Not every patient with fever and diarrhea requires work-up - use clinical judgement
Consider work-up for patient with:
Fever
Toxic appearance
Diarrhea lasting >3 days
Blood or pus in stool
Immunocompromised patients with presumed infectious diarrhea
Bacterial stool culture
N.B. - In many labs, stool culture tests for Salmonella, Shigella, and<unk> 
Stool ova and parasites if concern for parasitic infection
Consider C. difficile PCR if patient has risk factors
Fever
Toxic appearance
Diarrhea lasting >3 days
Blood or pus in stool
Immunocompromised patients with presumed infectious diarrhea
N.B. - In many labs, stool culture tests for Salmonella, Shigella, and<unk>
Campylobacter jejuni
Infectious:
Salmonella
Yersinia enterocolitica
Shigella
Clostridium difficile 
Shiga toxin-producing E. coli
Clostridium difficile