Postantifungal Effect of Older and Newer Antifungal Agents on Aspergillus fumigatus and Candida albicans

M. S. RAMESH, I. BASKARAN, L. T. GANESAN, E. K. MANAVATHU, P. H. CHANDRASEKAR

Author address: 

Wayne State University, Detroit, MI.

Abstract: 

The postantifungal effect (PAFE) of a compound is defined as the time required for the organism to recover from the crippling injury sustained by the fungal cell as a result of a brief exposure to the compound. The PAFE is usually evaluated by the ability of the cells to grow and multiply following short exposure to the antifungal drug as determined by the CFU/ml of culture. Since no reliable method is currently available for the determination of CFU/unit volume of culture, we examined the PAFE of various antifungal agents on A. fumigatus by a radiometric assay where fungal growth was measured by 14C-amino acids incorporation by the mycelia. The results thus obtained for A. fumigatus was compared with those obtained for C. albicans as determined by CFU/ml of cultures. A. fumigatus cultures pregrown (48 h) in 96-well microtiter plate were exposed to various concentrations of the antifungal agent for 2 h. The drug-treated mycelia were washed with and incubated in RPMI 1640 (0.2 ml) containing 14C-amino acids. The incorporation of 14C-amino acids by the mycelia at various time intervals was determined by scintillation counting. The PAFE was determined by plotting the amount of radioactivity associated with the mycelia vs. time of incubation. Among various antifungal agents tested against A. fumigatus, amphotericin B (AMB) produced a prolonged PAFE (6 h) whereas itraconazole, voriconazole, posaconazole and ravuconazole (≤ 30 min) and the echinocandin caspofungin (
2001

abstract No: 

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Full conference title: 

ICAAC 41st
    • ICAAC 41st