How E. Coli Bacteria Can Make You Sick and Cause Symptoms: The Taco Bell Ecoli Outbreak

How E. Coli Bacteria Can Make You Sick and Cause Symptoms: The Taco Bell Ecoli Outbreak
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Ecoli Characteristics

Escherichia coli, known as E. coli or simply ecoli, is commonly found in the lower intestines of most warm-blooded organisms. Humans are subject to the ecoli bacteria within 40 hours of birth. Most of the strains are harmless and benefit their hosts by producing vitamin K. By their presence and location they also prevent pathogenic bacteria from taking up residence. However, a number of strains are responsible for different types of infections, most notably food poisoning. The bacterium was discovered in 1885 by a German pediatrician named Theodor Escherich.

Some ecoli characteristics include its lack of retaining crystal violet dye in Gram staining, its process of making ATP aerobically in oxygen, and a lack of ability to create endospores. Ecoli are rod-shaped and are approximately two micrometers long. Ecoli produce lactate, ethanol, acetate, succinate, and carbon dioxide. The bacteria are generally found with hydrogen-consuming organisms that make methane. The optimal temperature for growth of ecoli is 37-degrees Celsius. Most possess flagella that allow them to swim.

Food Poisoning

E. Coli in Electron Microscope

Ecoli bacteria are responsible for the creation of toxins that can cause food poisoning in humans. Usually, this contamination is found on unwashed vegetables and post-slaughter meats. The toxins have varying degrees of severity. Some of the strains can be highly fatal, especially to children and the elderly.

Ecoli harbors enterotoxins which are both heat-stable and heat-labile. This creates two different types of toxins very similar to Vibrio cholerae, the bacterium that causes Cholera. One toxin is responsible for the entry into the cells of a person’s intestines. The other toxin is primarily responsible for preventing cells from absorbing water. This is why food poisoning generally leads to ecoli symptoms like diarrhea.

Further Ecoli Symptoms

E. Coli Flagellum

Other ecoli symptoms include urinary tract infections. According to the U.S. Food and Drug Administration, ecoli is responsible for 90 percent of all urinary tract infections. Fecal bacteria will enter the urethra and spread into the bladder and kidneys. This is more common in women due to the fact that their urethra are shorter.

Meningitis can also result from ecoli infections after birth. If a woman gives birth to a baby while the birth canal is infected, a new born child’s intestines may become colonized. If the ecoli contains the antigen K1, meningitis could develop.

2006 Ecoli Outbreak


One of the largest ecoli bacteria outbreaks in the United States occurred in 2006 with a strain known as O157:H7, a bacterium that causes bloody diarrhea and heavy dehydration. The first phase of the outbreak occurred in September and was primarily associated with spinach. A second outbreak, primarily linked with a Taco Bell ecoli incident, happened in November with tainted iceberg lettuce. This ecoli outbreak was linked to 276 illnesses and three deaths.


About E. Coli: from the MarlerClark blog.


Top to Bottom: E. Coli. (Supplied by the National Institutes of Health; Public Domain;

E. Coli in Electron Microscope. (Supplied by the Agricultural Research Service; Public Domain;

E. Coli Flagellum. (Supplied by the National Science Foundation; Public Domain;

Spinach. (Supplied by Quadell at Wikimedia Commons; GNU Free Documentation License; Creative Commons Attribution ShareAlike 2.0 License;

This post is part of the series: Most Dangerous Bacteria

The genetics of the most dangerous bacteria are complicated. Some examples of these include Clostridium botulinum, staphylococcus aereus, and E. Coli. Staph infection symptoms, symptoms of botulism and ecoli bacteria can be harmful, despite the use of botulinum in Botox.

  1. The World’s Deadliest Poison: Botulinum Toxin
  2. What is Staphylococcus Aureus?
  3. How the E. Coli Bacteria Can Make You Sick