E. coli gut infection linked to bowel cancer

A common type of gut bacterium may increase a person's chance of developing bowel cancer, according to a study published in the journal Nature.

The bacterium is a type of E. coli infection, present in up to one in five people, scientists believe. It releases a toxin which experts say can damage the cells that line the bowel, potentially turning some cells cancerous over time.

There are around 42,000 new cases of bowel cancer each year in the UK.

HOW DANGEROUS MIGHT IT BE?

The researchers suspect it may contribute to a minority of bowel cancer cases - one in 20 or five in every 100 but more research is needed to confirm the link.

There is no routine test for the bacterium currently, and it is not clear yet that people who have it will be at heightened risk.

In some people it may live in the bowel and cause no issue.

It is not the first infection to be linked with cancer, however. HPV is a virus that causes cervical cancer and H pylori infection is associated with stomach cancer.

IS IT THE SAME AS FOOD POISONING?

No. This particular E. coli strain is not one of the ones linked to food poisoning outbreaks.

There are lots of different types of E. coli. Many are part of the normal gut flora the trillions of bacteria that naturally live in the bowel.

WHAT DID THE STUDY FIND?

The team, from The Netherlands, the UK and the US, used miniature replicas of the human gut, grown in the lab, to test the effects of the toxin on cells.

They then compared the damage seen with more than 5,000 bowel cancer samples taken from patients and found identical patterns or "fingerprints" of DNA damage in around 5% of the samples.

WHAT ARE BOWEL CANCER SYMPTOMS?

- a persistent change in bowel habit - going more often, with looser stools and sometimes tummy pain

- blood in the stools without other symptoms, such as piles

- abdominal pain, discomfort or bloating always brought on by eating - sometimes resulting in a reduction in the amount of food eaten and weight loss

Most people with these symptoms do not have bowel cancer, but the NHS advice is to see your GP if you have one or more of the symptoms and they have persisted for more than four weeks.

Source: NHS UK