Landscape-scale exposure to multiazole-resistant Aspergillus fumigatus bioaerosols

We demonstrate country-wide exposures to aerosolized spores of a human fungal pathogen, Aspergillus fumigatus, that has acquired resistance to first line azole clinical antifungal drugs. Assisted by a network of citizen scientists across the United Kingdom, we show that 1 in 20 viable aerosolized spores of this mold are resistant to the agricultural fungicide tebuconazole and 1 in 140 spores are resistant to the four most used azoles for treating clinical aspergillosis infections. Season and proximity to industrial composters were associated with growth of A. fumigatus from air samples, but not with the presence of azole resistance, and hotspots were not stable between sampling periods suggesting a high degree of atmospheric mixing. Genomic analysis shows no distinction between those resistant genotypes found in the environment and in patients, indicating that ~40% (58/150 sequenced genomes) of azole-resistant A. fumigatus infections are acquired from environmental exposures. Due to the ubiquity of this measured exposure, it is crucial that we determine source(s) of azole-resistant A. fumigatus, who is at greatest risk of exposure and how to mitigate these exposures, in order to minimize treatment failure in patients with aspergillosis. ### Competing Interest Statement The authors have declared no competing interest.