Last updated date: 03-Apr-2023

Medically Reviewed By

Medically reviewed by

Dr. Lavrinenko Oleg

Originally Written in English

Symptoms of E-coli – A Detailed Guide to E-coli

    Have you ever found that, after eating or drinking something that tasted a bit “off” or which had a slightly unusual smell to it, you found your stomach churning, your temperature rising, you feeling sick and more nauseous with the passing of each hour, and ultimately you found yourself more unwell than you could ever have imagined? If so, you could be feeling the effects of E-coli.

    Within our bodies, naturally, we have a selection of bacteria. Some of these bacterium are good, and some are bad. E-coli is a form of bacteria that is typically located within the digestive tract of living creatures.

    For more information see: Various Colon Infections

    Now, most of these strains of bacteria are harmless and some are even beneficial, yet there are certain strains, including one known as E.coli 0157:H7, which can cause people to become incredibly sick and unwell, and it is this strain of E.coli which we’re going to be looking at today.

    Here is a detailed guide to the symptoms of E.Coli and the various illnesses and issues it can create.


    What exactly is E.coli?


    E.coli, contrary to popular belief, E.coli is not the name of a disease, or food poisoning. As we mentioned earlier, E.coli is actually a strain of bacteria that lives within your digestive tract, primarily in the intestines.  

    It is a bacteria with a rod-shape that is a member of the Enterobacteriaceae family and can thrive in hostile environments with or without oxygen. They are typically found within the intestines of animals and humans.

    Typically, this bacteria is harmless and is actually beneficial as it can help you to digest your food and extract nutrients from it. The problem is that there are certain strains of E.coli bacteria, including the 0157:H7 strain, which can cause extreme side effects and can cause people to become unwell and experience symptoms such as diarrhoea and sickness.

    Hundreds of E. coli strains have been found, causing symptoms ranging from mild, self-limited gastroenteritis to renal failure and septic shock. E. coli's virulence allows it to bypass host defenses and acquire resistance to commonly used antibiotics.

    Enterotoxigenic Escherichia coli (ETEC), enterohemorrhagic Escherichia coli (EHEC), also known as Shiga toxin-producing Escherichia coli (STEC), and EHEC/STEC, enteroinvasive Escherichia coli (EIEC), enteropathogenic Escherichia coli (EPEC), and enteroaggregative Escherichia coli (EAEC) (EAEC). Clinical disease will be used to define extraintestinal ailments.


    E. coli infection Symptoms

    E. coli infection Symptoms

    In order to diagnose E. coli infection, a thorough medical history and physical examination are required. The start, length, and intensity of symptoms, as well as any relieving and aggravating variables, such as any over-the-counter drugs tried, may help differentiate it from other intestinal disorders. It's also critical to distinguish between watery and bloody diarrhea, as well as to inquire about recent travel and nutrition history, which might point to E. coli as the source of the sickness.

    The most prevalent bacterial cause of traveler's diarrhea is ETEC, and diagnosis requires a high level of clinical suspicion. Symptoms often appear more than 16 hours after consuming infected food, although diarrheal disease caused by germs other than E. coli might appear considerably sooner.

    If a patient has an extraintestinal E. coli infection, it's critical to inquire about previous infections and assess the potential of drug-resistant organisms. Indwelling equipment, such as ureteral stents or Foley catheters, should be considered when a patient comes with symptoms associated with cystitis.

    The physical exam helps doctors to determine the severity of an ailment. Patients with vital signs that imply systemic illness should be treated in a location that can offer comprehensive treatment, such as a hospital-based emergency department or in-patient unit. All patients should have their mucous membranes and skin turgor evaluated for clinical indicators of dehydration. All individuals suspected of having E. coli infection should have their hearts and lungs checked.

    Finally, a focused exam should complement the patient's history by revealing other findings that might help guide patient management. A complete abdominal exam should be conducted on patients with intestinal and genitourinary symptoms, whereas patients suspected of having sepsis caused by E. coli should have a full physical exam.


    Does E.coli primarily cause food poisoning?

    Cause food poisoning

    People often associate E.coli with food poisoning, and while it is true that this strain of bacteria can cause you to suffer with the symptoms of food poisoning, it can also lead to other serious illnesses such as pneumonia and urinary tract infections.

    In fact, the vast majority of UTIs (estimated to be as high as 95%) are caused by E.coli bacteria. This is because, as it is located in the bowels, it isn’t too far from the urinary tract and as they’re all connected it can easily find its way over there and start reaping havoc.


    How and why does E.coli make us sick?

    E.coli make us sick

    Okay, so, you’ve eaten something that you shouldn’t have eaten, you feel as if your stomach is starting to gurgle, and hours later you’re dealing with abdominal cramps, fever, chills, sickness, nausea, diarrhoea, and plenty of other nasty symptoms and you’re worried you’re suffering with food poisoning brought on by E.coli. But how does this bacteria make us so unwell?

    For more information see: Food Poisoning - Causes, Symptoms, Types, and Treatment

    It doesn’t matter if you’re 6-ft 6 inches tall, and weigh 320-pounds, microscopic strains of bacteria such as E.coli can bring even the biggest and healthiest of individuals to their knees. E.coli makes us sick by producing a toxin which is known as Shiga.

    Shiga toxin causes damage to the lining of the intestine and is produced by strains of E.coli known as ‘Shiga-Toxin Producing E.coli’ or STEC for short. The main culprit is our friend E.coli 0157:H7, which is the one that can really make you sick and can potentially even kill people.

    Some of the main life-threatening side effects associated with this bacteria include:

    • Internal bleeding
    • Seizures
    • Renal failure
    • Cardiovascular failure

    If you experience any of these symptoms, regardless of what you believe the cause may be from, you should always speak to a doctor and seek medical advice.


    What are the main causes of infection through E.coli poisoning?

    Infection through E.coli poisoning

    Despite E.coli being present in our bodies, if we ingest even the tiniest amount of harmful bacteria like the E.coli strain we mentioned earlier, it can make us incredibly sick.

    Some of the primary ways in which people become infected with E.coli bacteria include the following:


    Drinking unpasteurized milk

    Lately, farm stores and artisanal cafes and eateries have started offering customers natural, untreated and unpasteurized milk which has come straight from the cow.

    In most instances, this is perfectly fine and perfectly healthy, but there are certain risks. You see, milk is typically pasteurized, which means it is heated at a very low temperature for a prolonged period of time to kill off any harmful toxins, parasites, or other organisms in the milk that shouldn’t be there, such as E.coli.

    If you drink unpasteurized milk, there is a risk that you could ingest a harmful strain of this bacteria which would then make you very sick.

    The bacteria could get into the milk from the udder of the cow, or even from milking equipment and if it gets inside your body you will be at risk of a whole variety of symptoms like those we looked at earlier.


    Processed meat  

    Processed meat  

    Processed meat or ground meat can be another potential carrier of harmful E.coli bacteria that is responsible for making you sick.

    It may sound gross, but when meat is ground up and processed, sometimes you find that bacteria living in the intestines of the animals can find its way into the meat.

    Ground and processed meat is often a prime culprit for E.coli because usually they are made from a selection of different animals.

    Again, all it takes is a very miniscule amount to get into your body and you could become extremely unwell.


    Contaminated water

    In terms of health, water is arguably the healthiest beverage you could wish for. Filtered water, or ideally mineral water is packed full of healthy minerals and as it is such a great source of hydration, it’s easy to see why it is considered the healthiest beverage in existence.

    However, some water can make us incredibly unwell thanks in part to the fact that it contains E.coli bacteria.

    Stagnant water or contaminated water in a pool, pond, or lake could contain this bacteria and if we accidentally swallowed a mouthful of this water we’d find ourself at risk.


    From animals

    While visiting an animal park, farm, or petting zoo is a great way to spend an afternoon, if you are around animals you could potentially find yourself being exposed to E.coli bacteria.

    The bacteria could be on the fur of the animals, so if you pet the animals and don’t wash your hands thoroughly afterwards, it could then be transferred onto your food, and it could then make its way inside you.


    From fruits and vegetables

    From fruits and vegetables

    Fruits and vegetables are, without a shadow of a doubt, amongst the healthiest types of food in existence, yet they too could potentially carry harmful E.coli bacteria.

    More often than not, these foods are contaminated with water containing E.coli bacteria, so again, this is certainly something to watch out for.


    From other people

    Finally, if you come into contact with somebody carrying E.coli bacteria, they could potentially pass the bacteria on to you, which in turn would make you very sick.

    Parents often get sick after cleaning up after a child that has been infected with E.coli, as it may be found in vomit or other bodily secretions. If the parent doesn’t thoroughly wash their hands, even the tiniest traces of E.coli could still be present and if they enter the body that’s all they need to multiply and make you very ill.


    E. coli diagnosis

    E. coli diagnosis

    Because diarrheal sickness is commonly self-limiting, routine laboratory examination is not usually necessary in well-appearing individuals. However, in patients with worrying signs or symptoms that imply systemic disease, they may corroborate clinical suspicion and guide therapy. A baseline complete blood count (CBC) and a basic metabolic panel (BMP) should be collected for patients with suspected EHEC/STEC infection.

    Patients with chronic diarrheal disease, systemic signs or symptoms, or dysentery should have their stool cultures taken. Because pathogenic E. coli cannot be distinguished only on the basis of appearance, additional biochemical tests are required.

    coli is a spore-free, flagellated, and facultatively anaerobic bacteria. E. coli can digest lactose and generate indole naturally, and before PCR-based techniques, they were discovered using selective culture medium. E. coli is traditionally cultured on MacConkey agar, a lactose-containing culture medium. During metabolism, E. coli creates indole, and bacterial growth on MacConkey agar with indole production is diagnostic for E. coli.

    PCR has recently been used to identify non-O157:H7 EHEC strains that do not digest sorbitol. These isolates will continue to be detected more often as PCR-based techniques become more widely available. Stool cultures for E. coli, Salmonella, Shigella, and Campylobacter should be performed on all patients with inflammatory diarrhea who have been outside of the United States.


    Are there any treatments for E.coli-related illnesses?

    treatments for E. coli

    Treatment is determined by both the strain and the sickness. Treatment of a patient with an intestinal infection caused by E. coli. coli treatment begins with symptomatic treatment. Diarrhea may be a very upsetting experience for sufferers. Rehydration and antidiarrheals are the pillars of treatment for mild illness, according to experts.

    When tolerated, oral rehydration is suggested as first-line treatment for all patients with diarrheal disease and is equally effective as intravenous hydration (IV). When patients cannot tolerate oral intake, IV hydration is suggested. Antimotility drugs like bismuth-subsalicylate and loperamide are used to relieve distressing symptoms.

    Antibiotics are not indicated as a first-line therapy for E. coli-related diarrhea in the majority of patients due to unpleasant side effects and the risk of antibiotic resistance. Antibiotics may be appropriate for individuals with severe illness (e.g., more than six stools per day, fever, dehydration requiring hospitalization, diarrhea lasting more than seven days, or bloody diarrhea). E. coli diarrheal disease is now treated with rifaximin, azithromycin, and ciprofloxacin. Antibiotics are not indicated for individuals suspected of having EHEC/STEC, especially in children and the elderly, due to the increased risk of hemolytic uremic syndrome.

    In order for your doctor to make a diagnosis of E.coli-related sickness, a sample of your stool will need to be sent to a laboratory to be analysed and examined.

    As far as treatment options go, this mainly depends on the type of E.coli infection or illness that you are suffering with. Some for example, can be treated with antibiotics as they can shorten the life of the bacteria and reduce the amount of time that you experience adverse symptoms and side effects.

    However, as we mentioned Shiga toxin producing E.coli earlier, if you are suffering with this particular strain of E.coli, you should NOT consume any antibiotics as they can actually boost the production of Shiga toxin in your body and make your symptoms even worse.

    As sickness, perspiring, and diarrhoea are often associated with E.coli illnesses, this can result in you losing a lot of fluids and electrolytes, which will need to be replaced. Drink plenty of water and consider a sugar-free electrolyte beverage or medication.

    The good news is that in most cases, an infection caused by a harmful strain of E.coli will go away by itself, usually in a matter of days, though some extreme cases can last longer than a week.


    Differential Diagnosis

    A variety of pathogens can cause intestinal disease. Viruses, such as norovirus and rotavirus, are the most prevalent causes of watery diarrhea, although bacteria, such as Staphylococcus aureus, Bacillus cereus, and Vibrio cholerae, can also cause it.

    Shigella spp., Salmonella spp., Campylobacter jejuni, and Yersinia enterocolitica, among other etiologies, should be considered in patients with inflammatory or bloody diarrhea. Extraintestinal infections, as mentioned earlier, can be caused by a number of viruses and bacteria, depending on the sickness.



    The majority of diarrheal diseases, including those caused by E. coli, have a good prognosis. Watery diarrhea caused by E. coli infections is usually self-limited, but even when medications are necessary, the sickness is curable and individuals recover completely. Children who acquire HUS as a result of EHEC/STEC have the highest risk of morbidity and death.

    Approximately 4% of children with EHEC/STEC-induced HUS will die, and the remaining 5% will suffer serious long-term consequences, such as end-stage renal disease and stroke. Another 20 to 30 percent will experience various complications; those who do not experience these complications usually recover completely within two weeks.

    Comorbid factors influence the prognosis of individuals who develop E. coli extraintestinal infections. E. coli does not indicate a bad prognosis by itself. Patients with E. coli extraintestinal infections, on the other hand, are typically sicker at the start. E. coli, for example, is a common cause of spontaneous bacterial peritonitis (SBP) in patients with ascites .



    Complications of Escherichia coli

    Dehydration is a danger for patients who develop diarrheal disease, although it may frequently be avoided with proper hydration and early symptomatic care. Chronic diarrhea and irritable bowel syndrome are long-term problems that affect a tiny percentage of people. Patients with EHEC/STEC diarrhea are at risk of developing hemolytic uremic syndrome, which affects children under the age of five and adults over the age of 60.


    Prevention of Escherichia coli

    Escherichia coli are bacteria found in the environment, foods, and intestines of people and animals. The types of E. coli that can cause illness can be transmitted through contaminated water or food, or through contact with animals or people.

    Practice proper hygiene, especially good handwashing.

    • After using the restroom and changing diapers, wash your hands thoroughly.
    • Before and after preparing or consuming food, wash your hands thoroughly.
    • After coming into touch with animals or their habitats, wash your hands thoroughly (at farms, petting zoos, fairs, even your own backyard).
    • Before preparing and giving bottles or meals to an infant or toddler, touching an infant or toddler's mouth, or handling pacifiers or other items that go into an infant or toddler's mouth, wash your hands well.
    • Clean any things that enter the mouths of newborns and toddlers (such as pacifiers and teethers).
    • Use an alcohol-based hand sanitizer with at least 60% alcohol if soap and water aren't accessible (check the product label to be sure). In some cases, these alcohol-based treatments can immediately reduce the quantity of germs on hands, but they are not a substitute for soap and running water.



    Escherichia coli is a common bacteria found in the human gastrointestinal system that can cause infections in hospitals. The organism is the most common cause of urinary tract infections, as well as the most common cause of diarrhoea in those traveling internationally. Diarrhea produced by E. coli is frequently self-limiting.

    coli infections can be avoided by washing hands often, washing fruits and vegetables thoroughly, and properly cooking meat. When visiting locations with poor sanitation, such as many developing countries, disease can be avoided by drinking filtered water and fully preparing meals, or washing fresh fruits and vegetables in pure water. Prophylactic antibiotics can considerably reduce disease when infection cannot be prevented or when patients are at high risk for diarrheal sickness sequelae.