Escherichia coli, commonly known as E. coli, is a type of bacteria. E. coli is a rod-shaped bacterium most commonly found in the small intestines of warm-blooded organisms. The highest concentration of E. coli in human beings is located in the gut, as constituents of normal flora bacteria. E. coli is also located, although less prolifically, in the colon.
The bacteria is thought to have been discovered by German-Austrian pediatrician Theodor Escherich, who found the organism in the fecal matter of healthy patients. Escherich named his discovery Bacterium coli commune, since it was originally found in the colon. After it was discovered, the bacteria underwent numerous reclassifications as scientific understanding of its nature was revised. The original genus, Escherichia, is named after the former Dr. Escherich.
E. coli has a number of variations (or strains). Most strains of the bacteria are neutral, although certain types exist that can make people sick. E. coli is among the most studied organisms in existence, and as a result, many talented scientists have found numerous uses for the bacteria. Whereas the general population often views E. coli as an illness-causing food safety hazard, innovators envision, construct, and execute ambitious projects using the bacteria that benefit multiple facets of society, including medicine.
Beneficial Uses for E. coli
The cellular mechanisms of E. coli are simpler to manipulate relative to more complicated organisms. This is the predominant reason why many researchers continue to search for potential applications of the bacteria. In addition to medicinal discoveries aided by the genetic modification of E. coli, the organism is also being examined for various other projects within public and private sectors.
Genetic engineers often use the organism to produce mass quantities of a manufactured gene due to its less complex molecular structure. Many valuable drugs are produced using the bacterium, including insulin, antibiotics, and other pharmaceuticals.
In recent years, scientists have been using E. coli to manufacture cancer-fighting pharmaceuticals. One research area with noteworthy potential involves engineering E. coli bacteria to recognize and destroy cancer cells. In an ongoing project in Spain, researchers are developing a plan which utilizes E. coli-containing nanobots. These tiny robots would be programmed with instructions to discover, attack and kill cancer cells.
Important uses and applications of E. coli extend beyond medicine. Researchers at the University of Exeter in the UK constructed a biofuel that is potentially one of the most promising replacements yet for fossil fuels. Scientists manipulated the bacteria’s metabolic system to produce fats that mirror the molecules found in gasoline. Additional applications of E. coli include bio-computers, art, rubber manufacturing and others.
The scientific community continuously debates the safety of genetically-engineered E. coli, with many citing concerns about a public health outbreak. To address these fears, statutes now exist that require utilization of weakened strains of E. coli that could not survive long-term in humans.
Illnesses from E. coli
As mentioned, most strains of E. coli are harmless to humans. However, variations of the bacteria do exist that are potentially illness-causing. One specific type of E. coli, O157:H7, is considered to be one of the most hazardous foodborne bacteria in existence. This strain of E. coli can cause bloody diarrhea, kidney failure, and even death.
Potential complications of an E. coli infection are numerous. One complication that is particularly dangerous, hemolytic uremic syndrome (HUS), produces toxic substances that kill red blood cells and results in kidney damage. Treatments often required of HUS are rigorous, including kidney dialysis and blood transfusions. Some patients may require a prolonged period of intensive care to monitor the condition.
O157 strains of a less-severe variety are responsible for the more common outbreaks of E. coli. Sources of O157-type illnesses are most often contaminated food, specifically undercooked ground beef, raw milk, raw milk food products, and raw fruits and vegetables. Contaminated water, airborne fecal particles, and contact with cows, sheep, and goats are also potential causes of such E. coli infections.
Symptoms of E. coli infection include severe and frequently-bloody diarrhea, severe abdominal pain, and vomiting. Fever is quite rare and is usually subtle in nature. HUS symptoms, if exhibited, include reduced production of urine that is often dark or tea-colored as well as paleness of the face. HUS-specific symptoms most commonly appear approximately a week after the onset of general E. coli symptoms.
The duration of illness is generally five to ten days, though the majority of victims feel better within six to eight days. In a small number of cases, the time period is marginally longer.
Recommended treatment includes significant periods of rest and plenty of fluids. A severe onset of symptoms, including incessant diarrhea and vomiting, can result in dehydration. In such cases, it is recommended individuals contact a medical professional who can initiate a modified treatment regimen.
As with most cases of foodborne illness, E. coli can be prevented. Avoidance of foods with a higher risk factor, including undercooked ground beef, unpasteurized milk, unpasteurized milk products, and alfalfa sprouts, can significantly decrease the odds of contracting E. coli-based foodborne illnesses.