Doubling of triazole resistance rates in invasive aspergillosis over a 10-year period, Belgium, 1 April 2022 to 31 March 2023

This study reveals that resistance rates in Aspergillus fumigatus have doubled in Belgium over a decade, from 4.6% in 2011 to 9.7% in 2022-2023. This doubled rate is almost reached, requiring a re-evaluation of antifungal therapy regimens. Geographical differences in resistance rates were also observed, with even rates exceeding 10% in densely populated provinces. The findings highlight the need for sustained and long-term resistance surveillance data to guide treatment decisions and improve antifungal resistance detection in clinical practice.