Following urinary tract infection associated with extraction of a bladder stone, a 64-year-old woman developed gram-negative septicemia. Which statement is true for gram-negative bacterial septicemia?

Many of the adverse changes can be accounted for by endotoxin release. Escherichia coli is the most common organism involved in gram-negative septicemia, followed by Klebsiella, Aerobacter, Proteus, and Pseudomonas. The cardiac index is high, peripheral resistance is decreased, and CVP is low to normal. The most common conditions leading to gram-negative sepsis are those of the urinary tract, followed by respiratory and biliary tract and abdominal visceral infections. Endotoxins are lipopolysaccharide complexes. The lipid A portion is probably responsible for the toxicity.