Production of indirect hemolysin by Yersinia enterocolitica and its properties

Hemolysis was demonstrated on blood agar by adding lecithin from strains of biovar 1 Yersinia enterocolitica. Hemolytic activity was also observed in culture filtrates containing lecithin. No hemolytic activity was detected from any blood agar or culture filtrate without lecithin or after incubation at 37 degrees C. Crude indirect hemolysin was prepared by ammonium sulfate fractionation from culture filtrates, and two enzymes, phospholipase A and lipase, were fractionated by gel filtration. Hemolytic substances were recognized as lysolecithin and fatty acid when lecithin wad decomposed by phospholipase A and lipase, respectively.