Sterol composition in polyene antibiotic-sensitive and resistant strains of Malassezia pachydermatis.

The membrane sterol compositions of ten strains of Malassezia pachydermatis were analysed by gas-liquid chromatography. Six of these were wild-type strains from clinical sources that were sensitive to polyene antibiotics, whereas the other four strains were resistant mutants that had arisen after treatment with N-methyl-N'-nitrosoguanidine or UV radiation. The wild-type strains contained 838.8 to 1291.7 micrograms of sterol per gram of freeze-dried mycelium. The sterols were composed of 79% ergosterol, 19% fecosterol and 2% lichesterol. The mutant strains contained 277.1 to 348.8 micrograms/g of sterols composed of 76% ergosterol and 24% fecosterol.