MALDI-TOF MS-Based Clustering and Antifungal Susceptibility Tests of Talaromyces marneffei Isolates from Fujian and Guangxi (China)

INTRODUCTION: Talaromyces marneffei is a life-threatening pathogen that causes systemic talaromycosis in immunocompromised and acquired immunodeficiency syndrome (AIDS) patients. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) as a tool to cluster T. marneffei isolates is rarely reported and the data on antifungal susceptibility of T. marneffei isolated in the southern region of China, especially in Fujian, is hardly found. METHODS: MALDI-TOF MS was used to cluster 135 T. marneffei isolates, and the minimum inhibitory concentration (MIC) values of amphotericin B, itraconazole, posaconazole, voriconazole, fluconazole, anidulafungin, micafungin, caspofungin and 5-fluorocytosine with Sensititre YeastOne™ YO10 assay were measured during January 2017 to October 2020 in Fujian and Guangxi. RESULTS: MALDI-TOF MS correctly identified 100% of the T. marneffei isolates. Hierarchical clustering of MALDI-TOF peak profiles identified four different clusters. MICs for itraconazole, posaconazole, voriconazole and amphotericin B were as follows: ≤0.015–0.03 μg/mL, ≤0.008–0.03 μg/mL, ≤0.008–0.06 μg/mL, ≤0.12–1 μg/mL, respectively. MICs for echinocandins and fluconazole were comparatively high. CONCLUSION: Since only simple sample preparation is required and since results are available in a short period of time, MALDI-TOF MS can be considered as a method for identification and clustering of T. marneffei. Itraconazole, posaconazole, voriconazole and amphotericin B can be used to treat T. marneffei infected patients due to the low MICs.