C. diff. is a bacterium that infects the large intestine, causing difficult GI symptoms like frequent diarrhea. C. diff. is a widespread infection among patients who have been hospitalized, estimated at almost a half-million cases per year. It’s extremely contagious.
C. diff. has been known to lead to dangerous problems like sepsis if left untreated. Previous research has found there is a higher amount of C. diff. in cancerous lesions than in healthy body tissue, but a recent study published in Cancer Discovery by Johns Hopkins and Vanderbilt University has expanded upon the link between C. diff. and colon cancer. This study, which was conducted in mice, found that C. diff. bacteria may change normal cells to cancer cells.
In colon cancer, the surface of the colon tends to be covered in biofilms – or dense amounts of bacteria. In this study, researchers found that C. diff. was capable of producing colorectal tumors in a cascade.
“Big picture, we’re working to learn what the exact mechanism for this is,” said Julia L. Drewes, PhD, assistant professor of medicine at Johns Hopkins University, Baltimore, and a coauthor of the study.
Anyone can get C. diff., but certain people are more susceptible.
“People who are over 65, have weakened immune systems, live in nursing homes, or work in health care settings are most at risk for C. diff.,” said Lilian Chen, MD, a colon and rectal surgeon at Tufts Medical Centerand assistant professor of surgery at Tufts University, both in Boston. “People with C. diff. can also get it again. One in six patients will end up with recurrent infections.”
Another risk factor: taking antibiotics. “Trillions of microbes are normally found in and on our body, including both good and bad bacteria,” said Caroline Um, PhD, MPH, principal scientist in epidemiology research for the American Cancer Society. “Normally, good bacteria help us fight against bad bacteria such as C. diff. However, you may have a greater chance of C. diff. infection after taking antibiotics, since they usually wipe out both good and bad bacteria in our gut.”
C. diff. is transmitted through stool, often if someone doesn’t wash their hands after using the bathroom. If you touch that person’s skin or a surface that person touched, your body can be “colonized” with the bacteria.
“Once someone is colonized with C. diff., you find it everywhere in their environment. In fact, C. diff. is all around all of us,” said Aasma Shaukat, MD, MPH, a gastroenterologist at the NYU Langone Medical Center and director of GI outcomes research at New York University. “In a healthy person, this kind of exposure doesn’t matter because C. diff. will not make them sick. It’s when someone has a compromised immune system that C. diff. becomes a concern.”
C. diff. may kickstart the process of how cancer begins to form through inflammation
“There are two types of toxins present in C. diff.: toxin A and toxin B,” said Dr. Drewes. “We need to do more work in order to determine an exact mechanism, but toxin B, or TcdB, which is found in a majority of C. diff. infections, appears to drive inflammation in the body. This inflammation contributes to cell damage in the colon, which may then be connected to a mutation that can cause cancer.”
The findings could help researchers understand why so many people under the age of 50 are now being diagnosed with colon cancer.
“We need a better understanding of the potential role of C. diff. in colorectal cancer before we can determine whether this changes current colorectal cancer screening guidelines,” said Dr. Um. “However, it’s a good idea to talk with your health care professional about colorectal cancer screening, regardless of whether you have had C. diff.. Various factors like smoking, poor diet, being overweight, or having a family history of colorectal cancer can affect an individual’s risk.”
A version of this article first appeared on WebMD.com.
