Dissociation Between Sensitizing and Colonizing Fungi in Patients with Allergic Bronchopulmonary Aspergillosis

Background: Because allergic bronchopulmonary aspergillosis (ABPA) does not require the presence of Aspergillus fumigatus for diagnosis, serological and radiological findings without cultures usually confirm this condition.

Objective: To determine which fungi colonize the airways of patients with definitive ABPA.

Methods: We enrolled 11 patients (ages 57.5 ± 17.1 years; male: female, 4:7) with ABPA diagnosed by serological and radiological criteria. Fungi colonizing the airway were identified from mucous plugs that were naturally expectorated or obtained by fiberoptic bronchoscopy.

Results: Aspergillus spp. (n = 8) was the most frequently isolated, followed by Schizophyllum commune (n = 4), Candida albicans (n = 2), Rhizopus oryzae (n = 1), and Penicillium spp. (n = 1). Among the Aspergillus spp., A. niger, A. terreus, and A. sydowii were more frequently isolated (total, n = 6) than A. fumigatus (n = 2). Many patients were sensitized with several fungi in addition to Aspergillus, which were dissociated with airway-colonizing fungi.

Conclusion: Multiple fungal species can colonize the airway, and dissociation between colonizing and sensitizing species frequently occurs in definitive ABPA. Considering the increased prevalence of azole-resistant Aspergillus spp., administering antifungal drugs that target A. fumigatus without identifying which fungal species colonize the airway might be problematic.