Phenotypic variation and antifungal susceptibility patterns of Candida albicans strains isolated from neutropenic patients

The aim of this study was to investigate the relationship between phenotype s of Candida albicans strains isolated from clinical specimens and the susc eptibility of the strains to three antifungal agents, fluconazole, amphoter icin B and flucytosine. Oropharyngeal, gastrointestinal and urogenital trac t specimens were collected from 122 neutropenic patients who had received n o previous prophylactic treatment. Each of 122 C. albicans strains recovere d was found to express one of the six phenotypes: smooth, fuzzy, irregular, star, ring and stipple. The mean minimum inhibitory concentrations (MICs) of fluconazole was consistently higher for C. albicans strains expressing t he stipple phenotype. The mean MICs for the six phenotypes of C. albicans s trains ranged between 1.22 and 7.94 mu g ml(-1) for fluconazole, 0.99 and 2 .55 mu g ml(-1) for amphotericin B and 1.23 and 1.83 mu g ml(-1) for flucyt osine. The antifungal susceptibility of the stipple phenotype requires atte ntion, especially in patients who are clinically unresponsive to fluconazol e chemotherapy or in cases of life-threatening C. albicans infections of im munocompromised hosts. Long-term use of fluconazole may explain the outcome of the resistant stipple phenotype.