Dissociation between sensitizing and colonizing fungi in patients with allergic bronchopulmonary aspergillosis

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.

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

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.

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.

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.