Killer phenomenon in pathogenic yeast.

Potentially pathogenic yeast strains from four genera, Candida, Cryptococcus, Torulopsis, and Trichosporon, were examined for killer activity and sensitivity using Saccharomyces and Torulopsis strains of known killer status. Tests were performed by using a streak method and by concentration of culture fluid by lyophilization. Of 236 strains examined, killers were found with low prevalence among Torulopsis and Cryptococcus strains; Candida and Trichosporon isolates showed no killing activity. Different specificities of killing activity were observed among strains of a single species. Sensitive strains were found with varying frequencies in all genera but Trichosporon.