Format

Send to

Choose Destination
See comment in PubMed Commons below
J Antimicrob Chemother. 2001 Jul;48(1):75-81.

Resistance to itraconazole in Aspergillus nidulans and Aspergillus fumigatus is conferred by extra copies of the A. nidulans P-450 14alpha-demethylase gene, pdmA.

Author information

1
Division of Pathology and Laboratory Medicine, and Department of Internal Medicine Specialties, Section of Infectious Diseases, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.

Abstract

Triazoles selectively inhibit the cytochrome P-450-dependent C-14 lanosterol alpha-demethylase (P-450 14 alpha DM), a key enzyme in ergosterol biosynthesis in fungi. To investigate mechanisms of triazole resistance in a mould, we used Aspergillus nidulans, a genetically amenable model fungus closely related to more pathogenic members of the genus. We selected for genes that would give resistance to itraconazole following transformation with a high copy genomic library of A. nidulans. In all the resistant colonies that we isolated, resistance was conferred by extra copies of the A. nidulans P-450 14 alpha DM gene, pdmA. We determined that in A. nidulans, extra copies of pdmA increase the MIC for itraconazole 36 times over wild-type controls. Similarly, transformation of an Aspergillus fumigatus strain with pITZR1 resulted in increased resistance to itraconazole. Our results indicate that triazole resistance in clinical isolates of moulds may result from amplification or overexpression of the P-450 14 alpha DM and demonstrate the utility of A. nidulans as a promising model fungus for the analysis of drug resistance and susceptibility in the pathogenic fungus A. fumigatus.

PMID:
11418514
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Loading ...
    Support Center