Anti-Microbial Effect of Aloe vera Extract on Clotrimazole-Resistant Malassezia Furfur Strains Isolated From Patients with Seborrheic Dermatitis in the City of Sari

Malassezia is a dimorphic and lipophilic fungus that causes skin diseases in opportunistic conditions. The aim of the present study was to investigate the antimicrobial activity of Aloe vera extract on growth of clotrimazole-resistant Malassezia furfur isolated from patients with seborrheic dermatitis. In this descriptive cross-sectional study, 102 samples were selected from skin lesions of suspected cases of seborrheic dermatitis. Malassezia isolates were identified by biochemical tests. To determine drug sensitivity, the broth microdilution method was used. After preparation of Aloe vera extract, the antifungal effect of different concentrations of this extract on clotrimazole-resistant isolates was determined by uing the agar well diffusion method, and its minimum inhibitory concentration (MIC) was evaluated by the broth microdilution method. In this study, 72 strains of Malassezia were isolated, out of which the highest frequency belonged to Malassezia furfur with a frequency of 56 (77.8%) cases, while 50% of them were resistant to clotrimazole. Upon evaluation of antifungal effects of Aloe vera extract, the maximum inhibition zone diameter was seen for the extract in the concentration of 250 mg/mL. This parameter was observed for yeast isolates resistant to clotrimazole at the mean of 25 mm. Changes to the MIC of Aloe vera extract in the range of 1024 - 2 μL/mL showed that 89% of Malassezia furfur isolates resistant to clotrimazole did not grow in concentrations with MIC ≥ 512 μL/mL (P < 0.001). According to our results, Aloe vera extract showed proper inhibitory effects against clinical clotrimazole-resistant Malassezia furfur isolates at high concentrations. Therefore, we could hope to treat fungal diseases by producing an appropriate herbal medicine.