Effect of sub-MICs of antimycotics on expression of intracellular esterase of Trichophyton rubrum.

The electrophoretic pattern of the intracellular esterase of the dermatophyte Trichophyton rubrum was altered when this fungus was grown in the presence of subinhibitory concentrations of the antimycotics tioconazole or griseofulvin. All strains (original isolate and antimycotic resistant mutants) presented five clearly visible bands when cultivated on medium containing below-minimum inhibitory concentrations (sub-MICs) of tioconazole or griseofulvin, and only two clearly visible bands when cultivated in medium without antimycotics. No extra bands were detected in the electrophoretic patterns of the extracellular esterase of these fungi (mutants or the original isolate) when cultivated with or without tioconazole or griseofulvin (sub-MIC values). These results suggest that additional forms of esterase are produced inside the cell and may be a nonspecific response to cellular stress, or may participate in cellular detoxification processes in the presence of these antimycotics.