Colon cancer risk increased by Salmonella exposure

A Salmonella infection is a common bacterial disease that affects the intestinal tract

Do people who are more frequently exposed to non-typhoidal Salmonella have an increased risk of colon cancer? Researchers from Leiden University Medical Center (LUMC) and the University of Illinois jointly conducted a study to find an answer to this question. Initial study results suggest that non-typhoidal Salmonella may increase the risk of colon cancer by contributing to one stage in the multistep process of cancer formation.

The researchers’ findings were published in Cell Reports Medicine.

A Salmonella infection is a common bacterial disease that affects the intestinal tract. Humans are commonly exposed to non-typhoid Salmonella, primarily through livestock and through the consumption of livestock-derived foods, such as eggs and meat.

Typhoid Salmonella, which causes typhus, infects 10-20 million people each year and causes an estimated 130,000 deaths worldwide. Non-typhoid Salmonella infections are more common and less fatal, but lead to an estimated 153 million cases of diarrhea and vomiting and 57,000 deaths worldwide each year.

Salmonella and the development of cancer
Typhoid Salmonella infection has previously been linked to gallbladder cancer. This is because the bacteria allow for one step in the multi-step process of cancer formation. Epidemiological studies have also associated severe non-typhoidal Salmonella infections with an increased risk of developing colon cancer.

“A non-typhoid Salmonella infection is often unnoticed by ourselves, but this infection is recognized by our immune system! Our study examined whether these mild, undetected non-typhoid Salmonella infections increase the risk of colon cancer. The idea behind this is that with repeated mild bacterial infections, there is a greater chance that a bacterium will invade and manipulate cells that have already made several steps into cancer development due to a previous infection, said Virginie Stévenin. , postdoctoral researcher at the grandchildren’s workshop.

Search results
To find out if there is an increased risk of colon cancer following exposure to non-typhoid Salmonella, researchers measured the levels of antibodies to non-typhoid Salmonella in more than 100 human blood samples to determine the rate of infections not detected. The researchers found that people who had developed colorectal cancer were also more often exposed to mild Salmonella infections. Salmonella could also be detected in intestinal tumors of mice after infection.

“We also found that more mild infections increased the growth rate of these intestinal cancers. Additionally, in a cell culture model, Salmonella was found to infect cells more rapidly with the potential to become fully transformed cancer cells, promoting further cancer formation”. said LUMC, Professor Jacques (Sjaak) Neefjes.

In short, a risk factor
Jun Sun, a professor at the University of Illinois at Chicago concludes: ‘These experiments suggest that non-typhoidal Salmonella infections may increase colon cancer risk by affecting one step in the multistep process of cancer formation. Avoiding such completely infection is difficult, as no Salmonella typhoid is common in livestock and our food, but exposure to the bacteria can be reduced by good hygiene practices when handling and preparing food.”

read it original article in Cell Reports Medicine.