Emergence of a Pathogenic Fungus Resistant to Triazole Antifungal Drugs

Over the past 20 years, emerging antifungal resistance has been observed in the human pathogen, Aspergillus fumigatus, and is responsible for serious infections. Resistance in this pathogenic fungus is mainly due to the unintended impact of triazole fungicides widely used in the environment to protect crops and materials from destroying fungi. A. fumigatus is naturally present in the environment and will thus be widely exposed to fungicides, which, through selection pressure, will favour strains that have become resistant. These fungicidal compounds have a chemical structure similar to that of medical compounds, thus rendering them inactive for the treatment of an infection in humans with a resistant strain. A. fumigatus does not cause infections in crops yet fungicidal compounds with activity against this widely present fungus select for an unintended cross-resistance. Therefore, it is important to understand the phenomena leading to resistance in the environment.