Antifungal Susceptibility and Genotypic Analysis of Mutations in Isolates in Malaysia.

Purpose: Azole resistance in poses a significant challenge in the management of invasive aspergillosis. This study aimed to investigate the antifungal susceptibility and mutation profiles of isolates in Malaysia.

Patients And Methods: Sixty clinical isolates were collected and subjected to antifungal susceptibility testing (AFST) and molecular analysis. The antifungal susceptibility testing was performed according to CLSI M38 guideline. The geometric mean (GM) minimum inhibitory concentration (MIC), MIC/MIC for voriconazole, itraconazole, posaconazole, amphotericin B, and isavuconazole against in non-invasive cases and invasive cases were calculated. In addition, the presence of mutations was also identified.

Results: The present study revealed an overall resistance rate of 6.7% among the isolates. In non-invasive cases, isavuconazole and posaconazole demonstrated the lowest GM MIC of 0.08 µg/mL. Following them were itraconazole, voriconazole, and amphotericin B with concentrations of 0.15µg/mL, 0.16µg/mL and 0.90µg/mL, respectively. Similarly, in invasive cases, isavuconazole and posaconazole exhibited the lowest GM MIC of 0.09µg/mL. Following them were itraconazole, voriconazole, and amphotericin B with concentrations of 0.14µg/mL, 0.17µg/mL and 0.80µg/mL, respectively. Genotypic analysis revealed various mutations, including F46Y, M172V, N248K, R34L, V244A, V244S, and E427K. However, not all mutations corresponded to antifungal resistance.

Conclusion: The majority of clinical isolates demonstrated susceptibility to the antifungal agents tested, with isavuconazole and posaconazole demonstrating the lowest MIC values. However, mutations were discovered without a consistent correlation to antifungal resistance, emphasising the need for additional research.