Gut bacteria linked to cancer

A study, to be published in the Journal of Medical Microbiology, by Mark Huycke of the Department of Veterans Affairs Medical Center, Oklahoma City, suggests that a common gut bacterium Enterococcus faecalis releases a compound that damages DNA.

We have uncountable numbers of bacteria in our guts - as normal commensals. E. faecalis uses two type of metabolism, fermentation and respiration to survive in the gut. It is the fermentation that releases a super oxide - that may damage DNA.
Huycke and colleagues found that signals from E. faecalis affected the activity of 42 genes that are involved in the regulation of the lifecycle and death of the epithelial cells that line the gut.

They suspect E. faecalis may have developed new ways of triggering colon cells to become cancerous, which happens when the bacterium is in fermentation mode and rapidly affects the lining of the colon.

Cancer in the gut almost always starts in the colon where billions of bacteria are in contact with the cells of the lining. The bacterial communities are extremely complex, making it very difficult to study their interaction with tissue cells. This study is one of the first to unravel such a relationship.

Other experts suggest E.faecalis may not be the only candidate for triggering colon cancer.