What is the most likely diagnosis for a patient with watery diarrhea, abdominal pain after a cookout, progressing to fever, bloody diarrhea, and AKI?

The presentation of watery diarrhea that progresses to bloody diarrhea, accompanied by abdominal pain, fever, and acute kidney injury (AKI), suggests a diagnosis of Enterohemorrhagic Escherichia coli (EHEC), particularly the strain known as O157:H7. EHEC is commonly associated with undercooked beef, unpasteurized dairy products, and contaminated produce, making it plausible in the context of a cookout.

One of the hallmark features of EHEC infection is its ability to cause hemorrhagic colitis, which explains the transition from watery to bloody diarrhea. The bloody diarrhea is a result of the toxin produced by EHEC, known as Shiga toxin, which can lead to significant intestinal damage. In some cases, EHEC infection may also lead to hemolytic uremic syndrome (HUS), a condition characterized by AKI, hemolytic anemia, and thrombocytopenia, correlating with the renal involvement observed in this patient.

Other types of infections, while they may present with diarrhea and sometimes fever, do not typically lead to the same combination of symptoms or the severe sequelae like AKI associated with EHEC. For instance, Salmonella infection usually causes a