COPD) patients with bronchiectasis is currently unclear. We searched for a sensitive and noninvasive method for A. fumigatus detection in the sputum of COPD patients and addressed potential risk factors for its presence. Induced sputum samples of 18 COPD patients and 17 COPD patients with bronchiectasis were analyzed for the presence of A. fumigatus by culture, galactomannan detection, and PCR. Of the patients with COPD–bronchiectasis overlap, 23.5% had a positive culture for A. fumigatus versus 10.5% of COPD patients without bronchiectasis ( p = 0.39). The median sputum galactomannan optical density index was significantly higher in patients with COPD and bronchiectasis compared with patients with COPD alone ( p = 0.026) and ranged between the levels of healthy controls and A. fumigatus-colonized cystic fibrosis patients. Both the presence of bronchiectasis and the administration of systemic corticosteroids were associated with sputum galactomannan ( p = 0.0028 and p = 0.0044, respectively) and showed significant interaction ( p interaction = 0.022). PCR for Aspergillus was found to be a less sensitive method, but was critically dependent on the extraction technique. The higher sputum galactomannan levels suggest a more abundant presence of A. fumigatus in the airways of patients with COPD–bronchiectasis overlap compared with patients with COPD without bronchiectasis, particularly when systemic corticosteroids are administered.