Background: Invasive fungal infections are associated with high morbidity and mortality, often necessitating fast-acting treatment. While until recently amphotericin B was the only antifungal available to treat these serious infections, less toxic lipid formulations of amphotericin B, including Abelcet and AmBisome, have since been developed. MIC data obtained from a multicenter study in 2000 showed that Abelcet demonstrated more activity against Candida spp. than AmBisome, and it was theorized that this might be due to the earlier release of amphotericin B from the formulation. In order to compare the rate at which Abelcet and AmBisome release amphotericin B, time-kill curves were determined against 2 representative C. albicans strains. Special attention was paid to time points immediately following drug exposure. Methods: One fluconazole-susceptible and one fluconazole-resistant C. albicans strain were tested in a time-kill assay comparing Abelcet to AmBisome. Isolates were exposed to concentrations of antifungal at 0.5 MIC and 1 MIC (determined according to the CLSI M27A2 standard), and viable cell counts were performed at 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 12, 24, and 36 hours. Results: Exposure of both the fluconazole-susceptible and fluconazole-resistant C. albicans isolates to Abelcet resulted in complete kill within 4 hours at 1 MIC, as opposed to 8 hours with AmBisome at 1 MIC. Conclusion: Our data shows that Abelcet begins killing C. albicans at an earlier time point than AmBisome, which may indicate a distinct clinical advantage in the treatment of serious invasive fungal infections. In vivo validation of this data is warranted.
Full conference title:
Infectious Diseases Society of America, 44th Annual Meeting
- IDSA 44th