Abstract
Acute gastrointestinal tract infections are among the most common infectious diseases. In the present review, the different methods of diagnosing gastrointestinal infections caused by bacteria, viruses, and parasites are examined. Stool culture is the method of choice for diagnosing bacterial intestinal infections; however, infections caused by Clostridium difficile can be diagnosed by detection of toxins A and B in stools, and infections caused by diarrheagenic Escherichia coli by PCR detection of specific virulence factor genes harbored by several E. coli pathotypes. The techniques used to diagnose viral gastrointestinal infections include detection of viral antigens and nucleic acids. Finally, gastrointestinal infections caused by parasites can be diagnosed by testing for trophozoites and cysts of protozoa, or larvae and eggs of helminths in stools by direct microscopic examination, with concentration techniques, or by specific stains.