Disseminated intravascular coagulation associated with Staphylococcus aureus septicemia is mediated by peptidoglycan-induced platelet aggregation

Disseminated intravascular coagulation (DIC) may complicate severe septicemia caused by Staphylococcus aureus. S. aureus can induce spontaneous platelet aggregation in vitro, the rapidity and degree of which correlates with the severity of DIC in patients with sepsis. Purified peptidoglycan from DIC isolates aggregated human platelets in the presence of staphylococcal protein A with significantly shorter aggregation times than did peptidoglycan from non-DIC isolates. Purified teichoic acid from DIC and non-DIC isolates failed to aggregate platelets in vitro, or in vivo in guinea pigs but inhibited the peptidoglycan-induced aggregation in a dose-response manner. These studies suggest that peptidoglycan may mediate S. aureus-induced spontaneous platelet aggregation in vitro and DIC in vivo. The variability among strains of S. aureus to induce DIC and platelet aggregation may depend on the unique composition of their peptidoglycan and perhaps also the extent of exposure or availability of cell wall teichoic acid.