Antifungal drug combinations for Cryptococcus neoformans and Prototheca spp.

Seventy-one isolates of Cryptococcus neoformans and 5 isolates of Prototheca spp. were tested for in vitro susceptibility against amphotericin B alone and against the combination of amphotericin B with each clinically relevant concentration of flucytosine (5-FC) and rifampin by broth dilution methods. The combinations of amphotericin B and rifampin produced greater effect on reduction of the minimal inhibition concentration (MIC) of amphotericin B than did either drug used individually. Flucytosine combined with amphotericin B produced little or no reduction of the MIC compared with amphotericin B alone.