Platelet Aggregation by Staphylococcal Toxins

Abstract

SummaryAggregation by some staphylococcal toxins resulted in the following observations. Staphylocoagulase in lower concentrations causes aggregation in a similar way as thrombin, whereas in higher concentrations, clotting occurs which is always preceded by quick platelet aggregation. Alpha-hemolysin aggregates human and rabbit platelets, whereas sheep platelets are not affected. Preincubation of susceptible platelets with this toxin, results in their lysis. Betahemolysin causes also aggregation. Leukocidin is inactive. All these phenomena are well visible visually and in the phase contrast microscope. Staphylocoagulase and alpha-hemolysin, when added to the platelet-rich plasma simultaneously with the adenosine diphosphate, interfere and the platelet aggregation is partly inhibited. Pathological aggregation of platelets by bacterial products and its possible significance is discussed.