Lipid A is a component of which bacterial structure and what systemic effect does it mediate?

Lipid A is a component of which bacterial structure and what systemic effect does it mediate?

• A. Lipopolysaccharide (LPS) of Gram-negative bacteria; endotoxin-mediated fever and shock
• B. Teichoic acids of Gram-positive bacteria; cell wall thickening
• C. Outer membrane porins of Gram-negative bacteria; antibiotic resistance
• D. Peptidoglycan layer; autoimmune arthritis

Answer: (A)

Lipid A is the endotoxin component of the lipopolysaccharide that anchors LPS in the outer membrane of Gram-negative bacteria. When LPS is released, Lipid A triggers the host immune system via TLR4, prompting a surge of inflammatory cytokines. This systemic response mediates fever and can progress to septic shock with hypotension. Teichoic acids belong to Gram-positive cell walls and aren’t endotoxins; porins are membrane proteins, not endotoxin-active lipids; and the peptidoglycan layer has structural roles without Lipid A–mediated endotoxin effects.

Lipid A is the endotoxin component of the lipopolysaccharide that anchors LPS in the outer membrane of Gram-negative bacteria. When LPS is released, Lipid A triggers the host immune system via TLR4, prompting a surge of inflammatory cytokines. This systemic response mediates fever and can progress to septic shock with hypotension. Teichoic acids belong to Gram-positive cell walls and aren’t endotoxins; porins are membrane proteins, not endotoxin-active lipids; and the peptidoglycan layer has structural roles without Lipid A–mediated endotoxin effects.