<prompt> A 4-year-old boy gives the history of bloody diarrhea and now hospitalized for oliguria and hypeension. With which organism is he most likely infected?Clostridium perfringensSalmonella typhiEnteroinvasive E. coliShiga toxin-producing E. coli  <response>: The case is descriptive of hemolytic uremic syndrome associated with infection with E. coli O157:H7. This strain of E. coli produces phage-associated Shiga toxins Stx-1 andor Stx-2 that are functionally and antigenically similar to that produced by Shigella dysenteriae. None of the other organisms listed are associated with hemolytic uremic syndrome, although some do cause a bloody diarrhea. C. perfringens causes watery diarrhea. 