In Shiga toxin–producing E. coli infections, which toxin is associated with severe disease and HUS?

• A. Shiga-like toxin
• B. Cholera toxin
• C. Diphtheria toxin
• D. Tetanus toxin

Answer: (A)

Shiga-like toxin is the toxin linked to the severe disease and HUS seen with Shiga toxin–producing E. coli infections. It is a ribosome-inactivating cytotoxin that inactivates the 60S ribosomal subunit by removing a specific adenine from the 28S rRNA, halting protein synthesis and causing cell death. This endothelial damage, especially in the renal microvasculature, leads to the hemolytic anemia, low platelets, and acute kidney injury that define hemolytic uremic syndrome. By contrast, other toxins listed cause different effects: cholera toxin triggers massive watery diarrhea by increasing cAMP in intestinal cells; diphtheria toxin inhibits protein synthesis with mucosal and systemic effects; tetanus toxin blocks inhibitory neurotransmitter release, causing spastic paralysis.