agar and Tinea-Versicolor

Lipophilic basidiomycetous yeasts of the Malassezia genus can cause various skin diseases, such as seborrheic dermatitis, pityriasis versicolor, folliculitis and atopic dermatitis, and even life-threatening fungemia in newborns and immunocompromised individuals. Routine mycological media used in clinical practice do not contain sufficient lipid ingredients required for the growth of Malassezia species. A recently developed medium, FastFung agar, is promising for culturing fastidious fungal species.. In this study, we compared FastFung agar and mDixon agar for culturing Malassezia species from nasolabial fold and retroauricular specimens of 83 healthy individuals and 187 and 57 patients with acne vulgaris and seborrheic dermatitis, respectively.. Malassezia species were identified using conventional tests and matrix-assisted laser desorption/ionisation mass spectrometry. In total, 96 of 654 samples (14.6%) contained Malassezia species. The total isolation rate was significantly higher in patients with seborrheic dermatitis (40.4%) than in healthy volunteers (21.7%; p < .05), and the rate of M. furfur isolation was significantly higher for patients with acne vulgaris (13.9%) and seborrheic dermatitis (24.6%) than for healthy individuals (1.5%; p < .05). FastFung agar was superior to mDixon agar in M. furfur isolation (p = .004) but showed similar performance in the case of non-M. furfur species (p > .05). Among cultured Malassezia species, perfect agreement between mDixon agar and FastFung agar was found only for M. globosa (κ = 0.90).. Our results indicate that FastFung agar favours the growth of Malassezia species and should be useful in clinical mycology laboratories.

Topics: Acne Vulgaris; Agar; Dermatitis, Seborrheic; Humans; Infant, Newborn; Malassezia; Skin; Tinea Versicolor

The genus Malassezia represents the dominant eukaryotic component of the skin microbial flora. There are complex interactions between this commensal and the skin, leading to various Malassezia-caused or Malassezia exacerbated skin conditions.. To identify Malassezia species in lesions of patients with pityriasis versicolor (PV), atopic dermatitis (AD), and seborrheic dermatitis (SD), as well as corresponding sites in healthy subjects according to the culture methods used for Malassezia species isolation.. Scrapings were collected from 80 patients (40 PV, 20 AD, and 20 SD) and 30 healthy subjects. For 10-14 days, specimens were cultured on Dixon's medium and Malt extract agar. Direct microscopic examination with Gram's stain, subculture on Hi chrome agar, Dixon's medium at various temperatures, Tweens assimilation, and hydrolysis of tryptophan were used for the identification of yeast isolates.. The isolation frequency of Malassezia species in healthy subjects was 13.3% for M. furfur, 10.0% for M. globosa, and 3.3% for M.sympodialis. In patients with SD, M. furfur was isolated more frequently from scalp lesions (25.0%) and then M. sympodialis (15%) and M. globosa (10%). Malassezia sympodialis was the most prevalent isolated species in AD lesions (20%), followed by M. furfur (10%). Malassezia species isolation was found to be most prevalent in PV lesions, with M. furfur being the most prevalent identified species (52.5 %), followed by unidentified species (20%).. Malassezia species composition was similar in PV, SD, and healthy subjects, with M. furfur being the commonest isolate, while Malassezia sympodialis was the prevalent species isolated in AD lesions. Chrome agar media can be promising for the identification of Malassezia species phenotypically. However, species differentiation has to be complemented by molecular methods.

Topics: Agar; Dermatitis, Atopic; Humans; Malassezia; Skin; Tinea Versicolor