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Abstract

Understanding the genetic mechanisms involved in resistance to antifungal agents is important in the fight against pathogenic fungi. In the present investigation we studied a strain of the model fungus Aspergillus nidulans which presents resistance to tioconazole and behaves as the wild strain in the presence of other azole derivatives. Genetic analysis revealed that this resistance is due to a mutation in a single gene located on chromosome II, closely linked to the allele responsible for resistance to acriflavine and other acridine derivatives, i.e., acrA1. This result suggests that a multidrug resistance (MDR)-type mechanisms may be involved. Two tioconazole-resistant strains of the pathogenic fungus Trichophyton rubrum obtained after mutagenic treatment also became simultaneously resistant to acriflavine and ethidium bromide, suggesting the existence of a resistance mechanism similar to that observed with the acrA1 mutation in A. nidulans.

Methanol and acriflavine resistance in Dictyostelium are caused by loss of catalase The GenBank accession number for the sequence reported in this paper is AF090443.

“…Genes associated with acriflavine resistance have been identified in different organisms. Molecular cloning of these genes revealed that many of them encode multidrug resistance pumps that transport acri-flavine out of the cell (De Rossi et al, 1998 ;Masaoka et al, 2000 ;Nakaune et al, 1998 ;Pereira et al, 1998). Inactivating mutations in these transporter genes lead to acriflavine sensitivity (Ma et al, 1994).…”