E. coli bacterial Infection – Causes, Symptoms, and Treatments

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E.coli or Escherichia coli is a common bacterial species that are found in the intestine of humans and animals, environment and foods. Most E.coli strains are harmless and develop a symbiotic relationship with humans.

The E.coli plays a major role in the field of genetic engineering. These bacteria have high efficiency in taking up any new DNA molecules. E.coli is preferred for protein production, as they grow very fast. These bacterial species also have the ability to express proteins at high levels.


However, there are certain types of E.coli that can be harmful to humans. When they infect humans, the most common symptom is diarrhoea and urinary tract infection. Prolonged infection can lead to respiratory illnesses like pneumonia and other health issues.

When the bacteria infect the animals, and humans consume such contaminated food, it can infect the humans. Among the strains, the Shiga toxin-producing E.coli causes significant foodborne diseases.

The bacterial strain produces toxins that are similar to toxins produced by the organism Shigella dysenteriae, which leads to diarrhoea. These toxic bacteria can be killed when the foods are cooked properly. The causes and symptoms of E.coli are further discussed in the blog.

Causes of E.coli

The E.coli infection can be caused due to common habits like not heating the food to proper temperature and consuming contaminated water and food. The infection can also spread from one infected person to another through personal contact.

Eating Contaminated Foods

Consuming contaminated food is a common mode of infection. E.coli infection can be commonly seen in animal meat like beef and mutton. When the animal is slaughtered for meat, the bacteria from the intestine can be present on the meat.

When humans consume contaminated meat without proper cooking, it can cause infection to humans. The common strain present in contaminated is E. coli O157:H7.

The strain is commonly present in salami, hamburgers, unpasteurised apple cider and cheese that is made from raw milk.

When a person handles food with contaminated hands, it can pass the infection to the food and the person consuming it can be affected.

According to the World Health Organisation (WHO), there is an increasing number of outbreaks of E.coli infection with the consumption of fruits and vegetables like sprouts, spinach, coleslaw and lettuce.

This can be due to contamination with animal faeces during cultivation. Animal faeces have also been reported to contaminate water bodies.

Contaminated Water

Water contamination can occur in human and animal stools. It happens when the groundwater is polluted, and humans get infected. When contaminated water is used for irrigation, it can contaminate vegetables and fruits.

Consumption of contaminated fruits and vegetables without proper cleaning can lead to E.coli infection. Private water sources like wells can be a point of the outbreak. This may be due to improper disinfection or no disinfection at all.

The water supply in rural areas is most likely to have a contaminated water supply. There have been many reports regarding the outbreak of E.coli in rural areas due to contaminated water consumption.

Personal contact

E.coli infection can easily pass from person to person, especially when they travel. When adults or children do not practise self-hygiene, it can easily spread to other people.

An outbreak of E.coli infection can occur when petting animals in zoos and barns. The infection can easily spread from one child to children at the school level.

Children who do not wash their hands after using the restroom and consume food with contaminated hands can lead to E.coli infection.

Another common point of E.coli infection is in public swimming pools. When public swimming pools are not properly maintained, it can lead to infection. Sometimes, even in chlorinated water, the contamination can spread.

Symptoms of E.coli

Some of the common symptoms of E.coli infection are listed.

Stomach pains

E.coli infection, most of the time, infects through food. The first symptom of E.coli infection is stomach pain and intestinal coli. This might be caused due to the disturbance of the stomach and  intestinal flora.

The bacteria make a toxin that damages the inner lining of the stomach wall. This can lead to painful stomach cramps.


Another common symptom of E.coli infection is diarrhoea. Often diarrhoea can be bloody and watery stools.

Diarrhoea can lead to dehydration. So, it is important to keep yourself hydrated during the infection period. This will also help the infection to flush out of the body.


The infection will make your body weak and tired.

Loss of appetite

The infection can cause loss of appetite. E.coli causes severe stomach pain, which reduces a person’s appetite.


Vomiting is also one of the common symptoms. Vomiting can make a person dehydrated and tired.

Low fever

Fever can be one of the symptoms of E.coli infection. Usually, the fever will not go beyond 101 Fahrenheit. People infected can get better within 5-7 days.

However, there are cases reported to be fatal. This can happen when people do not hydrate themself.

Treatments of E.coli

There is no specific treatment available for E. coli infection. Certain things can be followed to relieve symptoms.


Rest will be required as infected people will not have energy. They will have fatigue and severe stomach cramps. So proper rest and sleep are required to recover well.

Drink Fluids

E.coli infection can lead to fluid loss and dehydration. So, it is important to keep hydrating yourself. ORS powder can help with dehydration. Consuming healthy food and nutritious food is also important to battle fatigue.

Risk factors of E.coli

The infection can occur to anyone. However, some people with weakened immunity are more susceptible to these types of infections. Some of the common risk factors are listed below.


Children are more susceptible to E.coli infection. Children might experience significant complications.

Older people also tend to contact this infection often. As they are ageing, their immune system may not be as alert. So, they can contact the infection easily.

Weakened immune systems

People with a weakened immune system can be more susceptible to all infections.

Eating certain types of food

Foods like meat, unpasteurised milk and cheese from raw milk may contain E.coli. Consuming such foods can lead to infection.

Time of year

E.coli requires a warm temperature to grow. Its optimal growth temperature is 37℃. Usually, the infection of E.coli can be seen during monsoon seasons. It can easily spread from one person to another during the monsoon.

Decreased stomach acid levels

The concentrated acids and enzymatic juices present in our stomach offer a line of defence against harmful organisms. Sometimes, E.coli infection can result from reduced stomach acid levels in humans.

When to see a doctor?

Consult your doctor when you have the following symptoms.

  • If your fever persists for more than three days,
  • Severe dehydration,
  • Fatigue and
  • Bloody diarrhoea.


E.coli infection is a common infection. The common symptoms include bloody diarrhoea, dehydration, fatigue and loss of appetite. The symptoms settle down after five days. If the symptoms do not settle down, it is recommended to consult a doctor.

Personal hygiene can help prevent such infections. E.coli infection occurs when consuming contaminated meat. So, always consume foods that are cooked properly and cover the foods properly to avoid any contamination.


What are the health risks of E. coli?

E.coli infection causes bloody diarrhoea, fatigue, dehydration, stomach pain, nausea and vomiting accompanied by a slight fever.

How do you get an E.coli infection?

E.coli infection can be caused when consuming animal foods that are contaminated and not cooked properly. Swimming in pools contaminated with E.coli can also spread from one person to another.

Is E. coli harmful to humans?

Most E.coli strains are not harmful to humans. However, some strains can be pathogenic, like Shiga toxin-producing E.coli.

How long does E.coli last in the body?

It takes about 5-10 days for the E.coli to leave the human body. The symptoms settle from the fifth day of infection.


The Information including but not limited to text, graphics, images and other material contained on this blog are intended for education and awareness only. No material on this blog is intended to be a substitute for professional medical help including diagnosis or treatment. It is always advisable to consult medical professional before relying on the content. Neither the Author nor Star Health and Allied Insurance Co. Ltd accepts any responsibility for any potential risk to any visitor/reader.

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