Background: Diarrhea is an important cause of morbidity and mortality, particularly in developing countries. Enteric gram-negative bacteria, especially Shigella, Salmonella, Escherichia, and Campylobacter plays a key role in the occurrence of diarrhea. The present study aimed to determine the prevalence and importance of four bacterial genera in the incidence of diarrhea in Shahid Beheshti Hosp...