Comparison of in vitro Susceptibilities of in Mold and Yeast Forms in Malaysia.

Purpose: This study was aimed to determine minimum inhibitory concentration (MIC) differences between yeast and mold forms of in Malaysia.

Patients And Methods: Ninety-seven clinical strains of were received from various Malaysian hospitals from the year 2020 until 2022. Their identities were determined using microscopic, macroscopic and molecular methods. Next, the susceptibility of yeast and mold forms of each isolate against amphotericin B, itraconazole, voriconazole, posaconazole, ketoconazole, isavuconazole, terbinafine, caspofungin and micafungin were tested according to the broth microdilution according to the Clinical and Laboratory Standards Institute (CLSI) M38 and M27 guidelines. The geometric means of minimal inhibitory concentration (GM MIC), MIC, and MIC were determined for each antifungal. Additionally, Wilcoxon signed-rank test was used to compare the significant difference of GM MICs for each antifungal, GM MIC, MIC and MIC for the combined nine antifungals against different growth forms of . The significance was set at <0.05.

Results: Micafungin had the highest GM MIC, MIC and MIC for mold form of . For yeast form, amphotericin B achieved the highest GM MIC and MIC while micafungin achieved the highest MIC. However, the GM MIC, MIC and MIC of terbinafine and azole antifungals on were similar to each other, namely between 0.03 and 0.60µg/mL. The difference of GM MIC of all tested antifungals except caspofungin and micafungin was insignificant. Overall, GM MIC, MIC and MIC of the combined nine antifungals against two growth forms were insignificant.

Conclusion: The findings suggested either yeast or mold form can be used in the susceptibility testing of against amphotericin B, itraconazole, voriconazole, posaconazole, ketoconazole, isavuconazole and terbinafine.