In vitro sensitivity of environmental isolates of pathogenic dematiaceous fungi to azole compounds and a phenylpropyl-morpholine derivative.

Abstract

The in vitro sensitivity (minimum inhibitory concentrations; MICs) of 42 environmental isolates of pathogenic dematiaceous fungi to 7 azole compounds, viz. thiabendazole, ketoconazole, miconazole, econazole bifonazole, Bay n 7133, Bay 1 9139 and phenylpropyl-morpholine derivative, Ro14-4767/002 was studied by an agar dilution method using Emmon's Sabouraud dextrose agar (ESDA) as the culture medium. The isolates of Fonsecaea pedrosoi, Cladosporium carrionii, Exophiala jeanselmei and Ramichloridium subulatum were most sensitive to bifonazole with mean MICs of 0.06 microgram/ml or less; Phialophora verrucosa had an MIC of 0.05 microgram/ml to ketoconazole and Ro14-4767/002, respectively. Ochroconis sp had an MIC of 0.025 microgram/ml to Ro14-4767/002 and Cladosporium tennuisimum 0.39 microgram/ml to ketoconazole. Econazole and thiabendazole also showed good antifungal activity. The fungi were relatively resistant to the more recently developed azoles, viz. Bay n 7133 and Bay 1 9139, the later failing to inhibit C. tennuisimum at a concentration of 100 micrograms/ml. The minimum fungicidal concentrations (MFC) of the drugs were mostly within 2 to 8 fold of the MICs.