Pseudomonas aeruginosa Compared with Escherichia coli Produces Less Endotoxemia: Results (3)
Overall mortality differed markedly among the study groups (Table 1). All dogs receiving E coli at doses of 7 and 14 x 109 CFU/kg survived. Pseudomonas aeruginosa at a dose that was nonlethal for E coli (14 X 109 CFU/kg) resulted in a significant mortality, 11 of 32 animals (p<0.01; Fisher exact test). Total body ionizing radiation of200 cGy increased mortality from 0 to 60 percent (p<0.01; Fisher exact test) in animals infected with E coli (14 X 109 CFU/kg).
Plasma Endotoxin Concentrations and Quantitative Hemodynamic Changes
Endotoxin concentrations determined during septic shock for each of the study groups are shown in Table 2. As previously reported, dogs implanted with sterile clot did not have development of significant endotoxemia compared with baseline values. Dogs infected with E coli and P aeruginosa had detectable endotoxemia on day 1 after surgery that decreased but remained significantly elevated (p<0.01) at 48 hours. In the four E coli dogs tested at earlier time points, plasma endotoxin concentrations at 6 and 12 hours after clot implantation were similar (p = NS) to day 1 values. Pseudomonas aeruginosa infection resulted in very low or undetectable concentrations of plasma endotoxin at these early time points.