Predicting antifungal concentrations that select for resistance: an enhanced approach to establish environmental thresholds

This 2026 Environmental International study investigates how antifungal drugs in the environment can drive the development of antifungal resistance by identifying the concentrations at which resistance is likely to be selected. Using a large global dataset of fungal susceptibility (over 300,000 isolates), the researchers developed refined “safe threshold” concentrations (PNECRs) for multiple antifungals in water and soil, explicitly accounting for uncertainties in laboratory data. They found that environmental levels of several antifungals—especially in wastewater and surface water—already exceed these thresholds in a notable proportion of samples, indicating a real risk of resistance selection in the environment. The study highlights wastewater and environmental contamination as important but underrecognized drivers of antifungal resistance and calls for improved monitoring, regulation, and stewardship beyond clinical settings.