Objective To observe antifungal effects of thiabendazole combined with fluconazole, amphotericin B, posaconazole, itraconazole and voriconazole, respectively on Cryptococcus neoformans in vitro.

Methods The minimum inhibitory concentrations (MIC) of the chemical agents against 20 strains of Cryptococcus neoformans by thiabendazole and antifungal agents including fluconazole, amphotericin B, posaconazole, itraconazole and voriconazole alone were determined according to the M27-A3 protocol proposed by the American Clinical Laboratory Standardization Committee. Microdilution checkerboard technique system was used to determine in vitro antifungal effects of thiabendazole in combination with fluconazole, amphotericin B, posaconazole, itraconazole or voriconazole, respectively for 20 strains of Cryptococcus neoformans.

Results MIC of thiabendazole against Cryptococcus neoformans ranged from 8 to 32 μg/mL. MICs of amphotericin B, fluconazole, itraconazole, posaconazole and voriconazole against Cryptococcus neoformants were 0.250 0 to 8.000 0, 1.000 0 to 8.000 0, 0.062 5 to 2.000 0, 0.062 5 to 4.000 0 and 0.062 5 to 1.000 0 μg/mL, respectively. Synergistic inhibitory effect was found in 7 strains via thiabendazole and amphotericin B, 8 strains via thiabendazole and fluconazole, 4 strains via thiabendazole and itraconazole, 5 strains via thiabendazole and posaconazole, and 1 strain via thiabendazole and voriconazole, respectively.

Conclusion Thiabendazole has potential anti-Cryptococcus neoformans effect and have synergy effects in combination with antifungal agents such as fluconazole, amphotericin B, posaconazole, itraconazole, voriconazole against Cryptococcus neoformans, which can decrease MIC of antifungal drugs against some strains of Cryptococcus neoformans.