The gene that determines resistance to tioconazole and to acridine derivatives in Aspergillus nidulans may have a corresponding gene in Trichophyton rubrum

Understanding the genetic mechanisms involved in resistance to antifungal a gents is important in the fight against pathogenic fungi. In the present in vestigation we studied a strain of the model fungus Aspergillus nidulans wh ich presents resistance to tioconazole and behaves as the wild strain in th e 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 multid rug resistance (MDR)-type mechanism may be involved. Two tioconazole-resist ant strains of the pathogenic fungus Trichophyton rubrum obtained after mut agenic treatment also became simultaneously resistant to acriflavine and et hidium bromide, suggesting the existence of a resistance mechanism similar to that observed with the act-Al mutation in A. nidulans.