IN-VITRO SUSCEPTIBILITY OF TRICHOPHYTON-RUBRUM ISOLATES TO GRISEOFULVIN AND TIOCONAZOLE - INDUCTION AND ISOLATION OF A RESISTANT MUTANT TO BOTH ANTIMYCOTIC DRUGS - MUTANT OF TRICHOPHYTON-RUBRUM RESISTANT TO GRISEOFULVIN AND TIOCONAZOLE

The in vitro susceptibility of three clinical Trichophyton rubrum isol ates to griseofulvin and tioconazole, determined by the minimal inhibi tory concentration(MIC), was 2 and 0.5 to 1.0 mu g/ml, respectively. O ne mutant (grill obtained after mutagenic treatment of one of these is olates was selected and showed simultaneous resistance to griseofulvin (MIC > 2000 mu g/ml) and tioconazole (MIC = 1.0 mu g/ml). The clinica l importance and the possibility of a multidrug resistance (MDR)-type mechanism being involved in this event is discussed.