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

ABSTRACT

The aim of this study was to investigate the relationship between phenotypes of Candida albicans strains isolated from clinical specimens and the susceptibility of the strains to three antifungal agents, fluconazole, amphotericin B and flucytosine. Oropharyngeal, gastrointestinal and urogenital tract specimens were collected from 122 neutropenic patients who had received no previous prophylactic treatment. Each of 122 C. albicans strains recovered 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 the stipple phenotype. The mean MICs for the six phenotypes of C. albicans strains ranged between 1.22 and 7.94 micrograms ml-1 for fluconazole, 0.99 and 2.55 micrograms ml-1 for amphotericin B and 1.23 and 1.83 micrograms ml-1 for flucytosine. The antifungal susceptibility of the stipple phenotype requires attention, especially in patients who are clinically unresponsive to fluconazole chemotherapy or in cases of life-threatening C. albicans infections of immunocompromised hosts. Long-term use of fluconazole may explain the outcome of the resistant stipple phenotype.