Abstract:
Invasive fungal infections caused by opportunistic fungi such as Candida spp., Aspergillus spp., and Cryptococcus spp.
continue to be major causes of morbidity and mortality in spite of advancements in diagnostic tools and antifungal
treatments. Despite the tendency to broaden the therapeutic options in invasive fungal infections, the misuse of these
antifungals has led to the emergence of antifungal resistance. In this context, antifungal susceptibility testing (AFST)
plays a vital role in guiding treatment decisions, predicting clinical outcomes, detecting resistance, and mapping
epidemiological trends. Broth microdilution is the gold standard method for AFST, and both the Clinical Laboratory
Standards Institute (CLSI) and the European Committee on Antibiotic Susceptibility Testing (EUCAST) have
standardized this technique. Although the two organizations share several key practices, such as the use of RPMI-1640
broth medium and standardized incubation conditions, they also have critical differences in inoculum density, glucose
concentration, and MIC determination methods. These differences can influence the results, making reproducibility and
consistency in testing essential. AFST also plays a critical role in the development of new antifungal agents by assessing
their activity against various fungal strains. Given the growing concern of antifungal resistance, accurate and standardized
susceptibility testing remains crucial for effective treatment and the development of new therapies.
