Rice bran oil supports robust growth of the commensal fungus Malassezia

Abstract

Malassezia are lipophilic budding yeasts that thrive on natural lipid sources. They are found on the skin, scalp, and upper back of humans and other warm-blooded animals, due to the high sebaceous gland activity in these regions that support their growth. They generally thrive as commensals and, upon certain not-so-well-defined conditions, transform into pathogenic states, giving rise to dermatological diseases and, at times, systemic infections. The studies for identifying the role of Malassezia in causing disease are severely hampered due to the lack of suitable growth media. Because of the challenges associated with isolation, there have been cases reported of undetectable fungal sepsis and often misdiagnosis for the same reason. The media routinely used for culturing yeast is supplemented with lipids. This study aimed to show that an inexpensive oil supplement like rice bran can support the growth of Malassezia, and SDA media supplemented with rice bran oil gave commendable growth of the budding yeast, better than the traditionally used olive oil-supplemented media. Therefore, rice bran oil can be used as a lipid supplement in the culture medium for the isolation, and maintenance of lipophilic yeasts. Our study again signifies the importance of media in microbiological research and stresses the need to develop better growth substrates for difficult-to-culture organisms like Malassezia and this will aid in molecular taxonomy, species characterization and phylogenetic studies.