CHROMAgar Candida más fluconazol: comparación con técnicas de microdilución

Abstract

The increasing incidence of fungal infections and the reported emergence of resistance to antifungal agents call for the development of techniques for in vitro measurement of antifungal susceptibility that will enable prediction of clinical outcome in patients suffering from these infections. METHODS. Susceptibility to fluconazole was tested in 156 clinical yeast isolates (109, Candida albicans; 19, C. parapsilosis; 12, C. glabrata; 11, C. tropicalis; 2, C. krusei; 1, C. pelliculosa; 1, C. lambica, and 1, Saccharomyces cerevisiae) and two control strains (C. krusei ATCC 6258 and C. parapsilosis ATCC 22019) using a simple screening method, CHROMAgar Candida with fluconazole (8 micro g/ml). This method was compared with two broth microdilution techniques: the reference method (NCCLS, document M27-A) and Sensititre(TM) YeastOne. Sensititre(TM) YeastOne showed close agreement with NCCLS M27-A results for all species (C. albicans and non albicans). CHROMAgar Candida with fluconazole (8 micro g/ml) yielded results matching those of the two broth microdilution methods for sensitive strains and strains highly resistant to fluconazole (C. krusei and C. glabrata), but performed less well with strains displaying dose-dependent susceptibility. These data suggest that CHROMAgar Candida with fluconazole (8 micro g/ml), appears to be a rapid, simple and sensitive screening method for detection and identification of fluconazole-susceptible and -highly resistant yeasts. However, additional methods should be used to determine whether positive growth in this medium is due to resistant strains (MIC > or = 64 micro g/ml) or to strains displaying dose-dependent susceptibility (MIC 16-32 micro g/ml). The usefulness of CHROMAgar Candida with fluconazole depends on the sample source and the species under study.