**Abstract**

*Escherichia coli* (*E. coli*) has many serotypes. The O157:H7 *E. coli* serotype is the most prominent serotype of enterohemorrhagic *E. coli*. It produces the Shiga toxin, which is one of the most important virulent factors discovered till today and has different subtypes with different antigenic and molecular traits. Consumption of contaminated water, milk or even eating an uncooked raw meat can cause bloody diarrhea that can end up in a life-threatening disease, such as hemolytic uremic syndrome (HUS). This is a condition that affects endothelial cells in the blood vessels and leads to thrombocytopenic purpura (TTP) that can cause blood clots formation in small blood vessels. The *E. coli* O157:H7 can be isolated from patient's stool and be identified by serological tests such as enzyme-linked immunosorbent assay (ELISA) and immunoblotting methods. This special strain of *E. coli* can be used as a biological weapon, as it can be so dangerous and has the ability to spread easily form person to person.

**Keywords:** *E. coli* O157:H7, Stx, STEC, HUS, foodborne illness
