Overview of intestinal pathogenic E. coli

Pathovar Clinical picture Patients
Enterohemorrhagic E. coli (EHEC) watery/bloody diarrhea, hemorrhagic colitis, HUS all ages, especially children under 5 years
Enteropathogenic E. coli (EPEC) watery diarrhea especially infants
Enteroaggregative E. coli (EAEC) persistent diarrhea, dystrophia in infants, diarrhea in immunocompromised patients of all ages all ages, especially immunocompromised
Enteroinvasive E. coli (EIEC) watery diarrhea all ages
Enterotoxigenic E. coli (ETEC) traveller's diarrhea, watery diarrhea all ages, alle Altersgruppen, infants diarrhea in developing countries
Adherent-invasive E. coli (AIEC) Crohn's disease all ages

Enterohemorrhagic Escherichia coli (EHEC)
Enterohemorrhagic Escherichia coli (EHEC) belong to the intestinal pathogenic E. coli  that cause watery/bloody diarrhea, the hemorrhagic colitis and the extraintestinal hemolytic uremic syndrome (HUS). The major virulence factor is Shiga toxin. The most common serotype detect in severe human diseases is E. coli O157:H7. Most frequently, the pathogens were ingested via contaminated food. Currently, there is no specific therapy. Due to the low number of EHEC in stool samples of HUS patients, a valid diagnosis is frequently only possible in specialized laboratories.

EHEC-associated diarrhea
The majority of EHEC infections are asymptomatic. After an incubation period of 3 to 8 days, initially watery (later frequently bloody) diarrhea occurs. Abdominal cramps are a frequent symptom; especially in children fever or vomiting are noticed. Severe courses of infections are frequent in very young children, elderly and immunocompromised patients. In 10 to 20 % of the patients, a hemorrhagic colitis occurs. EHEC infections of immunocompetent adults exhibit frequently only mild diarrhea or no symptoms at all.

Patients are infectious as long as EHEC bacteria are detected in stool samples. Usually, detection of EHEC ends 1 to 2 weeks after beginning of symptoms, however, although not typical, shedding of EHEC can be prolonged in single cases.