Aspergillus fumigatus is ubiquitous in the environment and is an opportunistic human pathogen affecting immunocompromised individuals and those with lung diseases. Cross-resistance between agricultural fungicides and medical antifungals has raised concerns, as some agricultural fungicide active ingredients may exhibit activity against A. fumigatus and potentially select for antifungal resistance. [SN1] In 2024, the U.S. EPA finalized a framework to assess potential adverse impacts of pesticides on the efficacy of human and animal antibacterial and antifungal pharmaceuticals. The framework is designed to recognize the benefits of these pesticides to agriculture and minimize their impact on public health, whilst considering the goals of the One Health approach.
FDA’s Guidance for Industry (GFI)[SN2] #152 draft guidance for antimicrobial drug resistance offers a qualitative framework. EPA’s 2024 framework proposed to apply this for antibacterial pesticides. However, the FDA’s GFI #152 cannot be applied to assess the risk of antifungal resistance (AFR) development in human pathogens from the agricultural use of fungicides. A. fumigatus generally thrives in decaying plant matter. Some environments that support A. fumigatus growth may be termed ‘hotspots’, posing a higher risk for development of AFR than other environments, termed ‘coldspots’. Detection of A. fumigatus may not be appropriate to designate an environment as a hotspot or cold spot without considering the impact of the residue levels of the fungicide in growing substrate and environmental conditions on the fungal growth and reproductive potential of the fungal pathogen. The complex interplay of multiple factors simultaneously influencing the growth and reproduction of A.fumigatus, necessitates a more sophisticated approach. Hence a dynamic model is needed to adequately represent the environmental conditions[SN3], quantify the emergence and selection of resistance, assess the effectiveness of mitigation measures, and evaluate alternative practices aimed at reducing the risk of AFR.
This poster will present a dynamic model built upon a mechanistic model published by Paveley et al., 2025 (Plant Pathology 74: 578-594) to quantify the growth and reproduction of resistant and wild-type A. fumigatus, the conditions that impact the selection of resistant strains, and evaluate the effectiveness of mitigation measures.

Yaoxing Wu

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