A 50 -year-old woman presented at the emergency room complaining of urinary urgency and flank pain. Microscopic examination of a urine sample was done and gram staining was done. Prior to initiation of antibiotic therapy, she abruptly developed fever, chills, and delirium. Hypotension and hyperventilation rapidly followed. These observations suggest that the patient is responding to the release of which bacterial component?

The patient is most likely suffering from septic shock. In two thirds of patients, septic shock results from infection with gram-negative bacteria, such as Escherichia coli, Klebsiella, Enterobacter, Proteus, pseudomonas and Bacteroides. Septicaemia is more common in persons whose resistance is already compromised by an existing condition. The gram-negative bacteria release endotoxin or heat-stable, lipopolysaccharide (LPS) components of the outer membranes. The main physiologic effects of LPS endotoxin are fever, hypotension, and thrombosis, collectively referred to as septic shock. Death can result from multiple organ failure. Gram-positive bacteria release exotoxins that can elicit a shock syndrome, but response is usually not as severe as that of gram-negative septic shock.