Miranda Isabela Lima, Peres Nalu Teixeira Aguiar, Bastos Rafael Wesley, Rossato Luana, Cruz Gabriela Silva, Azevedo Maria Isabel, Silva Kássia Jéssica Galdino, Castelo-Branco Débora S C M, Lucini Fabíola, Santos Daniel Assis
Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, 31270-901, MG, Brazil.
National Institute of Science and Technology in Human Pathogenic Fungi, Ribeirão Preto, Brazil.
Braz J Microbiol. 2025 Aug 22. doi: 10.1007/s42770-025-01766-y.
The resistance in Trichosporon species poses a significant challenge in clinical treatment, limiting the efficacy of commonly used antifungal drugs. In this context, T. asahii poses substantial risks as an opportunistic pathogen, especially in immunocompromised patients, where the effective antifungal treatment is also challenged by the absence of standardized testing methods. In this scenario, the present study evaluated and discussed the broth microdilution susceptibility testing of Trichosporon species to fluconazole and amphotericin B. A total of 33 Trichosporon spp. strains, isolated from different sources, along with reference strains, were tested. Different adaptations of the CLSI guidelines were applied to investigate optimal conditions for minimum inhibitory concentration (MIC) determination in this genus. The results revealed that fluconazole showed less variation between the tested incubation periods, with reading at 50% inhibition, while amphotericin B demonstrated more accurate results with extended incubation (48 h) and reading at 100% inhibition. Additionally, fluconazole exhibited higher MICs when isolates were incubated at 30 °C, with a range of 1-32 µg/mL, where amphotericin B showed higher MICs at 37 °C, with a range of 0.5-4 µg/mL. This work also reveals significant variability in susceptibility results, underscoring the necessity for standardized testing protocols. Based on the results, the study recommends for the optimal susceptibility testing a 48 h incubation period at 37 °C, with reading breakpoints of 50% inhibition for fluconazole and 100% inhibition for amphotericin B. Yet, this study highlights the urgent need for standardized testing methods and better understanding of antifungal resistance in Trichosporon infections.
毛孢子菌属的耐药性给临床治疗带来了重大挑战，限制了常用抗真菌药物的疗效。在这种情况下，阿萨希毛孢子菌作为一种机会性病原体构成了重大风险，尤其是在免疫功能低下的患者中，有效的抗真菌治疗还因缺乏标准化检测方法而受到挑战。在这种情况下，本研究评估并讨论了毛孢子菌属对氟康唑和两性霉素B的肉汤微量稀释药敏试验。共测试了33株从不同来源分离的毛孢子菌属菌株以及参考菌株。应用了不同的临床和实验室标准协会（CLSI）指南改编方法来研究该属中最低抑菌浓度（MIC）测定的最佳条件。结果显示，氟康唑在不同测试孵育期之间的差异较小，在抑制率为50%时读数，而两性霉素B在延长孵育（48小时）并在抑制率为100%时读数时显示出更准确的结果。此外，当分离株在30°C孵育时，氟康唑的MIC较高，范围为1 - 32μg/mL，而两性霉素B在37°C时显示出较高的MIC，范围为0.5 - 4μg/mL。这项工作还揭示了药敏结果存在显著差异，强调了标准化检测方案的必要性。基于这些结果，该研究建议进行最佳药敏试验时，在37°C孵育48小时，氟康唑的读数断点为抑制率50%，两性霉素B的读数断点为抑制率100%。然而，这项研究强调了迫切需要标准化检测方法以及更好地了解毛孢子菌感染中的抗真菌耐药性。
