Catching more air: An effective and simple-to-use air sampling approach to assess aerial resistance fractions inAspergillus fumigatus

Abstract

AbstractTriazole resistance in the airborne human fungal pathogenAspergillus fumigatusis a significant human health problem as the environmental use of triazoles has selected for cross-resistance to life-saving clinical triazoles in medicine. Despite the environment being well established as a source of triazole resistantA. fumigatusspores, the aerial transmission from the environment to patients remains unclear. This is mainly due to the lack of an affordable, reliable, and simple-to-use method for wide-scale environmental air sampling. Previous methods were ineffective in capturing sufficientA. fumigatuscolony-forming units (CFUs) to allow the quantitative assessment of aerial triazole resistance fractions. Here we show that 14 days of exposure of sticky seals to the air along with selectively culturing colonies directly from the seals proved key for increasing CFUs per sample. We also tested the use of delta traps for passive outdoor spore capture and show that together with the sticky seals and selective culturing, they are a simple and effective tool for outdoor air sampling. We suggest the use of this cost-effective air sampling technique for wide-scale outdoor sampling to map resistance fractions, assess health risks, and pinpoint environmental resistance hot- and coldspots. Doing so will close the knowledge gap between environmental triazole resistance selection and the transmission to patients.