Postantifungal effects of echinocandin, azole, and polyene antifungal agents against Candida albicans and Cryptococcus neoformans

The postantifungal effect (PAFE) of fluconazole, MK-0991, LY303366, and amp hotericin B was determined against isolates of Candida albicans and Cryptoc occus neoformans. Concentrations ranging from 0.125 to 4 times the MIC were tested following exposure to the antifungal for 0.25 to 1 h. Combinations of azole and echinocandin antifungals (MK-0991 and LY303366) were tested ag ainst C. neoformans. Fluconazole displayed no measurable PAFE against Candi da albicans or Cryptococcus neoformans, either alone or in combination with either echinocandin antifungal. MK-0991, LY303366, and amphotericin B disp layed a prolonged PAFE of greater than 12 h against Candida spp. when teste d at concentrations above the MIC for the organism and 0 to 2 h when tested at concentrations below the MIC for the organism.