Enterotoxigenic Escherichia coli
Encyclopedia
Enterotoxigenic Escherichia coli (ETEC) is a type of Escherichia coli
and the leading bacterial cause of diarrhea
in the developing world, as well as the most common cause of traveler's diarrhea
. Each year, approximately 210 million cases and 380,000 deaths occur, mostly in children, from ETEC. A number of pathogen
ic isolates are termed ETEC, but the main hallmarks of this type of bacteria
are expression of one or more enterotoxin
s and presence of fimbriae
used for attachment to host intestinal cells.
(LT) and heat-stable enterotoxin
(ST).
due to ETEC is vaccination. However, vaccine
s against ETEC are not yet available for populations where ETEC is endemic. There are currently available treatment options against traveler's diarrhea
, specifically against illness due to cholera
. Data from natural history studies of ETEC infections in children in developing countries suggest that immunization against ETEC early in life may be an effective preventive strategy. The World Health Organization
recommends further research into the development of a vaccine against ETEC. Treatment for ETEC infection includes rehydration therapy and antibiotics, although ETEC is frequently resistant to common antibiotics. Improved sanitation is also key, since the transmission of this bacterium is fecal contamination of food and water supplies, one way to prevent infection is by improving public and private health facilities. Another simple prevention of infection is by drinking factory bottled water, this is especially important for travelers and traveling military.
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
and the leading bacterial cause of diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
in the developing world, as well as the most common cause of traveler's diarrhea
Traveler's diarrhea
Traveler's diarrhea , is the most common illness affecting travelers. An estimated 10 million people—20% to 50% of international travelers—develop it annually. TD is defined as three or more unformed stools in 24 hours passed by a traveler, commonly accompanied by abdominal cramps, nausea, and...
. Each year, approximately 210 million cases and 380,000 deaths occur, mostly in children, from ETEC. A number of pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
ic isolates are termed ETEC, but the main hallmarks of this type of bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
are expression of one or more enterotoxin
Enterotoxin
An enterotoxin is a protein toxin released by a microorganism in the intestine. Enterotoxins are chromosomally encoded exotoxins that are produced and secreted from several bacterial organisms. They are often heat-stable, and are of low molecular weight and water-soluble...
s and presence of fimbriae
Fimbria (bacteriology)
In bacteriology, a Cilli is a proteinaceous appendage in many Gram-negative and some Gram-positive bacteria that is thinner and shorter than a flagellum. This appendage ranges from 3-10 nanometers in diameter and can be up to several micrometers long...
used for attachment to host intestinal cells.
Enterotoxins
Enterotoxins produced by ETEC include heat-labile enterotoxinHeat-labile enterotoxin
Heat-labile enterotoxin is a type of labile toxin found in Escherichia coli that is inactivated at high temperatures.It acts similarly to the cholera toxin by raising cAMP levels through ADP-ribosylation of the alpha-subunit of a Gs protein leading to the constitutive activation of adenylate cyclase...
(LT) and heat-stable enterotoxin
Heat-stable enterotoxin
Heat-stable enterotoxins are secretory peptides produced by some bacterial strains, such as enterotoxigenic Escherichia coli which are in general toxic to animals.These peptides keep their 3D structure and remain active at temperatures as high as 100oC....
(ST).
- LT is similar to choleraCholeraCholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae. The main symptoms are profuse watery diarrhea and vomiting. Transmission occurs primarily by drinking or eating water or food that has been contaminated by the diarrhea of an infected person or the feces...
toxin; it increases the level of cAMP in intestinal cells, and this causes an increase in electrolyte and water excretion (diarrhea).
- ST stimulates production of cGMP, also leading to increased fluid excretion and diarrhea.
Presentation
Because enterotoxic E. coli strains are non-invasive, they do not cause inflammation. Infection with ETEC can cause profuse watery diarrhea with no blood nor leukocytes and abdominal cramping. Fever, nausea with or without vomiting, chills, loss of appetite, headache, muscle aches and bloating can also occur but are less common.Prevention and treatment
The most effective method of preventing diarrheaDiarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
due to ETEC is vaccination. However, vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
s against ETEC are not yet available for populations where ETEC is endemic. There are currently available treatment options against traveler's diarrhea
Traveler's diarrhea
Traveler's diarrhea , is the most common illness affecting travelers. An estimated 10 million people—20% to 50% of international travelers—develop it annually. TD is defined as three or more unformed stools in 24 hours passed by a traveler, commonly accompanied by abdominal cramps, nausea, and...
, specifically against illness due to cholera
Cholera
Cholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae. The main symptoms are profuse watery diarrhea and vomiting. Transmission occurs primarily by drinking or eating water or food that has been contaminated by the diarrhea of an infected person or the feces...
. Data from natural history studies of ETEC infections in children in developing countries suggest that immunization against ETEC early in life may be an effective preventive strategy. The World Health Organization
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
recommends further research into the development of a vaccine against ETEC. Treatment for ETEC infection includes rehydration therapy and antibiotics, although ETEC is frequently resistant to common antibiotics. Improved sanitation is also key, since the transmission of this bacterium is fecal contamination of food and water supplies, one way to prevent infection is by improving public and private health facilities. Another simple prevention of infection is by drinking factory bottled water, this is especially important for travelers and traveling military.
See also
- DiarrheaDiarrheaDiarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
- Diarrheal diseases
- Infectious diarrheaInfectious diarrheaInfectious diarrhea or Contagious diarrhea may be defined as diarrhea caused by an infection of the digestive system by a bacterium, virus, or parasite that results in frequent bowel motions producing excessive amounts of liquidy feces.-Causes:...
- Traveler's diarrheaTraveler's diarrheaTraveler's diarrhea , is the most common illness affecting travelers. An estimated 10 million people—20% to 50% of international travelers—develop it annually. TD is defined as three or more unformed stools in 24 hours passed by a traveler, commonly accompanied by abdominal cramps, nausea, and...
- GastroenteritisGastroenteritisGastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water...