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.[1] Each year, approximately 210 million cases and 380,000 deaths occur, mostly in children, from ETEC.[2] A number of pathogenic isolates are termed ETEC, but the main hallmarks of this type of bacteria are expression of one or more enterotoxins and presence of fimbriae used for attachment to host intestinal cells.
[edit] Enterotoxins
Enterotoxins produced by ETEC include heat-labile enterotoxin (LT) and heat-stable enterotoxin (ST).[3]
- LT is similar to cholera 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.
[edit] 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.[4]
[edit] Prevention and treatment
The most effective method of preventing diarrhea due to ETEC is vaccination. However, vaccines 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.[5] The World Health Organization recommends further research into the development of a vaccine against ETEC.[1] Treatment for ETEC infection includes rehydration therapy and antibiotics, although ETEC is frequently resistant to common antibiotics.[4] 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.
[edit] See also
[edit] References
- ^ a b World Health Organization. Enterotoxigenic Escherichia coli (ETEC).
- ^ World Health Organization. Institute for Vaccine Research. Enterotoxigenic escherichia coli (ETEC).
- ^ Qadri, F.; Svennerholm, A. M.; Faruque, A. S. G.; Bradley Sack, R. (2005). "Enterotoxigenic Escherichia coli in Developing Countries: Epidemiology, Microbiology, Clinical Features, Treatment, and Prevention". Clinical Microbiology Reviews 18 (3): 465–483. doi:10.1128/CMR.18.3.465-483.2005. PMID 16020685.
- ^ a b US Centers for Disease Control and Prevention. Enterotoxigenic Escherichia coli (ETEC)
- ^ Girard, M.; Steele, D.; Chaignat, C. L.; Kieny, M. P. (2006). "A review of vaccine research and development: human enteric infections". Vaccine 24 (15): 2732–2750. doi:10.1016/j.vaccine.2005.10.014. PMID 16483695.
