What is Escherichia Coli Infections (E.Coli)

E coli is one of the most frequent causes of some of the many common bacterial infections, including cholecystitis, bacteremia, cholangitis, urinary tract infection (UTI), and traveller’s diarrhoea, and other clinical infections such as neonatal meningitis and pneumonia.
The genus Escherichia is named after Theodor Escherich who isolated the type species of the genus. E coli is a major facultative inhabitant of the large intestine.

Statistics on Escherichia Coli Infections (E.Coli)

In the US: E coli is the leading cause of both community-acquired and nosocomial UTI. As many as 50% of women have had at least one episode of UTI in their lifetime. E coli causes 12-50% of nosocomial infections, and E coli causes 4% of diarrhoeal disease.
Internationally: In tropical countries, EPEC is an important cause of childhood diarrhoea. ETEC causes 11-15% of cases of traveller’s diarrhoea for those visiting developing countries and 30-45% of cases of traveller’s diarrhoea for those visiting Mexico. EAggEC causes 30% of cases of traveller’s diarrhoea.

Risk Factors for Escherichia Coli Infections (E.Coli)


  • Urinary tract infections: pregnant or sexually active women, men with prostatic hypertrophy, and patients with urinary catheters are at particular risk.
  • Neonatal infections – colonisation with E. coli K1
  • Gastroenteritis
    – Travellers to countries with poor hygienic standards.
    – Eating meat, especially ground beef, that has not been cooked sufficiently as well as consumption of sprouts, lettuce, salami, unpasteurized milk and juice, and swimming in or drinking sewage-contaminated water can lead to a diarrhoeal illness.
  • Septicaemia: infection with E.coli at another site (eg gastroenteritis, UTI).


Progression of Escherichia Coli Infections (E.Coli)


  • Urinary Tract Infections: E. coli originates in the colon. The bacteria can cause UTIs after contaminating the urethra, and subsequenly ascend to the bladder and upper renal tract.
  • Gastroenteritis: There are different strains of E. coli – Enterotoxigenic (ETEC), enteroinvasive (EIEC), enteropathogenic (EPEC), enterohaemorrhagic (EHEC) and enteroaggregative (EAggEC). Most strains cause watery diarrhoea with vomiting and crampy abdominal pain, although the EIEC and EHEC strains can cause a more serious picture with bloody stools, dysentery and potentially haemolytic uraemic syndrome (EHEC strains). Haemolytic uraemic syndrome leads to renal failure, thrombocytopaenia, and haemolytic anaemia.


How is Escherichia Coli Infections (E.Coli) Diagnosed?

FBC: may show increased white cell count due to infection. Blood film may reveal haemolysis in the Haemolytic Uraemic syndrome (HUS).
U+Es: may be abnormal due to dehydration or show acute renal failure in HUS.
Stool culture

Prognosis of Escherichia Coli Infections (E.Coli)

The prognosis depends on the specific diagnosis; therefore, no generalizations can be made. Urinary tract infections and gastroenteritis are conditions with a very good prognosis and full recovery within several days, unless complicated by septicaemia or haemolytic uraemic syndrome.

How is Escherichia Coli Infections (E.Coli) Treated?

Most persons recover without antibiotics or other specific treatment in 5-10 days. There is no evidence that antibiotics improve the course of disease, and it is thought that treatment with some antibiotics may precipitate kidney complications. Antidiarrheal agents, such as loperamide (Imodium), should also be avoided.
Hemolytic uremic syndrome is a life-threatening condition usually treated in an intensive care unit. Blood transfusions and kidney dialysis are often required. With intensive care, the death rate for hemolytic uremic syndrome is 3%-5%.

Escherichia Coli Infections (E.Coli) References

[1] Division of Bacterial and Mycotic Diseases.
[2] eMedicine.
[3] Johnson JR: Virulence factors in Escherichia coli urinary tract infection. Clin Microbiol Rev 1991 Jan; 4(1): 80-128.
[4] Jonas M, Cunha BA: Bacteremic Escherichia coli pneumonia. Arch Intern Med 1982 Nov; 142(12): 2157-9.

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