[Comparative sensitivity of yeasts to ketoconazole, itraconazole and fluconazole using a liquid medium standardized micromethod]

Abstract

The minimal inhibitory concentrations of 200 yeast strains (48 reference strains and 152 recently isolated from pathological products) were evaluated with a new standardized micromethod using a liquid medium comparatively for ketoconazole, itraconazole and fluconazole. The ready-to-use microtitration plates contained the antifungal agents in concentrations ranging from 100 to 0.10 mg/l. The cumulative MIC curves clearly showed the superiority of ketoconazole, fluconazole being the less active product. These results were confirmed after categorization in sensitive (S: MIC less than 0.78 mg/l), intermediate (I: 0.78 less than MIC less than 6.25) or resistant (R: MIC greater than 6.25). These results are discussed particularly for fluconazole showing the largest half-life and for which higher plasmatic levels could be achieved. Important variations were observed depending on the species and as example for Candida tropicalis the sensitivities were ketoconazole 100%, itraconazole 55% and fluconazole 0%. The less sensitive species to the 3 azoles were Saccharomyces cerevisiae and Torulopsis glabrata. This new micromethod being very easy to use and allowing the determination of fungicidal activities should be introduced in routine.