IDENTIFICATION OF HEMOLYTIC-ACTIVITY IN PREVOTELLA-INTERMEDIA

Hemolysin production was measured in strains of Prevotella intermedia. Zones of beta-hemolysis were detected on agar plates supplemented wit h either sheep, rabbit or human erythrocytes. A standard tube assay wa s performed on cell suspensions of the organism to measure hemolytic a ctivity, which was found to be dose dependent, eliminated by heat trea tment, and saturable with increasing concentrations of blood. Growth-p hase experiments suggested that hemolysin production was increased dur ing logarithmic growth and was reduced during stationary phase. Cell f ractionation, performed on several strains of P. intermedia, localized the activity in the outer membrane and in cell vesicles. The biologic al implication of this study is that P. intermedia, by virtue of its h emolytic activity, is capable of liberating the hemoglobin from erythr ocytes, thereby acquiring an essential nutrient, iron, for its metabol ism.