BackgroundThe Malassezia yeasts which belong to the physiological microflora of human skin have also been implicated in several dermatological disorders, including pityriasis versicolor (PV), atopic dermatitis (AD), and psoriasis (PS). The Malassezia genus has repeatedly been revised and it now accommodates 14 species, all but one being lipid-dependent species. The traditional, phenotype-based identification schemes of Malassezia species are fraught with interpretative ambiguities and inconsistencies, and are thus increasingly being supplemented or replaced by DNA typing methods. The aim of this study was to explore the species composition of Malassezia microflora on the skin of healthy volunteers and patients with AD and PS.MethodsSpecies characterization was performed by conventional, culture-based methods and subsequently molecular techniques: PCR-RFLP and sequencing of the internal transcribed spacer (ITS) 1/2 regions and the D1/D2 domains of the 26S rRNA gene. The Chi-square test and Fisher’s exact test were used for statistical analysis.ResultsMalassezia sympodialis was the predominant species, having been cultured from 29 (82.9%) skin samples collected from 17 out of 18 subjects under the study. Whereas AD patients yielded exclusively M. sympodialis isolates, M. furfur isolates were observed only in PS patients. The isolation of M. sympodialis was statistically more frequent among AD patients and healthy volunteers than among PS patients (P < 0.03). Whether this mirrors any predilection of particular Malassezia species for certain clinical conditions needs to be further evaluated. The overall concordance between phenotypic and molecular methods was quite high (65%), with the discordant results being rather due to the presence of multiple species in a single culture (co-colonization) than true misidentification. All Malassezia isolates were susceptible to cyclopiroxolamine and azole drugs, with M. furfur isolates being somewhat more drug tolerant than other Malassezia species.ConclusionsThis study provides an important insight into the species composition of Malassezia microbiota in human skin. The predominance of M. sympodialis in both normal and pathologic skin, contrasts with other European countries, reporting M. globosa and M. restricta as the most frequently isolated Malassezia species.

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T. rubrum strains are more susceptible to antifungal drugs than T. mentagrophytes. Naftifine proved to be the most effective drug in dermatophytoses. Natamycin is a useful drug against yeast-like fungi but not against dermatophytes. The disk-diffusion method of fungal susceptibility assessment yields data consistent with results obtained from the dilution method and is recommended for routine use because of its simplicity.

In humans, Scopulariopsis is mainly associated with onychomycoses, rarely with cutaneous infections or with invasive mycoses. However, during the last two decades, deep infections caused by members of this genus have been increasing. Scopulariopsis brevicaulis is the most common species described as an etiologic agent of human disease. Previous antifungal susceptibility studies indicate that this species is resistant in vitro to the broad-spectrum antifungal agents that are available today. Here, we describe the antifungal activity of amphotericin B, terbinafine, ciclopirox, itraconazole, ketoconazole, and voriconazole against 40 S. brevicaulis isolates. Antifungal susceptibility tests were performed using a modified Clinical and Laboratory Standards Institute M38-A2 procedure. The results showed that itraconazole had the highest minimal inhibitory concentration (MIC) of >16 mg/l; amphotericin B, voriconazole, and ketoconazole MICs were ranging from 4 to >16 mg/l, 8 to >16 mg/l, and 8 to >16 mg/l, respectively; and the best activity was found with terbinafine and ciclopirox with MICs ranging from 0.5 to 16 mg/l and 1 to 8 mg/l, respectively.

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