In vitro anti-Cryptococcus activity of diphenyl diselenide alone and in combination with amphotericin B and fluconazole

Cryptococcus is an encapsulated yeast that causes fungal meningitis, most commonly in HIV patients, with high mortality rates. Thus, the study of new treatment options is relevant. Antifungal activity of organoselenium compounds attributed to their pro-oxidative effect in fungal cells has been shown given that few data regarding its anti- Cryptococcus activity are available, this in vitro study was conducted with 40 clinical isolates of Cryptococcus neoformans. Diphenyl diselenide (DD) alone, and its interaction with amphotericin B or fluconazole, was tested by microdilution and checkerboard assays. All Cryptococcus neoformans were inhibited by DD in concentrations ≤ 32 μg/mL, and fungicidal concentrations were ≤ 64 μg/mL. Advantageous interaction between fluconazole occurred in 40% of the isolates, respectively. This study contributes with data of DD alone and in combination with classical drugs of choice for cryptococcosis treatment. Further studies focused on DD antifungal mechanism of action, and in vivo experiments are necessary.