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Salmonella infection chance of developing colon cancer three times higher

Salmonella infection chance of developing colon cancer three times higher

January 17, 2018

New research from Leiden University Medical Center and the National Public Health and the Environment in The Netherlands. This epidemiological study examined whether severe Salmonella infection, usually acquired from contaminated food, is associated with increased colon cancer risk in humans.

Their findings were recently published in the scientific journal PLOS ONE. “Just by comparison: eating red meat gives a 1.2 times higher risk of developing colon cancer,” says Sjaak Neefjes. He is Professor of Chemical Immunology at the LUMC. It is a contamination with Salmonella enteritidis, a bacterium that occurs on chicken products and raw eggs. “If you heat your food well, there is nothing wrong.”

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National research

Neefjes has been examining whether salmonella bacteria increase the risk of cancer. He previously showed how salmonella converts healthy cells into cancer cells and has repeated this in experimental animals. Here he saw how they got bowel cancer after a large salmonella infection. That was the reason for him to start a new, national survey.

The study looked at the data of about 160,000 colorectal cancer patients, of whom approximately 30,000 people had previously contracted food poisoning due to salmonella infection. “Those people are seriously ill because of such an infection, go to the GP or medical specialist and then receive the diagnosis” Salmonella “. The RIVM keeps track of how many Dutch people get sick by this bacterium, “Neefjes explains. With the help of the Central Bureau for Statistics, these data are linked to the database of the Dutch Cancer Registry, which records how often different forms of cancer occur in the Netherlands.

Earlier Research

What turned out? A diagnosed infection with Salmonella enteritidis makes the chance of someone getting colon cancer up to three times greater. “This is an important discovery with many consequences, but must be used carefully. After all, it is always possible that there is another reason for this connection, although we did not find it, “says Neefjes. That is why he and his colleagues are conducting the same kind of research abroad to confirm the Dutch findings. The outcome of this is important for the Health Council, the advisory body that determines who is eligible for screening for colorectal cancer.

Methods and results

We performed a nationwide registry-based study to assess colon cancer risk after diagnosed Salmonella infection. National infectious disease surveillance records (1999–2015) for Dutch residents aged ≥20 years when diagnosed with salmonellosis (n = 14,264) were linked to the Netherlands Cancer Registry. Salmonella-infected patients were laboratory-confirmed under medical consultation after 1–2 weeks of illness. These datasets also contained information on Salmonella serovar and type of infection. Colon cancer risk (overall and per colon subsite) among patients with a diagnosed Salmonella infection was compared with expected colon cancer risk in the general population.

Data from the nationwide registry of histo- and cytopathology (PALGA) and Statistics Netherlands (CBS) allowed assessing potential effects of age, gender, latency, socioeconomic status, genetic predisposition, inflammatory bowel disease (IBD), and tumor features. We found that compared to the general population, colon cancer risk was significantly increased (standardized incidence ratio [SIR] 1.54; 95%CI 1.09–2.10) among patients with Salmonella infection diagnosed <60 years of age. Such increased risk concerned specifically the ascending/transverse colon (SIR 2.12; 95%CI 1.38–3.09) after S. Enteritidis infection (SIR 2.97; 95%CI 1.73–4.76). Salmonellosis occurred more frequently among colon cancer patients with pre-infectious IBD, a known risk factor for colon cancer. Colon tumors of patients with a history of Salmonella infection were mostly of low grade.


Patients diagnosed with severe salmonellosis have an increased risk of developing cancer in the ascending/transverse parts of the colon. This risk concerns particularly S. Enteritidis infection, suggesting a contribution of this major foodborne pathogen to colon cancer.

Article as published by PLOS journal.
Lapo Mughini-Gras, Michael Schaapveld, Jolanda Kramers, Sofie Mooi, E. Andra Neefjes-Borst, Wilfrid van Pelt, Jacques Neefjes



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Posted : 2018 , News