OVERVIEW
Enterotoxigenic Escherichia coli infection is an intestinal infectious disease caused by enterotoxigenic Escherichia coli (ETEC), a group of diarrhea-causing Escherichia coli bacteria recently found in the stools of cholera-like patients in humans, which is one of the major pathogens of “traveler’s diarrhea” in developed countries; it is a common cause of “adult cholera syndrome” and an important pathogen of pediatric diarrhea. It is one of the main pathogens of “traveler’s diarrhea” in developed countries; it is a common cause of “adult cholera syndrome”, and also an important pathogen of pediatric diarrhea, whose incidence rate is second only to that of rotavirus.The disease was first discovered in China in 1982.
Causes
ETEC settles on the surface of the small intestine, does not damage or invade the epithelial cells of the intestinal mucosa, and causes secretory diarrhea by producing enterotoxins. There are more than 10 common serotypes, such as O6, O8, O15, O25, O27, O42, O63, O87, O148, O159 and so on.
There are 2 types of enterotoxins, heat-resistant enterotoxin (LT) and heat-resistant enterotoxin (ST). 1 strain of Escherichia coli can produce both LT and ST, or only 1. LT is a kind of protein, which consists of 1 A subunit and 5 B subunits, with a molecular weight of 85,000, and it can be inactivated at 60℃ for 10 minutes. Its antigenicity and toxicity are similar to that of cholera toxin, and the mechanism of causing diarrhea is also the same as that of cholera toxin, which stimulates the increase of cellular cyclic adenosine monophosphate (cAMP), causing diarrhea due to the persistent overproduction in the small intestine.
Symptoms
1. Incubation period
Generally 0.5-7 days.
2. Symptoms
Secretory diarrhea with watery stools. Accompanied by abdominal cramps, nausea, vomiting, chills, headache, myalgia, rarely fever, the course of the disease 4-7 days. The severity of the disease varies, it can be only mild diarrhea, or it can be severe cholera-like, severe dehydration, acidosis, or even death. Adults are often infected with ST- and LT-producing strains, and pediatrics are more likely to be infected with single ST-producing strains, so adult diarrhea is heavier and lasts longer.
Examination
To confirm the diagnosis, a stool culture of Escherichia coli and a positive test for ST and LT are necessary.
Diagnosis
A proposed diagnosis can be made on the basis of clinical presentation and epidemiologic features.
Differential diagnosis
The main differential should be cholera, followed by viral enteritis and salmonella enteritis.
Complications
Complications of dehydration, water electrolyte disorders, acidosis, etc.
Treatment
This disease has self-limiting tendency, mild cases can be treated without antibiotics, and severe cases can shorten the time of excretion after antibacterial treatment. The treatment of this disease focuses on correcting dehydration, acidosis and hypokalemia. In mild cases, oral rehydration salts and eight-sided montmorillonite (Simida) can be taken, while in severe cases, intravenous rehydration is needed.
Prevention
1. Prevent cross-infection in the hospital.
2. Pay attention to drinking water and dietary hygiene to prevent contamination of water sources.
Prognosis
The prognosis of ETEC enteritis is good. In severe cases, it is like cholera, with moderate to severe dehydration, acidosis and even death.