S5.4d Agrochemicals potentiate multidrug resistance and alter virulence in Cryptococcus neoformans via hitch-hiking effect of aneuploidy

S5.4 FREE ORAL PAPER SESSION, SEPTEMBER 22, 2022, 3:00 PM - 4:30 PM: OBJECTIVES: Cryptococcus neoformans is an environmental fungal pathogen causing fatal pulmonary and disseminated infections in humans, especially in AIDS patients. However, only three antifungal drugs are available for the treatment of cryptococcosis: fluconazole, amphotericin B, and flucytosine. C. neoformans is worldwide distributed in nature, but environmental factors influencing antifungal drug susceptibility are largely unknown. METHODS: We tested the antifungal effect of agrochemicals against C. neoformans lab strain H99. We obtained drug-resistant adaptors. We sequenced the adaptors and got a list of adaptors bearing unique aneuploidy. We asked if aneuploidy caused multidrug resistance to antifungal drugs and if aneuploidy altered virulence in vitro and in vivo. We also investigated the molecular mechanism of aneuploidy-mediated multidrug resistance. RESULTS: Here we found tebuconazole and benomyl, belonging to two distinct classes of agrochemicals, could inhibit the growth of H99. However, H99 could gain resistance to both drugs mainly via aneuploidy. Importantly, particular aneuploidy also caused multidrug resistance to fluconazole, amphotericin B, and flucytosine. Furthermore, aneuploidy also altered virulence in vitro and in vivo. We found copy number variation of genes on the aneuploid chromosome caused a proportional increase in transcript and protein levels. CONCLUSION: Therefore, we posit agrochemicals could enhance multidrug resistance and alter the virulence of C. neoformans via the hitch-hiking effect of aneuploidy.