Escherichia coli is a bacterium that is naturally present in the intestinal flora. Some strains are pathogens however and can be responsible for gastroenteritis or urinary infections.
Definition: what is Escherichia coli?
Escherichia coli, often abbreviated to E. coli, is a very common intestinal bacterium. It is normally present in the body and takes up 80% of the intestinal flora of most mammals, including humans. Its role is to protect us from the invasion of other bacteria and makes sure that the gastrointestinal system works properly.
Unfortunately, there are strains of E. coli pathogens that cause infections and illnesses such as urinary infections, gastroenteritis or meningitis.
Transmission of Escherichia coli
The starting point of infection is most often in the digestive tract of animals, especially cattle. The contamination is then made orally in humans, by digesting contaminated food. This could be in undercooked meat, untreated milk or fruits and vegetables contaminated by animal waste or if they are not washed properly. Once on the inside of the body, the pathogenic strains colonize the intestinal flora and multiply.
Escherichia coli can also by transmitted via direct contact by hand with contaminated animals or infected people. The incubation period lasts on average around 3 or 4 days after initial contamination, but it can last for a week or more.
Types of Escherichia coli
Strains of E. coli are divided into five categories called pathovars, according to how they function and the symptoms they have:
- Enterohemorrhagic E. coli (EHEC): The EHEC are the most feared because they present the most severe symptoms and are often questioned in epidemics of contaminated foods. They release toxins (called Shiga toxins) which attack the walls of the blood vessels, causing coagulation problems. The ECEH infection is responsible for diarrhea containing blood and can cause hemolytic uremic syndrome (HUS), which is potentially fatal.
- Enterotoxigenic E. coli (ETEC): The ETEC are responsible for traveler’s or tourist’s diarrhea and are a major cause of mild watery diarrhea associated with dehydration in children under the age of 3. The toxins secreted by this strain cause an osmotic diffusion of water towards the intestinal lumen.
- Enteroinvasive E. coli (EIEC): The clinical characteristic signs of the infections by EIEC are a strong fever (up to 40 °C), abdominal cramps, diarrhea as well as the appearance of blood in the stool. Once in the body, they do not give off toxins, but cause the cells to die and trigger a strong inflammatory reaction.
- Enteropathogenic E. coli (EPEC): They are the cause of paediatric gastroenteritis. This is because it is estimated that the strains are pathogenic only under the age of two. Their main risk is dehydration.
- Enteroaggregative E. coli (EAEC): They are responsible for stunted growth and persistent diarrhea. The way they work is still different from the previous forms. The EAEC stick to the intestinal mucosa and form clusters of bricks.
Escherichia coli and urinary infection
Escherichia coli can also be responsible for urinary infections, mainly in women. This is because in women, the urinary tracts are found near to the anus, which renders them vulnerable to an infection by bacteria.
Treatment for Escherichia coli
Treating E. coli is mainly symptomatic. It aims to reduce the dehydration caused by diarrhea. Taking antibiotics is however strongly ill-advised. This is because by destroying bacteria, antibiotics give off dangerous toxins in the body.
How to prevent an infection by E. coli
It is recommended to adhere to certain hygiene rules in order to avoid all contamination by Escherichia coli. It is important to always wash your hands after going to the toilet, changing diapers or after contact with infected people or animals.
When in the kitchen, it is advised to rinse raw vegetables well and peel them, to separate raw foods from cooked foods, to clean equipment after each use and to cook the meat well, especially minced beef.