Endotoxin, a lipopolysaccharide found in the outer membrane of gram-- negative bacteria, has been implicated in the pathogenesis of septic shock. The exact role of this toxin in human disease, however, remains controversial and other bacterial toxins may significantly contribute to the pathophysiology of this often fatal syndrome. This study compares the levels of bacteremia, endotoxin concentrations, cardiovascular dysfunction and mortality caused by different clinical isolates of gram-negative bacteria in a well-described canine model of septic shock. The study is designed to determine if all gram-negative bacteria produce significant endotoxin release and whether endotoxemia in a gram-negative septicemia uniformly correlates with the morbidity and mortality of the infection. These experiments have implications for ongoing efforts to develop cross-- protective anti-endotoxin antibodies for the treatment of gram-negative sepsis. The preliminary studies on this project have been completed, and the 1st manuscript from this work is pending publication (Chest 1990, in press). Further investigation into this area are proceeding with Dr. Hoffman as the principle investigator.