Further in vitro studies with oxiconazole nitrate

Oxiconazole nitrate was compared in vitro with ketoconazole and econazole nitrate in tests with 96 dermatophytes, 18 isolates of Malassezia furfur, and seven isolates of Exophiala werneckii. An agar dilution procedure was used employing either Kimmig's agar or Sabouraud's dextrose agar supplemented with Olive oil and Tween 80. Econazole was the more active compound in tests with Microsporum species (41 isolates) and most isolates of Trichophyton species (45 isolates). Oxiconazole was the more active compound in tests with T. tonsurans and T. rubrum. However, differences between results for oxiconazole and econazole and the dermatophytes were only marginal. Ketoconazole was the most active compound in tests with M. furfur; some cross resistance on the part of several isolates of M. furfur between oxiconazole and econazole was noted. All three compounds were active against E. werneckii with MIC90 values of either 0.25 or 0.5 microgram/ml. Epidermophyton floccosum was the most susceptible of all organisms tested with all MIC values for all three drugs being less than or equal to 0.063 microgram/ml, the lowest concentration tested.