Which Enterobacteriaceae produces Shiga-like toxin primarily?

The correct answer is E. coli, specifically certain strains of it, such as Shiga toxin-producing E. coli (STEC), including E. coli O157:H7. This particular type of E. coli is known for producing Shiga-like toxin, which can cause severe intestinal disease, including hemorrhagic colitis, and can lead to serious complications like hemolytic uremic syndrome (HUS).

Shiga-like toxin inhibits protein synthesis in host cells, which is a key mechanism in its pathogenicity. This characteristic makes certain strains of E. coli particularly notable among the Enterobacteriaceae family.

Other bacteria listed don't produce Shiga-like toxins or are typically associated with different forms of disease. Klebsiella pneumoniae is primarily known for causing pneumonia and other infections, Salmonella typhimurium is associated with gastroenteritis and does not produce Shiga-like toxin, and Enterobacter cloacae is generally involved in various opportunistic infections. None of these are recognized for producing the severe toxins that E. coli strains do.