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Azole resistance has emerged as a new therapeutic challenge in patients with aspergillosis. Various resistance mutations are attributed to the widespread use of triazole-based fungicides in agriculture. This study explored the prevalence of azole-resistant Aspergillus fumigatus (ARAF) and other aspergilli in the Argentine environment. A collection of A. fumigatus and other aspergilli strains isolated from soil of growing crops, compost, corn, different animal feedstuffs, and soybean and chickpea seeds were screened for azole resistance. No ARAF was detected in any of the environmental samples studied. However, five A. flavus, one A. ostianus, one A. niger and one A. tamarii recovered from soybean and chickpea seeds showed reduced susceptibility to medical azole antifungals (MAA). The susceptibility profiles of five A. flavus isolates, showing reduced susceptibility to demethylase inhibitors (DMIs), were compared with those of 10 isolates that exhibited susceptibility to MAA. Aspergillus flavus isolates that showed reduced MAA susceptibility exhibited different susceptibility profiles to DMIs. Prothioconazole and tebuconazole were the only DMIs significantly less active against isolates with reduced susceptibility to MAA. Although no ARAF isolates were found in the samples analysed, other aspergilli with reduced susceptibility profile to MAA being also important human pathogens causing allergic, chronic and invasive aspergillosis, are present in the environment in Argentina. Although a definitive link between triazole-based fungicide use and isolation of azole-resistant human pathogenic aspergilli from agricultural fields in Argentina remains elusive, this study unequivocally highlights the magnitude of the environmental spread of azole resistance among other Aspergillus species., (© The Author(s) 2024. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.)

Background: The emergence of azole resistance in non-fumigatus Aspergillus strains is on the raise., Objectives: To study the susceptibility profiles and the molecular mechanisms of azole resistance of environmental and clinical strains of Aspergillus flavus from Argentina., Methods: Thirty-five A flavus isolates (18 from soybean seeds and chickpea seeds and 17 from the clinic) were analysed for amphotericin B and azole resistance using the standard microbroth dilution method according to CLSI M38-A2 guidelines. Sequencing analysis of the cyp51 genes was conducted in those isolates displaying high MICs values to itraconazole, voriconazole and/or posaconazole., Results: Among the environmental isolates, 33.3% of them showed high MIC values for at least one triazole whereas 23.5% of the clinical isolates displayed high MIC values for amphotericin B. Point mutations in the Cyp51C gene were recorded in most environmental isolates with non-wild-type MIC values., Conclusions: Susceptibility differences among environmental A flavus isolates might suggest the possibility of native resistance to certain triazole antifungals used in the clinic. To the best of our knowledge, this is the first report of antifungal screening of environmental strains of A flavus in soybean seeds and chickpea seeds from Argentina that showed increased resistance to voriconazole and itraconazole in comparison to clinical strains., (© 2020 Wiley-VCH GmbH.)