Authors: Dieste-Pérez Lucía, Holstege Manon M C, de Jong Judith E, Heuvelink Annet E
Journal: Frontiers in veterinary science
Summary
# Editorial Summary: Azole Resistance in Aspergillus Species from Animals — A Growing Concern Azole antifungals are critical treatments for aspergillosis across equine and companion animal practice, yet emerging resistance in *Aspergillus* populations poses a significant therapeutic challenge. Dieste-Pérez and colleagues conducted a systematic review of 73 peer-reviewed articles (2013–2024) examining azole resistance in *Aspergillus* isolates from animals and their environments, extracting minimum inhibitory concentration (MIC) data and clinical outcomes from both descriptive cases and in-vitro susceptibility studies. Clinical cases predominantly involved horses, dogs, cats, zoo animals and wildlife, with successful treatment generally requiring prolonged continuous azole therapy; itraconazole dominated equine and companion animal protocols whilst voriconazole was preferred for zoo and wild species. Critically, non-wild-type (resistant) *A. fumigatus* and *A. flavus* isolates were identified across all animal categories on multiple continents, with zoo animals, wildlife, horses and poultry presenting the highest prevalence concern—findings that warrant heightened clinical vigilance regarding azole efficacy and potential treatment failures in these populations. The authors highlight a significant evidence gap: European data remain insufficient for robust regional conclusions, underscoring an urgent need for standardised, comparable resistance surveillance protocols across veterinary settings to inform rational antifungal stewardship in equine and small animal medicine.
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Practical Takeaways
- •Equine practitioners should be aware that azole-resistant Aspergillus infections occur in horses and may require prolonged antifungal therapy; culture and susceptibility testing are important before treatment initiation
- •Horses, zoo animals, wildlife, and poultry represent higher-risk categories for azole-resistant Aspergillus isolates, suggesting environmental and management factors may play a role in resistance development
- •Current data gaps, particularly for Europe, mean practitioners should maintain detailed clinical records and consider contributing to systematic surveillance efforts to better understand resistance patterns in their regions
Key Findings
- •Non-wild type (NWT) azole-resistant A. fumigatus and A. flavus isolates were identified across multiple animal categories including horses, companion animals, zoo animals, wildlife, and poultry, in both Europe and beyond
- •Zoo animals, wildlife, horses, and poultry showed the highest prevalence of NWT A. fumigatus and A. flavus isolates compared to other animal categories
- •Itraconazole was the most frequently used azole treatment in clinical cases involving horses and companion animals, with successful clinical remission typically requiring prolonged and continuous treatment
- •MIC50 values for itraconazole were lowest in A. fumigatus isolates from companion animals, while voriconazole showed similar or slightly lower MIC50 values in zoo animals and wildlife compared to other categories