The strict nutritional requirements of Malassezia species make it difficult to test the antifungal susceptibility. Treatments of the chronic and recurrent infections associated with Malassezia spp. are usually ineffective. The objective of this study was to obtain in vitro susceptibility profile of 76 clinical isolates of Malassezia species against 16 antifungal drugs used for topical or systemic treatment. Isolates were identified by restriction fragment length polymorphism. Minimal inhibitory concentrations (MIC) were obtained by a modified microdilution method based on the Clinical Laboratory Standards Institute reference document M27-A3. The modifications allowed a good growth of all tested species. High in vitro antifungal activity of most tested drugs was observed, especially triazole derivatives, except for fluconazole which presented the highest MICs and widest range of concentrations. Ketoconazole and itraconazole demonstrated a great activity. Higher MICs values were obtained with Malassezia furfur indicating a low susceptibility to most of the antifungal agents tested. Malassezia sympodialis and Malassezia pachydermatis were found to be more-susceptible species than M. furfur, Malassezia globosa, Malassezia slooffiae and Malassezia restricta. Topical substances were also active but provide higher MICs than the compounds for systemic use. The differences observed in the antifungals activity and interspecies variability demonstrated the importance to studying the susceptibility profile of each species to obtain reliable information for defining an effective treatment regimen.

The in vitro activity of sertaconazole was compared with that of terbinafine and bifonazole against 180 Candida spp., Cryptococcus neoformans yeasts and 53 dermatophytes. Minimum inhibitory concentrations (MICs) were determined by a microdilution method in Sabouraud’s buffered liquid medium (pH 5.6). Sertaconazole (arithmetic mean MIC 1.24 mg/l) was statistically more active than bifonazole (MIC 6.54 mg/l) and terbinafine (MIC 12.61 mg/l) against yeasts strains, MIC values for sertaconazole being generally and specifically lower for each tested yeast species. MIC for C. parapsilosis (0.26 mg/l) demonstrated a higher activity of sertaconazole against this species, in contrast to C tropicalis (MIC 1.49 mg/l). Against dermatophytes, MIC for terbinafine (0.05 mg/l) was lower than sertaconazole (MIC 0.41 mg/l) and bifonazole (MIC 1.04 mg/l). These results, obtained under the same experimental conditions, confirm the good antifungal activity of sertaconazole against both yeasts and dermatophytes with lower MICs obtained in the topical application. This in vitro activity correlates with the clinical efficacy of sertaconazole compared with other antifungal agents.

Sertaconazole is a useful antifungal agent against mycoses of the skin and mucosa, such as cutaneous, genital and oral candidiasis and tinea pedis. Its antifungal activity is due to inhibition of the ergosterol biosynthesis and disruption of the cell wall. At higher concentrations, sertaconazole is able to bind to nonsterol lipids of the fungal cell wall, increasing the permeability and the subsequent death of fungal cells. Fungistatic and fungicidal activities on Candida are dose-dependent. The antifungal spectrum of sertaconazole includes deramophytes, Candida, Cryptococcus, Malassezia and also Aspergillus, Scedosporium and Scopulariopsis. Sertaconazole also shows an antimicrobial activity against streptococci, staphylococci and protozoa (Trichomonas). In clinical trials including patients with vulvovaginal candidiasis, a single dose of sertaconazole produced a higher cure rate compared with other topical azoles such as econazole and clotrimazole, in shorter periods. Sertaconazole has shown an anti-inflammatory effect that is very useful for the relief of unpleasant symptoms.

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