SACCHAROMYCES CEVEVISIAE INFECTIONS AND ANTIFUNGAL SUSCEPTIBILITY STUDIES BY COLORIMETRIC AND BROTH MACRODILUTION METHODS

Saccharomyces cerevisiae was isolated in large numbers from operative specimens from two patients with perforated bowel and peritonitis and from the blood of another patient treated with extracorporeal membrane oxygenation. Susceptibility studies were performed on these three iso lates and another 29 isolates that colonized or caused infection in a total of 19 patients seen over the last decade. All isolates had low m inimum inhibitory concentration (MIC) values for amphotericin B (MIC(9 0) of less than or equal to 0.02 mu g/ml) and flucytosine (MIC(90) of 0.2 mu g/ ml), and a broader range of MIC values for itraconazole (MIC (90) of 0.8 mu g/ml) and fluconazole (MIC(90) of 4 mu g/ml). A colorim etric method using Alamar blue reagent showed good concordance with th e standard broth macrodilution method for amphotericin B, flucytosine, and fluconazole, but less good concordance for itraconazole. Serious infections with S. cerevisiae probably should be treated with amphoter icin B, with or without the addition of flucytosine.