Brief Original Article

Background: Resistance to antifungal drugs, especially towards triazoles, is commonly referred to by clinicians, but data on its prevalence in developing countries is limited. Methodology: To determine the prevalence of triazole-resistance amongst pathogenic yeasts and moulds, we assessed the in vitro susceptibility of 250 isolates from hospitalized patients at five Mexican cities towards amphotericin B, fluconazole and voriconazole, by Etest. Results: All yeasts were susceptible to voriconazole, according to E-test interpretive criteria (MIC ≤ 1 μg/mL), and all filamentous or dimorphic fungi also had voriconazole MIC ≤ 1 μg/mL, except for one isolate each of Mucor sp. and Acremonium sp. Candida krusei and one isolate of C. glabrata were resistant to fluconazole, a drug that had MIC ≥ 192 μg/mL for filamentous fungi. Although no breakpoints for amphotericin B are available, all three C. krusei, 2/25 C. glabrata, 3/22 C. parapsilosis and 1/108 C. albicans had MIC ≥ 2 μg/mL. Conclusion: In vitro, voriconazole is active against yeasts and moulds commonly causing severe mycoses in Mexico.