What Does E. Coli Poop (diarrhea) Look like?

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What is E. coli? When does it cause diarrhea?

E. Coli is a bacteria that is present in abundance inside your colon and stool. Under normal conditions, E. coli doesn’t cause diarrhea or poop changes.

However, the non-pathogenic E. coli can turn into pathogenic E. coli by genetic mutations.

Also, you can get infected by E. coli through (reference):

  • Contaminated water.
  • Contaminated food.
  • Contact with an infected person.
  • Contact an infected animal or pet.

The three commonest sources of E. coli are (reference):

  • Undercooked meat or poultry.
  • Unpasteurized milk or juice.
  • Unpasteurized soft cheese.

The symptoms of E. coli (such as diarrhea, fever, and vomiting) often appear 3 to 4 days after ingesting the contaminated food or contacting an infected person.

Five main strains of E. coli are known to cause diarrhea and stool changes:

  • ETEC (Enterotoxigenic E. coli): causes severe watery diarrhea.
  • EPEC (Enteropathogenic E. coli): It mainly affects children under six months; it causes severe watery diarrhea, vomiting, and dehydration.
  • EHEC (Enterohemorrhagic E. coli): causes large outbreaks of bloody diarrhea. It is also responsible for hemolytic uremic syndrome (acute diarrhea, anemia, jaundice, and kidney failure).
  • EIEC (Enteroinvasive E. coli): it starts with watery diarrhea. Then, it may progress into bloody diarrhea and dysentery.
  • EAEC (Enteroaggregative E. coli): Causes acute or chronic watery diarrhea (without blood).

Types of E. coli Poop (according to color and contents):

The most common causes of food poisoning and related diarrhea in the USA are (reference):

  • Viruses (commonest): Affecting about 5.5 million cases per year.
  • Bacteria (Including E. coli): affecting around 3.6 million per year.
  • Parasites: affecting about 233 Thousand per year.

E. coli can cause many types of diarrhea and stool changes depending on the strain causing diarrhea.

1. Yellow watery poop (diarrhea).

The most common stool change with E. coli is diarrhea (loose or watery stool). The E. coli poop with watery diarrhea often becomes yellowish due to the speeding up of the stool inside the intestine (no time for the poop to be processed into its normal brown color).

Diarrhea often starts acutely with abdominal pain, vomiting, and maybe fever.

Common E. coli strains that cause yellow watery diarrhea (reference):

  • ETEC (Enterotoxigenic E. coli).
  • EPEC (Enteropathogenic E. coli).
  • EAEC (Enteroaggregative E. coli).

2. E. Coli Bloody diarrhea.

Certain strains of E. coli may cause outbreaks of severe bloody diarrhea (the poop is loose or watery with fresh blood and mucus).

The most common strains that cause bloody poop include:

  • Enterohemorrhagic E. coli (EHEC).
  • Enteroinvasive E. coli (EIEC).

The EHEC strain O157:H7 is the most famous strain that causes large outbreaks of bloody diarrhea.

3. E. Coli dysentery (blood, mucus, and tenesmus).

Some strains of E. coli may cause typical dysentery (severe urge to poop with blood and mucus in stool), similar to bacillary dysentery.

The main type of E. coli that causes dysentery is the Enteroinvaisive strains (ETEC). These strains produce severe inflammation and damage to the color lining, similar to the shigella bacteria (the bacteria responsible for bacillary dysentery).


Symptoms of E. Coli Diarrhea (VS Viral gastroenteritis).

The symptoms of E. coli diarrhea are often in the form of acute gastroenteritis. The most common cause of gastroenteritis is viruses (stomach flu), not bacteria.

Viral gastroenteritis (as with norovirus and rotavirus) is generally milder than E. coli gastroenteritis.

Because viral gastroenteritis is very common and the symptoms are similar, you must know the differences between the two conditions.

The symptoms of E. coli include:

  • Onset: is often one to eight days after contacting an infected person or eating contained food.
  • Diarrhea: it is often severe, watery, with yellow poop. The diarrhea is often severe and very frequent but may be mild in some cases.
  • Bloody poop: some strains of E. coli may cause blood (reddish) watery diarrhea.
  • Dysentery: Diarrhea with blood and mucus with severe urgency and a sense of incomplete evacuation occurs with certain strains such as Enteroinvasive E. coli (EIEC).
  • Severe stomach cramps.
  • Nausea.
  • Vomiting.
  • Fever (may become high grade).
  • Signs of dehydration may occur in severe cases such as extreme thirst, scanty urine, shortness of breath, dizziness, fainting attacks, etc.
  • Rarely, some people may develop jaundice, pallor, and scanty urine after the onset of diarrhea (hemolytic uremic syndrome).
Type Viral Gastroenteritis Bacterial GE
1- Site Usually affects the stomach and small intestine. Affects the colon.
2- Diarrhea. Watery, mild Bloody, mucoid, more severe.
3-Vomiting Usually present Rarely occur.
4- Cramps mild Severe
5- Fever Low grade High grade
6- Anorexia Mild or not present severe.

Does E. coli poop have a specific smell?

E. coli poop may smell offensive. However, it is not a specific sign of the infection as foul-smelling diarrhea is more common among other conditions such as giardia infection, celiac disease, and food intolerance.

Diagnosis of E. Coli in Poop.

The diagnosis of E. coli in poop during diarrhea depends on a combination of:

  • Specific clinical features (severe watery or bloody diarrhea, high fever).
  • Stool culture.
  • Molecular tests to diagnose the specific strain.
  • Exclusion of the other causes of watery or bloody diarrhea, such as shigellosis (bacillary dysentery) and viral gastroenteritis.

Treatment of E. coli diarrhea.

Once diagnosed, your doctor will prescribe treatment depending on:

  • Your age.
  • The severity of diarrhea/ presence of blood in the stool.
  • The presence of signs of dehydration.
  • The presence of vomiting or fever.

Mild infections of E. coli diarrhea often need supportive treatments such as good hydration and nutrition without the need for antibiotics.

A. Antibiotics:

Antibiotics are not recommended in Sigha toxin-producing E. coli (STEC) because they may increase the risk of hemolytic-uremic syndrome (reference).

However, your doctor will prescribe antibiotics if there are:

  • Severe, frequent diarrhea (not due to STEC): more than six stools per day.
  • High fever.
  • Sings of dehydration.
  • Blood diarrhea.
  • Prolonged diarrhea for seven days or more.
  • High-risk groups as patients with low immunity.

The 3 Best antibiotics for E. coli diarrhea include:

  • Azithromycin.
  • Ciprofloxacin.
  • Levofloxacin.

The best approach is to give antibiotics according to the culture and sensitivity testing of the stool.

B. Good hydration.

Drinking frequent small amounts of fluid or bland juice may help. Severe cases of dehydration (with frequent diarrhea and vomiting) may need oral rehydration solutions or intravenous fluids.

C. Nutrition.

Eat bland, easy-to-digest foods that improve diarrhea, such as the BRAT diet (bananas, rice, apple sauce, and toast).

Eating smaller, more frequent meals is more helpful than eating one or two large meals daily.

If the vomiting is frequent, your doctor may prescribe intravenous fluids.

D. Other treatments

  • OTC antidiarrheals such as loperamide.
  • OTC antispasmodics.
  • Antipyretics such as paracetamol (Tylenol®) or Ibuprofen (Advil®).
  • Anti-emetics if there is severe vomiting or nausea (such as ondansetron).