Which Enterobacteriaceae mainly produces Shiga-like toxin (verotoxin)?

• A. Klebsiella pneumoniae
• B. E. coli
• C. Salmonella typhimurium
• D. Enterobacter cloacae

Answer: (B)

The primary producer of Shiga-like toxin (also known as verotoxin) among the Enterobacteriaceae is Escherichia coli, particularly certain strains known as Shiga toxin-producing E. coli (STEC). This toxin inhibits protein synthesis by inactivating the 60S ribosomal subunit, which can lead to severe gastrointestinal disease and systemic effects. Some strains associated with this toxin can lead to hemolytic uremic syndrome (HUS), a serious complication affecting the kidneys and causing other systemic issues.

While other bacteria in the Enterobacteriaceae family have their own pathogenic mechanisms and can cause various infections, they do not typically produce Shiga-like toxins. For example, Klebsiella pneumoniae is primarily associated with pneumonia and other serious infections, Salmonella typhimurium is best known for causing gastroenteritis and salmonellosis, and Enterobacter cloacae is associated with opportunistic infections but is not linked to Shiga-like toxin production. Thus, the identification of E. coli as the main producer of this specific toxin highlights its unique pathogenic capabilities within this family of bacteria.