M-DIXON AGAR, 500G/BTL

m-Dixon Agar is a medium used for the culture and isolation of the Malassezia species. The species of the genus Malassezia are found in the microbial flora that inhabit the skin of homeothermic animals. Most of the species of this genus are lipid-dependent yeasts that colonize the seborrheic part of the skin and they are described as being associated with Tinea versicolor or seborrheic dermatitis. Some Malassezia species can produce precipitates in the medium. It is likely that the appearance of precipitates is due to the production of free fatty insoluble acids from lipid sources contained in Dixon Agar. Moreover, it is possible that, to the degree the isolation continues to grow, some of these fatty acid precipitates are used, which would explain the appearance of clear visible areas directly adjacent to the microbial growth. It is known that species of Malassezia have differences in their patterns of lipid use, and it has also been proven that M. sympodalis produces comparatively more free fatty insoluble acids from lipid sources than M. furfur. These observations suggest differences in the systems of lipase enzymes in species of Malassezia. Casein peptone provides nitrogen, vitamins, minerals and amino acids essential for growth. The malt extract is a source of carbon, proteins and nutrients, also necessary for growth. This medium is adequate for yeasts and molds as it contains a high concentration of maltose and other saccharides as sources of energy. The adding of ox bile inhibits the growth of Gram-positive organisms. The oleic acid and tween 40 are a source of lipids. The cycloheximide is an antibiotic which inhibits saprophytic fungi, but allows the growth of pathogenic fungi.