A new naphthaquinone antibiotic from a new species of yeast.

A fusiform yeast producing limited pseudomycelium and limited true mycelium on malt extract agar has been isolated. This non-fermentative yeast has hyaline cell walls but produces a thick, black oily exudate which is water insoluble and gives the colony a smooth black lacquered appearance. On the basis of morphology and physiology, this organism is distinctive enough to warrant the designation of a new genus. During stationary phase of cultures on chemically defined medium, a deep red substance is produced which has strong antibiotic activity against Staphylococcus aureus in vitro. The substance has been identified as a new natural naphthaquinone of the empirical formula C16H16O7 .