Escherichia coli, the ubiquitous bacteria linked to the rise in colon cancer in young people

A study recently linked the rise in colon cancer cases in young people to exposure to toxins produced by the Escherichia coli bacteria. In addition, it has been associated with a variety of other complications, such as the dangerous hemolytic uremic syndrome (HUS) and the rare auto-distillery syndrome ( ADS).

In reality, E. coli is a very common bacteria in our environment and even inside our bodies. However, it is mostly harmless , and only in a few cases does it cause serious health problems. There are several types within the same species, and depending on the case, they will have different effects on our bodies.

Severe cases of acute and severe infections

As indicated by theWorld Health Organization , the Escherichia coli bacteria is normally found in the intestines of humans and warm-blooded animals in general, with most strains being completely harmless. However, some strains, such as the one that produces a toxin called Shiga toxin or colitoxin, can be dangerous and cause serious illnesses that are usually contracted by eating contaminated food.

More specifically, Shiga toxin-producing E. coli (named for its resemblance to toxins produced by another bacterial species, Shigella dysenteriae ) thrives in a wide temperature range (between 7 and 50 degrees Celsius, with a preference for around 37 degrees Celsius). It is often present in acidic foods.

In most cases, this strain of E. coli causes an illness characterized by abdominal cramps and diarrhea , which in some cases progresses to hemorrhagic colitis (bloody diarrhea) and even fever and vomiting. However, in a small percentage of people (especially children and the elderly), it can lead to a potentially life-threatening condition called hemolytic uremic syndrome, the main features of which are acute kidney failure, hemolytic anemia, and thrombocytopenia.

Even rarer are cases of E. coli meningitis, which almost always occurs in newborns and causes fever, stiff neck, headache, and neurological signs depending on the severity of the infection.

E. coli and colon cancer: a different bacteria

However, the E. coli strain that the study recently published in Nature has linked to an increase in cancer cases in people under 50 in recent decades is a different one, which produces a different toxin called colibactin.

Unlike colitoxin or Shiga toxin, this compound is genotoxic: that is, it damages the DNA of cells . This is why it can apparently produce mutations in intestinal cells that, over time, can lead to the development of cancer.

These E. coli strains have also been linked to other chronic effects such as intestinal inflammation (which can worsen conditions such as Crohn's disease or ulcerative colitis) or dysbiosis (alterations in the intestinal flora) and have even been linked to some cases of breast cancer (according to a study published in 2023 in Cells ).

Prevention against E. coli

Today, according to the Mayo Clinic (United States), we do not have vaccines or medications against E. coli , so our most effective tool to combat it is prevention.

To avoid contracting a harmful strain of this bacteria, the main precautions include properly cooking food (especially ground meat), ensuring that the milk and juices we drink are pasteurized, thoroughly washing fruits and vegetables, avoiding cross-contamination between foods (by washing utensils, separating raw foods), and washing our hands before and after using the bathroom or handling food.

In the absence of effective medications, treatment for acute E. coli illnesses consists of rest and fluid replacement , and may even require hospitalization in the case of hemolytic uremic syndrome. Regarding the risk of colon cancer, the most effective way to address it is through frequent screening (stool analysis) and colonoscopies when indicated.

References

WHO (2018). E. coli. Accessed online athttps://www.who.int/es/news-room/fact-sheets/detail/e-coli on April 24, 2025.

Díaz-Gay M et al. Geographic and age-related variations in mutational processes in colorectal cancer. medRxiv [Preprint] (2025). DOI: 10.1101/2025.02.13.25322219.

Bernardo G, Le Noci V, Di Modica M, Montanari E, Triulzi T, Pupa SM, Tagliabue E, Sommariva M, Sfondrini L. The Emerging Role of the Microbiota in Breast Cancer Progression. Cells (2023) DOI: 10.3390/cells12151945.

Mayo Clinic. E. coli. Accessed online at https://www.mayoclinic.org/diseases-conditions/e-coli/symptoms-causes/syc-20372058 on April 24, 2025.

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