en Anti-microbial agents, resistance and treatment protocols Anti-microbial agents, resistance and treatment protocols Original article Original article <p style="margin: 0px; text-align: justify; line-height: 150%;"><strong>Introduction: </strong>Seborrheic dermatitis is a skin condition that has become widespread in the recent decades. This study aimed to investigate the antimicrobial effect of amniotic fluid of pregnant women on the growth of ketoconazole-resistant <em>Malassezia</em> species isolated from patients with seborrheic dermatitis.<strong> Methods: </strong>We obtained human amniotic fluid from 20 pregnant women during amniocentesis and cesarean delivery at hospitals of Gonbad-e Kavus, northeastern Iran. <em>Malassezia</em> isolates were collected from 120 patients suspected of seborrheic dermatitis and were identified using species-specific&nbsp;biochemical tests. Antibiotic susceptibility and minimum inhibitory concentration (MIC) of <em>Malassezia </em>isolates against ketoconazole were determined by the broth microdilution method. Also, the antifungal effect of various concentrations of amniotic fluid on ketoconazole-resistant <em>Malassezia</em> isolates was assayed using the disk diffusion method. <strong>Results: </strong>&nbsp;The mean MIC of ketoconazole against <em>Malassezia</em> isolates was 0.3 &mu;g/mL, with the most changes observed at 0.5 &mu;g and 1 &mu;g/mL. Ketoconazole &nbsp;inhibited the growth of <em>Malassezia</em> isolates completely, at a concentration of 8 &mu;g/mL. Moreover, amniotic fluid showed inhibitory effects on 60% of ketoconazole-resistant <em>Malassezia furfur </em>isolates and 45% of <em>Malassezia globosa</em> isolates. There was a significant correlation between amniotic fluid concentration and the diameter of the growth inhibition zone (<em>P</em><0.01). <strong>Conclusion:</strong> Our findings indicated that amniotic fluid could exhibit favorable dose-dependent antifungal activity against ketoconazole-resistant <em>Malassezia</em> isolates from patients with seborrheic dermatitis. Further studies are required to confirm the efficiency of amniotic fluid for the treatment of such infections.</p> Dermatitis, Seborrheic, Amniotic Fluid, Antifungal Agent 19 23 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-196-2&slc_lang=en&sid=1 Mohadeseh Nasiri ir.nasiri1@gmail.com 0000-0003-3077-1888 No Department of Biology, Gorgan Branch, Islamic Azad University, Gorgan, Iran Leila Fozouni lili_kia@yahoo.com 0000000222480354 Yes Department of Biology, Gorgan Branch, Islamic Azad University, Gorgan, Iran