Diarrheagenic Escherichia coli in Adult
Enterotoxigenic E coli (ETEC) – The leading cause of traveler's diarrhea worldwide. Transmitted by food and/or water contaminated with animal or human feces. Especially prevalent in children from developing countries and also a cause of traveler's diarrhea. This causes profuse watery diarrhea and abdominal cramping. Other associated symptoms include fever, nausea, vomiting, chills, loss of appetite, headache, muscle aches, and bloating. Symptoms develop 1-3 days after exposure and last for 3-4 days.
Enteropathogenic E coli (EPEC) – These strains have a characteristic attaching mechanism that allows them to adhere to enterocytes of the gut. This attachment causes induction of signal transduction pathways that alter water and electrolyte secretion, leading to diarrhea. This mostly affects children under 6 months of age in developing countries. Associated symptoms include vomiting. Dehydration and malnutrition are potentially deadly side effects, especially in children. Adults are less likely to be symptomatic.
Enteroinvasive E coli (EIEC) – Uncommon, related to Shigella. Usually begins with watery diarrhea, which may progress to bloody diarrhea.
Shiga toxin-producing E coli (STEC), also called enterohemorrhagic E coli (EHEC) – Included in this group is E coli O157, which is known to cause large outbreaks. STEC is found in the gut of ruminant animals such as cattle, goats, sheep, and deer. Infections occur when humans are exposed to human or animal feces with STEC. High-risk foods include unpasteurized milk, unpasteurized apple cider, and soft cheeses made with raw milk. Adults and children are equally affected, with more severe disease seen in young children and the elderly. Symptoms include abdominal cramping, diarrhea (often bloody), vomiting, and fever. There is an incubation period of 3-4 days after exposure. The duration of disease is typically 5-7 days. A serious complication seen in 5%-10% of affected individuals is hemolytic uremic syndrome (HUS), which can cause irreversible kidney damage.
Enteroaggregative E coli (EAEC) – This strain expresses adherence fimbriae and a flagellin, which causes the release of interleukin-8. Also associated with a cytotoxin that causes mucosal destruction. It is a common cause of acute diarrheal illness in adults and children in the developing world. Sporadic outbreaks have occurred in developed countries. Adults with human immunodeficiency virus (HIV) may be particularly susceptible.
Diffusely adherent E coli (DAEC) – A cause of diarrhea in children, less so in adults. Strains express Afa/Dr adhesins that allow binding to gut enterocytes. Children are thought to be more susceptible than adults due to lack of maturity of the intestinal epithelial barrier.
A04.4 – Other intestinal Escherichia coli infections
111839008 – Intestinal infection caused by Escherichia coli
Differential Diagnosis & Pitfalls
This is generally the differential of acute infectious diarrhea, though some E coli infections have a more chronic presentation:
- Adenovirus – Associated with cold-like symptoms.
- Rotavirus – Typically causes disease in infants and young children.
- Cryptosporidium – Adults with HIV/AIDS, children younger than 1 year of age.
- Norovirus – Associated with outbreaks on cruise ships.
- Vibrio cholerae – Affects children from endemic areas such as sub-Saharan Africa, the Middle East, China, Mexico, Cuba, Haiti, and Australia.
- Other enteric bacterial etiologies: Yersinia, Salmonella, Shigella, Campylobacter
- Clostridioides difficile – Associated with antibiotic use and hospitalization.
- Giardia – Associated with poor sanitary conditions and lack of water treatment facilities.
- Cyclospora – Opportunistic infection in immunocompromised individuals.
- Entamoeba histolytica – More common in developing countries due to poor sanitation. Endemic to India, Africa, Mexico, parts of Central and South America.
- Cytomegalovirus – Causes diarrhea in the immunosuppressed individual (eg. HIV/AIDS), solid organ transplant recipients, patients undergoing chemotherapy