Skip to main content
PMC home page
Antimicrobial Agents and Chemotherapy logoLink to Antimicrobial Agents and Chemotherapy
. 1997 Jun;41(6):1364–1368. doi: 10.1128/aac.41.6.1364

Itraconazole resistance in Aspergillus fumigatus.

D W Denning 1, K Venkateswarlu 1, K L Oakley 1, M J Anderson 1, N J Manning 1, D A Stevens 1, D W Warnock 1, S L Kelly 1
PMCID: PMC163916  PMID: 9174200

Abstract

Invasive aspergillosis is an increasingly frequent opportunistic infection in immunocompromised patients. Only two agents, amphotericin B and itraconazole, are licensed for therapy. Itraconazole acts through inhibition of a P-450 enzyme undertaking sterol 14alpha demethylation. In vitro resistance in Aspergillus fumigatus to itraconazole correlated with in vivo outcome has not been previously described. For three isolates (AF72, AF90, and AF91) of A. fumigatus from two patients with invasive aspergillosis itraconazole MICs were elevated. A neutropenic murine model was used to establish the validity of the MICs. The isolates were typed by random amplification of polymorphic DNA. Analysis of sterols, inhibition of cell-free sterol biosynthesis from [14C] mevalonate, quantitation of P-450 content, and [3H]itraconazole concentration in mycelial pellets were used to determine the mechanisms of resistance. The MICs for the three resistant isolates were >16 microg/ml. In vitro resistance was confirmed in vivo for all three isolates. Molecular typing showed the isolates from the two patients to be genetically distinct. Compared to the susceptible isolate from patient 1, AF72 had a reduced ergosterol content, greater quantities of sterol intermediates, a similar susceptibility to itraconazole in cell-free ergosterol biosynthesis, and a reduced intracellular [3H]itraconazole concentration. In contrast, AF91 and AF92 had slightly higher ergosterol and lower intermediate sterol concentrations, fivefold increased resistance in cell-free systems to the effect of itraconazole on sterol 14alpha demethylation, and intracellular [3H] itraconazole concentrations found in susceptible isolates. Resistance to itraconazole in A. fumigatus is detectable in vitro and is present in wild-type isolates, and at least two mechanisms of resistance are responsible.

Full Text

The Full Text of this article is available as a PDF (399.3 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Anderson M. J., Gull K., Denning D. W. Molecular typing by random amplification of polymorphic DNA and M13 southern hybridization of related paired isolates of Aspergillus fumigatus. J Clin Microbiol. 1996 Jan;34(1):87–93. doi: 10.1128/jcm.34.1.87-93.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Ballard S. A., Ellis S. W., Kelly S. L., Troke P. F. A novel method for studying ergosterol biosynthesis by a cell-free preparation of Aspergillus fumigatus and its inhibition by azole antifungal agents. J Med Vet Mycol. 1990;28(4):335–344. [PubMed] [Google Scholar]
  3. Ben-Yaacov R., Knoller S., Caldwell G. A., Becker J. M., Koltin Y. Candida albicans gene encoding resistance to benomyl and methotrexate is a multidrug resistance gene. Antimicrob Agents Chemother. 1994 Apr;38(4):648–652. doi: 10.1128/aac.38.4.648. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Bodey G., Bueltmann B., Duguid W., Gibbs D., Hanak H., Hotchi M., Mall G., Martino P., Meunier F., Milliken S. Fungal infections in cancer patients: an international autopsy survey. Eur J Clin Microbiol Infect Dis. 1992 Feb;11(2):99–109. doi: 10.1007/BF01967060. [DOI] [PubMed] [Google Scholar]
  5. Carlson G. L., Mughal M. M., Birch M., Denning D. W. Aspergillus wound infection following laparostomy. J Infect. 1996 Sep;33(2):119–121. doi: 10.1016/s0163-4453(96)93062-5. [DOI] [PubMed] [Google Scholar]
  6. Denning D. W., Clemons K. V., Hanson L. H., Stevens D. A. Restriction endonuclease analysis of total cellular DNA of Aspergillus fumigatus isolates of geographically and epidemiologically diverse origin. J Infect Dis. 1990 Nov;162(5):1151–1158. doi: 10.1093/infdis/162.5.1151. [DOI] [PubMed] [Google Scholar]
  7. Denning D. W., Follansbee S. E., Scolaro M., Norris S., Edelstein H., Stevens D. A. Pulmonary aspergillosis in the acquired immunodeficiency syndrome. N Engl J Med. 1991 Mar 7;324(10):654–662. doi: 10.1056/NEJM199103073241003. [DOI] [PubMed] [Google Scholar]
  8. Denning D. W., Hall L., Jackson M., Hollis S. Efficacy of D0870 compared with those of itraconazole and amphotericin B in two murine models of invasive aspergillosis. Antimicrob Agents Chemother. 1995 Aug;39(8):1809–1814. doi: 10.1128/aac.39.8.1809. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Denning D. W., Hanson L. H., Perlman A. M., Stevens D. A. In vitro susceptibility and synergy studies of Aspergillus species to conventional and new agents. Diagn Microbiol Infect Dis. 1992 Jan;15(1):21–34. doi: 10.1016/0732-8893(92)90053-v. [DOI] [PubMed] [Google Scholar]
  10. Denning D. W., Hanson L. H., Stevens D. A. In vitro activity of saperconazole (R66 905) compared with amphotericin B and itraconazole against Aspergillus species. Eur J Clin Microbiol Infect Dis. 1990 Sep;9(9):693–697. doi: 10.1007/BF01964275. [DOI] [PubMed] [Google Scholar]
  11. Denning D. W., Tucker R. M., Hanson L. H., Stevens D. A. Treatment of invasive aspergillosis with itraconazole. Am J Med. 1989 Jun;86(6 Pt 2):791–800. doi: 10.1016/0002-9343(89)90475-0. [DOI] [PubMed] [Google Scholar]
  12. Hitchcock C. A., Pye G. W., Troke P. F., Johnson E. M., Warnock D. W. Fluconazole resistance in Candida glabrata. Antimicrob Agents Chemother. 1993 Sep;37(9):1962–1965. doi: 10.1128/aac.37.9.1962. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Hostetler J. S., Hanson L. H., Stevens D. A. Effect of cyclodextrin on the pharmacology of antifungal oral azoles. Antimicrob Agents Chemother. 1992 Feb;36(2):477–480. doi: 10.1128/aac.36.2.477. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Joseph-Horne T., Hollomon D., Loeffler R. S., Kelly S. L. Altered P450 activity associated with direct selection for fungal azole resistance. FEBS Lett. 1995 Oct 30;374(2):174–178. doi: 10.1016/0014-5793(95)01102-k. [DOI] [PubMed] [Google Scholar]
  15. Joseph-Horne T., Manning N. J., Hollomon D., Kelly S. L. Defective sterol delta 5(6) desaturase as a cause of azole resistance in Ustilago maydis. FEMS Microbiol Lett. 1995 Mar 15;127(1-2):29–34. doi: 10.1111/j.1574-6968.1995.tb07445.x. [DOI] [PubMed] [Google Scholar]
  16. Kelly S. L., Lamb D. C., Kelly D. E., Loeffler J., Einsele H. Resistance to fluconazole and amphotericin in Candida albicans from AIDS patients. Lancet. 1996 Nov 30;348(9040):1523–1524. doi: 10.1016/S0140-6736(05)65949-1. [DOI] [PubMed] [Google Scholar]
  17. Masaphy S., Levanon D., Henis Y., Venkateswarlu K., Kelly S. L. Evidence for cytochrome P-450 and P-450-mediated benzo(a)pyrene hydroxylation in the white rot fungus Phanerochaete chrysosporium. FEMS Microbiol Lett. 1996 Jan 1;135(1):51–55. doi: 10.1111/j.1574-6968.1996.tb07965.x. [DOI] [PubMed] [Google Scholar]
  18. Moore C. B., Law D., Denning D. W. In-vitro activity of the new triazole D0870 compared with amphotericin B and itraconazole against Aspergillus spp. J Antimicrob Chemother. 1993 Dec;32(6):831–836. doi: 10.1093/jac/32.6.831. [DOI] [PubMed] [Google Scholar]
  19. OMURA T., SATO R. THE CARBON MONOXIDE-BINDING PIGMENT OF LIVER MICROSOMES. I. EVIDENCE FOR ITS HEMOPROTEIN NATURE. J Biol Chem. 1964 Jul;239:2370–2378. [PubMed] [Google Scholar]
  20. Parkinson T., Falconer D. J., Hitchcock C. A. Fluconazole resistance due to energy-dependent drug efflux in Candida glabrata. Antimicrob Agents Chemother. 1995 Aug;39(8):1696–1699. doi: 10.1128/aac.39.8.1696. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Prasad R., De Wergifosse P., Goffeau A., Balzi E. Molecular cloning and characterization of a novel gene of Candida albicans, CDR1, conferring multiple resistance to drugs and antifungals. Curr Genet. 1995 Mar;27(4):320–329. doi: 10.1007/BF00352101. [DOI] [PubMed] [Google Scholar]
  22. Rinaldi M. G. Invasive aspergillosis. Rev Infect Dis. 1983 Nov-Dec;5(6):1061–1077. doi: 10.1093/clinids/5.6.1061. [DOI] [PubMed] [Google Scholar]
  23. Sanglard D., Kuchler K., Ischer F., Pagani J. L., 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. doi: 10.1128/aac.39.11.2378. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Vanden Bossche H., Marichal P., Odds F. C. Molecular mechanisms of drug resistance in fungi. Trends Microbiol. 1994 Oct;2(10):393–400. doi: 10.1016/0966-842x(94)90618-1. [DOI] [PubMed] [Google Scholar]
  25. Venkateswarlu K., Denning D. W., Manning N. J., Kelly S. L. Resistance to fluconazole in Candida albicans from AIDS patients correlated with reduced intracellular accumulation of drug. FEMS Microbiol Lett. 1995 Sep 15;131(3):337–341. doi: 10.1111/j.1574-6968.1995.tb07797.x. [DOI] [PubMed] [Google Scholar]
  26. vanden Bossche H., Marichal P., Odds F. C., Le Jeune L., Coene M. C. Characterization of an azole-resistant Candida glabrata isolate. Antimicrob Agents Chemother. 1992 Dec;36(12):2602–2610. doi: 10.1128/aac.36.12.2602. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Antimicrobial Agents and Chemotherapy are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES