E coli bacteria. Picture taken from a public domain


The O157:H7 strain is arguably the worse strand of E. coli out there. This strand produces a Shiga toxin and is know as a STEC. The shiga toxin is also known as verotoxin. The gene designation for shiga toxin produced by E. coli O157:H7 is stx1 with the name Shiga Toxin 1. This toxin has a molecular weight of 68,000 da. It is made up of one molecule of an A subunit which is responsible for the action of the toxin. Another 5 molecules of subunit B binds to cell types within the host. Sample of E. coli O157:H7 (STEC). Photo taken from public domain. Photo taken by Microrao.

The incubation period for STEC is 3 to 5 days. The symptoms will last around 1 to 3 days. A person who has been infected by typically has watery diarrhea (often times bloody), vomiting, and a low grade fever.

Outbreaks of STEC have been associated with consumption of undercooked beef (mostly ground beef), raw milk, apple juice, contaminated water, red leaf lettuce, alfalfa, sprouts, and jerky.  This bacteria can also come from poultry, pork,  and lamb.

STEC can be spread from person to person from fecal-oral transmission. This is especially common in child care centers and nursing homes.

Want to learn more about two other common food borne bacteria that can make you sick? Follow these links:
Salmonella enteritidis
Clostridium botulinum

Now that we have learned more about this bacteria click here for some fun fast facts.