title: Rickettsial hemolysis: rapid method for enumeration of metabolically active typhus rickettsiae.
abstract: A new assay is described for enumerating biologically active typhus rickettsiae (Madrid E strain), based on adsorption of rickettsiae to erythrocytes in the presence of NaF (which allows adsorption but not lysis) and lysis in the presence of anti-Rickettsia prowazeki immune serum (which allows only a single round of lysis). The number of lysed erythrocytes is then used to estimate the number of active rickettsiae.
mesh_terms: D000818:Animals; D001431:Bacteriological Techniques; D004912:Erythrocytes / Q000276:immunology; D006461:Hemolysis; D012283:Rickettsia prowazekii / Q000276:immunology / Q000302:isolation & purification*; D012756:Sheep / Q000097:blood