Genome-wide expression profiling reveals genes associated with amphotericin B and fluconazole resistance in experimentally induced antifungal resistant isolates of Candida albicans

J Antimicrob Chemother. 2004 Aug;54(2):376-85. doi: 10.1093/jac/dkh336. Epub 2004 Jun 16.


Objectives: The aim of this study was to identify changes in the gene expression profile of Candida albicans associated with the acquisition of experimentally induced resistance to amphotericin B and fluconazole.

Methods: C. albicans SC5314 was passed in increasing concentrations of amphotericin B to generate isolate SC5314-AR. Susceptibility testing by Etest revealed SC5314-AR to be highly resistant to both amphotericin B and fluconazole. The gene expression profile of SC5314-AR was compared with that of SC5314 using DNA microarray analysis. Sterol composition was determined for both strains.

Results: Upon examination of MICs of antifungal compounds, it was found that SC5314-AR was resistant to both amphotericin B and fluconazole. By microarray analysis a total of 134 genes were found to be differentially expressed, that is up-regulated or down-regulated by at least 50%, in SC5314-AR. In addition to the cell stress genes DDR48 and RTA2, the ergosterol biosynthesis genes ERG5, ERG6 and ERG25 were up-regulated. Several histone genes, protein synthesis genes and energy generation genes were down-regulated. Sterol analysis revealed the prevalence of sterol intermediates eburicol and lanosterol in SC5314-AR, whereas ergosterol was the predominant sterol in SC5314.

Conclusion: Along with changes in expression of these ergosterol biosynthesis genes was the accumulation of sterol intermediates in the resistant strain, which would account for the decreased affinity of amphotericin B for membrane sterols and a decreased requirement for lanosterol demethylase activity in membrane sterol production. Furthermore, other genes are implicated as having a potential role in the polyene and azole antifungal resistant phenotype.

MeSH terms

  • Amphotericin B / pharmacology*
  • Antifungal Agents / pharmacology*
  • Candida albicans / drug effects*
  • Candida albicans / genetics*
  • Candidiasis / microbiology*
  • Cytochrome P-450 Enzyme System / pharmacology
  • DNA Primers
  • DNA, Complementary / biosynthesis
  • DNA, Complementary / genetics
  • Drug Resistance, Fungal
  • Ergosterol / biosynthesis
  • Ergosterol / genetics
  • Ergosterol / pharmacology
  • Fluconazole / pharmacology*
  • Gene Expression Profiling
  • Genes, Fungal / genetics*
  • Genome, Fungal
  • Humans
  • Microbial Sensitivity Tests
  • Oligonucleotide Array Sequence Analysis
  • Oxidoreductases / pharmacology
  • Phenotype
  • Protein Folding
  • RNA, Fungal / biosynthesis
  • RNA, Fungal / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / genetics
  • Sterol 14-Demethylase
  • Sterols / metabolism


  • Antifungal Agents
  • CYP51A1 protein, human
  • DNA Primers
  • DNA, Complementary
  • RNA, Fungal
  • Sterols
  • Amphotericin B
  • Fluconazole
  • Cytochrome P-450 Enzyme System
  • Oxidoreductases
  • Sterol 14-Demethylase
  • Ergosterol