Antifungal activity of miconazole against recent Candida strains

Abstract

Miconazole (MICON) has long been used for the topical treatment of mucosal candidiasis. However, the preponderance of MICON susceptibility data was generated before standard methodology was established, and prior to the emergence of fluconazole (FLU)-resistant strains. The objective of this study was to determine the antifungal activity of MICON and comparators against recent clinical isolates of Candida spp. using standard Clinical and Laboratory Standards Institute methodology. One hundred and fifty isolates, consisting of 25 strains each of Candida albicans, C. krusei, C. glabrata, C. tropicalis, C. parapsilosis and C. dubliniensis, were tested. Of these, twenty-two strains were known to be FLU-resistant. Minimum inhibitory concentrations (MICs) were determined for MICON, amphotericin B (AM), caspofungin (CAS), clotrimazole (CLOT), FLU, itraconazole (ITRA), nystatin (NYS) and voriconazole (VOR). MICON demonstrated potent inhibitory activity against all of the strains tested. The MIC(90) for MICON was 0.12 microg ml(-1) against FLU-susceptible strains, which was comparable to that of AM, CAS, CLOT, ITRA and VOR. The MICON MIC(90) against FLU-resistant strains was 0.5 microg ml(-1), which was 12-fold lower than the FLU MIC(90). Our study showed that MICON possesses potent activity against all of the Candida isolates tested, including those with known FLU resistance. This indicates that recent clinical isolates remain susceptible to this antifungal and that MICON could be used as first-line treatment for oropharyngeal candidiasis.