Three consecutive stool cultures from a 25 year-old male pat…

Three consecutive stool cultures from a 25 year-old male patient produced little normal fecal flora on MacConkey and Hektoen enteric agars.  Colonies produced on CIN agar displayed “bulls-eye” colonies after 48 hours of incubation.  The patient had been suffering from enterocolitis with fever, diarrhea and abdominal pain for 2 days.  What is the most likely identification of this gram negative rod?