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E. Coli 0157:H7 (cont.)

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What causes E. coli infection?

There are over 700 strains (serotypes) of E. coli. Most of the strains of E. coli are normal inhabitants of the small intestine and colon and do not cause disease in the intestines. (They are non-pathogenic.) Nevertheless, these non-pathogenic E. coli can cause disease if they spread outside of the intestines, for example, into the urinary tract (where they cause bladder or kidney infections), or into the blood stream (sepsis). Other E. coli strains (enterovirulent E. coli strains or EEC) cause "poisoning" or diarrhea even though they usually remain within the intestine by producing toxins or intestinal inflammation. There are four to six groups (some researchers combine groups) of E. coli serotypes that comprise EEC. Their names are derived from descriptions of the characteristics that separate them from the other groups.

  • EHEC (enterohemorrhagic E. coli)
  • ETEC (enterotoxigenic E. coli)
  • EPEC (enteropathogenic E. coli)
  • EIEC (enteroinvasive E. coli)
  • EAEC (enteroadherent E. coli)
  • EAggEC (enteroaggregative E. coli)

E. coli were first isolated by T. Escherich in 1885 and were named after him. The over 700 serotypes are identified by small antigenic changes in their surface "O" antigens (lipopolysaccharides or molecules on the bacterial surface of gram-negative bacteria), for example E. coli 0157 or E. coli 055. These serotypes are identified by immunological tests using antibodies to the antigens. E coli strains are further distinguished by "H" protein antigens (different types of flagella that make the bacteria motile). Consequently, a particular E. coli strain can be identified as H, followed by a number, and this identifier is added to the "O" name; for example, E. coli 0157:H7. Although this name designation seems complicated, researchers and clinicians use these antigenic identifiers to track specific E. coli strains that cause outbreaks of disease.

As discussed previously, E. coli strain, E. coli 0157:H7 is notorious for its potential to cause complicated disease in humans; the remainder of this article will focus on this E. coli strain. However, it is important to remember other types of E. coli produce similar if not identical problems and they too, will be addressed in this article; the newest serotype causing problems is E. coli 0145.

Is E. coli 0157:H7 contagious?

E. coli 0857:H7 is an infection, and is contagious. It can be spread from person to person by contamination with feces of food or water then is eaten.

Medically Reviewed by a Doctor on 9/25/2017


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