Presence of Hemolysin in Cultures of Pathogenic Leptospires

Abstract

The presence of a non-dialysable, thermolabile O2-stable hemolysin was demonstrated in the supernatant fluid of a culture of pathogenic leptospires isolated from a human patient in Malaya. Previous serologic studies disclosed this strain to be a new heterologous serotype member of the hebdomadis serogroup; consequently, this serotype was designated as Leptospira hemolyticus. Studies conducted with this strain disclosed that the optimal temperature for hemolytic activity against sheep erythrocytes (RBC) was 37[degree]C. At lower temperatures the activity progressively decreased. Hemolytic activity against sheep RBC occurred after a prolonged induction period. This phenomen, as well as the atypical kinetic activity of varying concentrations of hemolysin, was attributed to the inhibitory activity of rabbit serum present in the culture milieu. A screening of 36 serotype strains for hemolytic activity showed that this characteristic was not a generic property, but was restricted to specific serotype strains. Hemolytic activity of L. hemolyticus culture supernatant fluid was manifested against sheep, cow, goat RBC but not against RBC from 11 other spp. screened. The antigenicity of the hemolysin could not be demonstrated.