Susceptibility of Mexican isolates of yeasts and moulds to amphotericin B and triazole antifungals

Abstract

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 E-test. 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.