Escherichia coli

Since November, the Centers for Disease Control and Prevention has confirmed 52 cases of Escherichia coli infection across 9 states linked to Chipotle restaurants. Of those infected, 20 have been hospitalized, 47 confirm eating at a Chipotle restaurant, and 21 cases are genetically similar.


E. coli O157:H7. Public Health Image Library. Centers for Disease Control and Prevention.

Escherichia coli is a rod-shaped bacterium that is mostly found in the lower intestine of warm-blooded organisms. Most E. coli strains are harmless and are actually in a symbiotic relationship with their hosts, while others are parasites that infect their hosts. Some of the serotypes can cause serious issues and lead to food poisoning, urinary tract infection, and other digestive problems causes by food contamination. The harmless strains are part of the normal bacteria living in the digestive tract and helps break down foods eaten by the host. This E. coli strain also produces vitamin K and protects the intestines from other pathogens.

Identifying an E. coli infection is not easy, as the symptoms are very similar to that of food poisoning and early signs of the flu however ruling out E. coli is simple. In order to test for E. coli, a stool sample must be collected, and then can be sent to the lab for testing. Precaution should also be taken to test any foods or water for E. coli contamination, and the local government should be notified.

There is no treatment for an E. coli infection, however we can treat the complications from the infection such as drinking water to fight dehydration from diarrhea is suggested. Diarrhea is the number one symptom that doctors should be aware of in the case of an E. coli infection. Diarrhea is a serious issue that leads to hundreds of deaths a year if not treated properly.

E. coli and other related bacteria make up about .1% of bacterium in the digestive tract. This bacterium is transmitted through fecal-oral interaction. E. coli cells are only able to exist outside a host for a small amount of time, but long enough for this bacteria to be an indicator species of water contamination. This ability to survive for an amount of time outside a host has sparked a medical interest in extending the time this bacterium can survive on its own. E coli is one of the model prokaryotes that are used in both biotechnology and microbiology studies with recombinant DNA. This bacterium is easily manipulated and grown within a laboratory setting, making it an ideal experimental cell and has been aggressively studied for the past half century.

Most of the infections from the recent outbreak have been located in the North West such as Oregon and Washington. The strain of E. coli that has been isolated is the O26 strain, which is a shiga-toxin producing strain. This strain typically infects within 4 days of ingestion and is characterized by bloody diarrhea and abdominal cramps.


Centers for Disease Control and Prevention. 2015. Multistate Outbreak of Shiga toxin-producing Escherichia coli O26 Infections Linked to Chipotle Mexican Grill Restaurants. December 4 2015.

Center for Disease Control and Prevention. Public Health Image Library. 2006. Gram Negative Eschericha Coli. Janice Haney Carr.