INFLUENCE OF HUMAN SERUM ON THE POSTANTIFUNGAL EFFECT OF 4 ANTIFUNGALAGENTS ON CANDIDA-ALBICANS

This study evaluates the influence of both fresh and heated human seru m on the postantifungal effect (PAFE) induced by different concentrati ons of amphotericin B (AmB), 5-fluorocytosine (5-Fc), Ketoconazole (Kz ) and fluconazole (Flu) on two strains of Candida albicans. The concen trations were selected in harmony with the pharmacokinetic properties and toxicity of the drugs. Without serum there was no delay in the gro wth of yeast cultures pretreated with Kz or Flu, leading to negative P AFEs, however with AmB and 5-Fc the PAFEs were positive. When assays w ere made in the presence of 10% fresh human serum, the duration of the PAFEs increased with all drugs tested, and those induced by azolic ag ents became positive. In the presence of 10% human serum heated at 56 degrees C for 30 min, the PAFEs of the antifungal agents were similar to those obtained in the absence of serum. Our results suggest that fr esh serum positively influenced PAFE which may be an important factor in determining the dosing regimen for infection by yeasts.