In vitro studies with miconazole and miconazole nitrate.

The in vitro activity of miconazole and miconazole nitrate against a variety of pathogenic and saprophytic fungi was studied using an agar dilution procedure. 28 dimorphic pathogens were tested: Histoplasma capsulatum and Blastomyces dermatitidis were the most susceptible with inhibition of all strains at 0.5 ug/ml of either compound. Coccidioides immitis was somewhat more resistant requiring 1 or 2 ug/ml for inhibition, while 4 isolates of Sporothrix schenckii required 2 to 4 ug/ml for complete inhibition. All strains of Cryptococcus neuformans were susceptible to 1 ug/ml or less. Most strains of Candida albicans were resistant to less than 16 ug/ml; other species of Candida were inhibited by 4 ug/ml or less. Torulopsis isolates gave a range of MIC’s from 0.5 ug/ml to 16 ug/ml for inhibition. Of 15 dematiaceous isolates tested, all but two were inhibited at 4 ug/ml or less. A brief discussion of the possible clinical usefulness of miconazole is given.