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Antimicrob Agents Chemother. Jul 1997; 41(7): 1488–1494.
PMCID: PMC163945

The presence of an R467K amino acid substitution and loss of allelic variation correlate with an azole-resistant lanosterol 14alpha demethylase in Candida albicans.

Abstract

Azole resistance in the pathogenic yeast Candida albicans is an emerging problem in the human immunodeficiency virus (HIV)-infected population. The target enzyme of the azole drugs is lanosterol 14alpha demethylase (Erg16p), a cytochrome P-450 enzyme in the biosynthetic pathway of ergosterol. Biochemical analysis demonstrates that Erg16p became less susceptible to fluconazole in isolate 13 in a series of isolates from an HIV-infected patient. PCR-single-strand conformation polymorphism (PCR-SSCP) analysis was used to scan for genomic alterations of ERG16 in the isolates that would cause this change in the enzyme in isolate 13. Alterations near the 3' end of the gene that were identified by PCR-SSCP were confirmed by DNA sequencing. A single amino acid substitution (R467K) that occurred in isolate 13 was identified in both alleles of ERG16. Allelic differences within the ERG16 gene, in the ERG16 promoter, and in the downstream THR1 gene were eliminated in isolate 13. The loss of allelic variation in this region of the genome is most likely the result of mitotic recombination or gene conversion. The R467K mutation and loss of allelic variation that occur in isolate 13 are likely responsible for the azole-resistant enzyme activity seen in this and subsequent isolates. The description of R467K represents the first point mutation to be identified within ERG16 of a clinical isolate of C. albicans that alters the fluconazole sensitivity of the enzyme.

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Selected References

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  • Albertson GD, Niimi M, Cannon RD, Jenkinson HF. Multiple efflux mechanisms are involved in Candida albicans fluconazole resistance. Antimicrob Agents Chemother. 1996 Dec;40(12):2835–2841. [PMC free article] [PubMed]
  • Barrett-Bee KJ, Lane AC, Turner RW. The mode of antifungal action of tolnaftate. J Med Vet Mycol. 1986 Apr;24(2):155–160. [PubMed]
  • Borst P. Genetic mechanisms of drug resistance. A review. Acta Oncol. 1991;30(1):87–105. [PubMed]
  • Burgener-Kairuz P, Zuber JP, Jaunin P, Buchman TG, Bille J, Rossier M. Rapid detection and identification of Candida albicans and Torulopsis (Candida) glabrata in clinical specimens by species-specific nested PCR amplification of a cytochrome P-450 lanosterol-alpha-demethylase (L1A1) gene fragment. J Clin Microbiol. 1994 Aug;32(8):1902–1907. [PMC free article] [PubMed]
  • Chen C, Turi TG, Sanglard D, Loper JC. Isolation of the Candida tropicalis gene for P450 lanosterol demethylase and its expression in Saccharomyces cerevisiae. Biochem Biophys Res Commun. 1987 Aug 14;146(3):1311–1317. [PubMed]
  • Clark FS, Parkinson T, Hitchcock CA, Gow NA. Correlation between rhodamine 123 accumulation and azole sensitivity in Candida species: possible role for drug efflux in drug resistance. Antimicrob Agents Chemother. 1996 Feb;40(2):419–425. [PMC free article] [PubMed]
  • Hitchcock CA. Resistance of Candida albicans to azole antifungal agents. Biochem Soc Trans. 1993 Nov;21(4):1039–1047. [PubMed]
  • Hitchcock CA, Dickinson K, Brown SB, Evans EG, Adams DJ. Interaction of azole antifungal antibiotics with cytochrome P-450-dependent 14 alpha-sterol demethylase purified from Candida albicans. Biochem J. 1990 Mar 1;266(2):475–480. [PMC free article] [PubMed]
  • Ishida N, Aoyama Y, Hatanaka R, Oyama Y, Imajo S, Ishiguro M, Oshima T, Nakazato H, Noguchi T, Maitra US, et al. A single amino acid substitution converts cytochrome P450(14DM) to an inactive form, cytochrome P450SG1: complete primary structures deduced from cloned DNAS. Biochem Biophys Res Commun. 1988 Aug 30;155(1):317–323. [PubMed]
  • Kenna S, Bligh HF, Watson PF, Kelly SL. Genetic and physiological analysis of azole sensitivity in Saccharomyces cerevisiae. J Med Vet Mycol. 1989;27(6):397–406. [PubMed]
  • Kirsch DR, Lai MH, O'Sullivan J. Isolation of the gene for cytochrome P450L1A1 (lanosterol 14 alpha-demethylase) from Candida albicans. Gene. 1988 Sep 7;68(2):229–237. [PubMed]
  • Köhler GA, White TC, Agabian N. Overexpression of a cloned IMP dehydrogenase gene of Candida albicans confers resistance to the specific inhibitor mycophenolic acid. J Bacteriol. 1997 Apr;179(7):2331–2338. [PMC free article] [PubMed]
  • Lai MH, Kirsch DR. Nucleotide sequence of cytochrome P450 L1A1 (lanosterol 14 alpha-demethylase) from Candida albicans. Nucleic Acids Res. 1989 Jan 25;17(2):804–804. [PMC free article] [PubMed]
  • Lamb DC, Kelly DE, Schunck WH, Shyadehi AZ, Akhtar M, Lowe DJ, Baldwin BC, Kelly SL. The mutation T315A in Candida albicans sterol 14alpha-demethylase causes reduced enzyme activity and fluconazole resistance through reduced affinity. J Biol Chem. 1997 Feb 28;272(9):5682–5688. [PubMed]
  • Law D, Moore CB, Wardle HM, Ganguli LA, Keaney MG, Denning DW. High prevalence of antifungal resistance in Candida spp. from patients with AIDS. J Antimicrob Chemother. 1994 Nov;34(5):659–668. [PubMed]
  • Marriott MS. Inhibition of sterol biosynthesis in Candida albicans by imidazole-containing antifungals. J Gen Microbiol. 1980 Mar;117(1):253–255. [PubMed]
  • Parkinson T, Falconer DJ, Hitchcock CA. Fluconazole resistance due to energy-dependent drug efflux in Candida glabrata. Antimicrob Agents Chemother. 1995 Aug;39(8):1696–1699. [PMC free article] [PubMed]
  • Pfaller MA, Rhine-Chalberg J, Redding SW, Smith J, Farinacci G, Fothergill AW, Rinaldi MG. Variations in fluconazole susceptibility and electrophoretic karyotype among oral isolates of Candida albicans from patients with AIDS and oral candidiasis. J Clin Microbiol. 1994 Jan;32(1):59–64. [PMC free article] [PubMed]
  • Porter TD. Mutagenesis at a highly conserved phenylalanine in cytochrome P450 2E1 affects heme incorporation and catalytic activity. Biochemistry. 1994 May 17;33(19):5942–5946. [PubMed]
  • Poulos TL. Cytochrome P450: molecular architecture, mechanism, and prospects for rational inhibitor design. Pharm Res. 1988 Feb;5(2):67–75. [PubMed]
  • Powderly WG. Resistant candidiasis. AIDS Res Hum Retroviruses. 1994 Aug;10(8):925–929. [PubMed]
  • Redding S, Smith J, Farinacci G, Rinaldi M, Fothergill A, Rhine-Chalberg J, Pfaller M. Resistance of Candida albicans to fluconazole during treatment of oropharyngeal candidiasis in a patient with AIDS: documentation by in vitro susceptibility testing and DNA subtype analysis. Clin Infect Dis. 1994 Feb;18(2):240–242. [PubMed]
  • Reents S, Goodwin SD, Singh V. Antifungal prophylaxis in immunocompromised hosts. Ann Pharmacother. 1993 Jan;27(1):53–60. [PubMed]
  • Rex JH, Rinaldi MG, Pfaller MA. Resistance of Candida species to fluconazole. Antimicrob Agents Chemother. 1995 Jan;39(1):1–8. [PMC free article] [PubMed]
  • Sanglard D, Ischer F, Monod M, Bille J. Susceptibilities of Candida albicans multidrug transporter mutants to various antifungal agents and other metabolic inhibitors. Antimicrob Agents Chemother. 1996 Oct;40(10):2300–2305. [PMC free article] [PubMed]
  • Sanglard D, Kuchler K, Ischer F, Pagani JL, Monod M, Bille J. Mechanisms of resistance to azole antifungal agents in Candida albicans isolates from AIDS patients involve specific multidrug transporters. Antimicrob Agents Chemother. 1995 Nov;39(11):2378–2386. [PMC free article] [PubMed]
  • Sarachek A, Henderson LA. Variations for susceptibilities to ultraviolet induced cellular inactivation and gene segregation among protoplast fusion hybrids of Candida albicans. Cytobios. 1988;55(222-223):171–184. [PubMed]
  • Sarachek A, Lovchik JA. Unidirectional internuclear transfer of linked genes in heterokaryons of Candida albicans. J Basic Microbiol. 1989;29(8):527–535. [PubMed]
  • Whelan WL. The genetic basis of resistance to 5-fluorocytosine in Candida species and Cryptococcus neoformans. Crit Rev Microbiol. 1987;15(1):45–56. [PubMed]
  • White TC. Increased mRNA levels of ERG16, CDR, and MDR1 correlate with increases in azole resistance in Candida albicans isolates from a patient infected with human immunodeficiency virus. Antimicrob Agents Chemother. 1997 Jul;41(7):1482–1487. [PMC free article] [PubMed]
  • White TC, Pfaller MA, Rinaldi MG, Smith J, Redding SW. Stable azole drug resistance associated with a substrain of Candida albicans from an HIV-infected patient. Oral Dis. 1997 May;3 (Suppl 1):S102–S109. [PubMed]
  • Yoshida Y, Aoyama Y, Nishino T, Katsuki H, Maitra US, Mohan VP, Sprinson DB. Spectral properties of a novel cytochrome P-450 of a Saccharomyces cerevisiae mutant SG1. A cytochrome P-450 species having a nitrogenous ligand trans to thiolate. Biochem Biophys Res Commun. 1985 Mar 15;127(2):623–628. [PubMed]

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