Antifungal susceptibility of emerging yeast pathogens

BACKGROUND. To study the antifungal susceptibility of emerging yeast pathogens to know their possible resistance under the need of applying a treatment. MATERIAL AND METHODS. We investigated the in vitro susceptibility of 69 yeast strains isolates of clinical samples, belonging to 24 different species, to amphotericin B, fluconazole, itraconazole, ketoconazole and 5-fluorocytosine. RESULTS. Only 9 species showed susceptibility to all antifungal agents: Candida famata, C. guillermondii, C. holmii, C. kefyr, C. pelliculosa, C. rugosa, C. utilis, C. zeylanoides y Trichosporon cutaneum; the rest of them presented resistance to some antifungal agent. C. haemulonii; Pichia farinosa and Trichosporon mucoides were resistant to amphotericin B; C. haemulonii, C. inconspicua, C. lusitaniae, C. norvegensis, C. pintolepesii, C. valida, P. ohmeri, Rhodotorula glutinis, R. minuta, R. mucilaginosa and Saccharomyces cerevisiae were resistant to azoles; Blastoschizomyces capitatus and C. lipolytica were resistant to 5-fluorocytosine. CONCLUSIONS. The resistance of emerging yeast pathogens to amphotericin B and 5-fluorocytosine is low, while resistance to azoles is significative, especially to fluconazole (36%). Many of this yeasts present problems of intrinsic resistance. In yeast infections, the correct identification of species and the study of the in vitro susceptibility is important in order to choose the most adequate antifungal treatment.