Candida albicans Mutations in the Ergosterol Biosynthetic Pathway and Resistance to Several Antifungal Agents

作者：Dominique Sanglard, Françoise Ischer, Tania Parkinson, Derek J. Falconer, Jacques Billé · 发表于：Antimicrobial Agents and Chemotherapy · 年份：2003 · DOI：10.1128/aac.47.8.2404-2412.2003 · 被引用次数：407 · 研究领域：Antifungal resistance and susceptibility、Probiotics and Fermented Foods、Herbal Medicine Research Studies

The role of sterol mutations in the resistance of Candida albicans to antifungal agents has not been thoroughly investigated. Previous work reported that clinical C. albicans strains resistant to both azole antifungals and amphotericin B were defective in ERG3, a gene encoding sterol Delta(5,6)-desaturase. It is also believed that a deletion of the lanosterol 14alpha-demethylase gene, ERG11, is possible only under aerobic conditions when ERG3 is not functional. We tested these hypotheses by creating mutants by targeted deletion of the ERG3 and ERG11 genes and subjecting those mutants to antifungal susceptibility testing and sterol analysis. The homozygous erg3/erg3 mutant created, DSY1751, was resistant to azole derivatives, as expected. This mutant was, however, slightly more susceptible to amphotericin B than the parent wild type. It was possible to generate erg11/erg11 mutants in the DSY1751 background but also, surprisingly, in the background of a wild-type isolate with functional ERG3 alleles under aerobic conditions. This mutant (DSY1769) was obtained by exposure of an ERG11/erg11 heterozygous strain in a medium containing 10 micro g of amphotericin B per ml. Amphotericin B-resistant strains were obtained only from ERG11/erg11 heterozygotes at a frequency of approximately 5 x 10(-5) to 7 x 10(-5), which was consistent with mitotic recombination between the first disrupted erg11 allele and the other remaining functional ERG11 allele. DSY1769 was also resistant to azole d...