All you need to know about E-coli infection

December 22 06:56 2022 Print This Article

Overview

Escherichia coli is a type of bacterium that is found in the intestines of human-beings and animals. When faeces containing E coli contaminates food, soil and water, and the same is consumed by humans or animals, it creates a vicious cycle of contamination and infection. E coli infection leads to intestinal disorders, but in some people, it can progress towards serious complications. In this article, we will learn all the facets of E coli infection.

Introduction

Escherichia Coli is a type of bacterium that is found in the intestines of human-beings and animals. Some strains of E coli are harmless and do not cause any conditions. But some strains such as the E. coli O157:H7 produce a toxin called Shiga that can cause intestinal infection. Such strains are called Shiga Toxin producing E Coli or STEC.

Strains of E coli that cause intestinal illness

• Entero-toxigenic Escherichia coli (ETEC): This is generally found in rural communities or urban slums where availability of clean drinking water, as well as good sanitation, are challenges. This is generally responsible for traveller’s diarrhoea in adults and dehydrating diarrhoea in infants.
• Entero-hemorrhagic Escherichia coli (EHEC): This type is abundantly found in ground beef and contaminated fruits or vegetables, which when consumed leads to severe intestinal infection. Several outbreaks of infection caused by this strain have happened, across the world.
• Entero-pathogenic Escherichia coli (EPEC): This type causes watery diarrhoea. It comes from consuming fruits or vegetables that are unhygienically produced or stored. They can also transmit from person-to-person contact.
• Entero-aggregative Escherichia coli (EAEC): Like ETEC, EAEC also causes traveller’s diarrhoea. But unlike ETEC, this strain is found even in places where sanitation and clean drinking water are available.
• Entero-invasive Escherichia coli (EIEC): A rare strain that looks less like E coli and more like Shigella, another bacterium that causes intestinal infections.
• Diffusely adherent Escherichia coli (DAEC): A newer strain that requires more research. This subtype envelops the surface of cells which is unlike any other strain of E coli. It causes diarrhoea in young children.

Causes of Ecoli infection

Contaminated Soil and Food:

• Meats: When animals are slaughtered for meat, the E coli from their intestines get mixed up with the cuts of meat. Further, when meat from different animals is ground together (as in the case of ground beef), E coli contamination is certain. When such contaminated meal is not cooked properly (E coli is killed by heat), then E coli infection is highly likely.
• Raw or unpasteurized milk: E coli found on the cow’s udder gets transferred to the milking equipment and hence the milk. Drinking such contaminated raw milk leads to E. coli infection. Some soft cheeses are made from raw milk, which increases the risk of contamination, and hence infection when consumed.
• Unpasteurized fruit juices sold in cans or tetra-packs, and unpasteurized apple-cider sold in bottles or cans, increase the risk of E coli infection.
• Fruits and vegetables: Rain-water runoff or irrigation-water runoff from animal farms have animal faeces in them, most of the time. These contaminate the soil in the vicinity. When fruits and vegetables are grown on such contaminated soil, the fresh produce may contain E coli. Consuming such fruits and vegetables without washing them thoroughly increases the risk of infection.
• Unsanitary food-handling at restaurants and homes. This includes cross-contamination. That is, mixing up cooked food and raw food. For example, when cooked food is placed on cutting boards contaminated with E coli after vegetables have been cut on them.
• Consuming raw fish or raw seafood
• Consuming foods that you, or a restaurant, or a food manufacturer, has not stored at the right temperature 

Contaminated water

E coli from human and animal faeces can make its way into water bodies like lakes, rivers, ponds, and even swimming pools. In many coastal cities, untreated sewage is let out into the ocean. When such contaminated water is accidentally swallowed while swimming, or through drinking water, E coli infection is highly likely.

Contaminated hands

People who change diapers of infants, who handle animals in farms or pet-animals at home, who handle fresh produce like fruits or vegetables, or meat in butcheries and slaughterhouses, all have plenty of E coli on their hands. When such people do not wash their hands thoroughly and touch food, people consuming that food will get infected. Also, if such people touch or come in physical contact with other human beings, the E coli gets transferred to the latter’s hands. When these people do not wash their hands before eating, they end up ingesting E coli along with food. However, it’s good to know that E coli does not spread by droplet infection which is how most viruses, that cause respiratory infections, spread.

Risk Factors

Not everyone who ingests E coli into their bodies ends up with E coli infection. So, needless to say, some people are more at risk of infection than others. These include:

• People who travel often to places or countries where availability of clean drinking water and good sanitation is an issue.
• New-born infants and younger children (below 7 years of age)
• The elderly, with or without any major ailments
• People with weakened immune systems, like those suffering from HIV, diabetes, cancer, and pregnant women
• Eating certain foods: Undercooked meat dishes; unpasteurized milk, unpasteurized fruit-juices or apple-cider; soft cheeses made from raw milk.
• Time of the year: For no clear reason, monsoon months increase the risk of E coli infections. This could be because of more contaminated water runoffs to water bodies.
• Decreased stomach acid levels. Stomach-acid acts as a barrier against some pathogens including E coli. Certain medications like esomeprazole, pantoprazole, lansoprazole and omeprazole are known to reduce stomach-acid levels, so people taking such medications are at high risk of E coli infection.

Symptoms

Mild to moderate infection

• Sudden, severe and watery diarrhoea, where the stools may range from watery to bloody
• Pain, cramps and tenderness in the stomach
• Nausea and vomiting, in some people
• Gas and a bloated-up feeling
• Loss of appetite
• Fatigue and low energy levels
• Fever

Severe infection

• Blood in the urine
• Reduced urine output
• Dull skin
• Bruising or bruised look on the skin
• Dehydration

Complications from severe infection

• Urinary tract infection: Women are at high risk of this if they wipe from back to front after using the toilet. This is because E coli from faeces may enter the urethra due to close proximity between the anus and urethra.
• Infection in the abdomen and pelvis
• Pneumonia
• Bacteraemia caused by bacteria entering the bloodstream
• Meningitis, in which E coli bacteria cross the blood-brain barrier and infect brain tissue
• Haemolytic uremic syndrome (HUS): A serious condition in which red blood cells get damaged. This can lead to kidney failure which is life-threatening for children and older adults.

When to see a doctor

Rush to a doctor if you are having one or more of the following:

• You have diarrhoea that does not seem to improve after 2 days for children, and 4 days for adults
• There is fever along with diarrhoea
• Pain in the abdomen in-spite of a visit to the toilet
• There is blood in the stools, or the stools is slimy (contains pus)
• There has been repeated vomiting for over 12 hours
• You have come back from international travel and have diarrhoea
• There are symptoms of dehydration, such as low urine output, severe thirst, or dizziness
• You keep vomiting or visiting the toilet, after consuming liquids

Diagnosis

Diagnosis is very simple. A sample of the stools is sent to a laboratory to confirm or rule out the presence of E coli, and if confirmed, what is the extent of the problem and type of E coli involved. The stools culture will also confirm the presence of Shiga or any of the toxins produced by E coli strains.

Treatment

Unlike many other infections, E coli infection will go away on its own and not everyone requires medication.

• Stay hydrated: The person should not get dehydrated, and must consume plenty of fluids.
• Get rest: The person should take as much rest as possible, taking time off from work and personal pursuits.
• Watch out: The person should constantly watch out for symptoms of severe infection as mentioned earlier.
• Take medication: Only in some cases will the doctor prescribe anti-diarrhoeal medication. Anti-biotics are not given, to reduce the risk of anti-biotic resistance and other side-effects.

Reviewed by Dr Suresh S Venkita, Group Medical Director, Kauvery Hospitals

Kauvery Hospital is globally known for its multidisciplinary services at all its Centers of Excellence, and for its comprehensive, Avant-Grade technology, especially in diagnostics and remedial care in heart diseases, transplantation, vascular and neurosciences medicine. Located in the heart of Trichy (Tennur, Royal Road and Alexandria Road (Cantonment), Chennai, Hosur, Salem, Tirunelveli and Bengaluru, the hospital also renders adult and pediatric trauma care.

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