Gut Reaction

Scientists discover that repeated food poisoning can trigger chronic disease.

Food poisoning may be the unwanted gift that keeps on giving — at least according to a new study. A startling discovery by UC Santa Barbara scientists, published today in the journal Science, reveals how a past history of bacterial infections adds up with age to cause severe inflammatory disease.

Small bacterial infections, which may go unnoticed and which clear the body without treatment — such as occurs in mild food poisoning — nevertheless can start a chain of events that leads to chronic inflammation and life-threatening colitis. The new findings also may identify the long-mysterious origins of inflammatory bowel disease (IBD).

“We have discovered an environmental and pathogenic origin of chronic intestinal inflammation in the course of modeling human food poisoning as it occurs repeatedly over the adult lifespan,” co-author Marth explained. “Remarkably, salmonellae have figured out a way to disrupt a previously unknown protective mechanism in the gut that normally prevents intestinal inflammation.”

A breakthrough eight years in the making, the multi-institution collaboration was launched to investigate the origin of chronic inflammatory diseases spanning colitis and IBD. The group’s radically different hypothesis took shape from a few possible clues, starting with increasing evidence that the genetic makeup of an individual plays a limited role in common inflammatory diseases, including colitis and IBD. Twins show relatively small concordance for both developing IBD, for example. Such findings implicate unknown environmental factors in disease origins.

Noting that studies from other laboratories had reported seasonal bacterial infections in humans were correlated with increased diagnoses of IBD, the investigators hypothesized that recurrent low-grade bacterial infections may trigger the onset of chronic inflammation.