How to Assess Fungal Contamination of Indoor Air in Dwellings of Patients with Cystic Fibrosis?

Abstract

Chronic colonization by filamentous fungi in patients with cystic fibrosis (pwCF) is linked to declines in lung function and quality of life. To better assess indoor mold exposure, 23 French dwellings of pwCF from CF care centers in Normandy and Maine & Loire, France were visited. Bioaerosols collected using Coriolis® µ and Coriolis® compact biocollectors and dust were cultured on four different media: Potato Dextrose Agar (PDA), Malt Extract Agar (MEA), Sabouraud Chloramphenicol Gentamicin (SCG) and Sabouraud Chloramphenicol Gentamicin Actidione (S +). A total of 164 fungal species were identified (44 in both air and dust, 77 in air only and 43 in dust only), with no significant difference in average species count between air and dust samples (p = 0.353). The Coriolis® µ biocollector yielded significantly higher species recovery and fungal load from air samples compared to the Coriolis® compact biocollector (p < 0.001 and p < 0.0001, respectively). Higher CFU/m³ for Aspergillus, Fusarium, Mucor and Rhizopus were found on MEA, PDA and SCG media compared to S + (p = 0.037, p = 0.005 and p = 0.030, respectively). Alpha diversity was also greater on MEA, PDA and SCG media than on S + medium (p = 0.001, p < 0.0001 for PDA and SCG) and PDA than on MEA (p = 0.008). The distribution of common fungal genera was consistent with literature, except for higher frequencies of Fusarium and Talaromyces in our study. In conclusion, air sampling with the Coriolis® µ biocollector and inoculation on PDA or MEA media is recommended for this type of field study.