Irritable bowel common after bacterial dysentery

NEW YORK (Reuters Health) - A Canadian study shows that a bout of bacterial dysentery greatly increases the chances of developing irritable bowel syndrome (IBS), which is characterized by abdominal pain, bloating, diarrhea, and constipation.

This study, lead investigator Dr. John K. Marshall told Reuters Health, "demonstrate conclusively" that postinfectious IBS is a "real and significant clinical phenomenon."

In the journal Gastroenterology, Marshall of McMaster University Medical Center, Hamilton and colleagues report their study more than 2000 residents of Walkerton, a small rural town in Ontario, who had been exposed to contaminated municipal water some two years earlier.

This led to an outbreak of the potentially deadly strain of E. coli known as O157:H7, which is typically contracted through contaminated food or water and can cause bloody diarrhea, vomiting and cramps.

Exposure to the contaminated town water also led to an outbreak of gastroenteritis caused by Campylobacter jejuni, a major cause of traveler's diarrhea.

In all, about 700 subjects did not develop gastroenteritis at the time of the outbreak and were designated as controls. Of this control group, 10.1 percent developed IBS, compared to 27.5 percent of subjects with self-reported gastritis and 36.2 percent of those with clinically suspected gastroenteritis.

Thus, say the investigators, the relative risk of developing IBS was 4.8-fold higher in residents who had experienced bacterial gastroenteritis from contamination.

Risk factors for postinfectious IBS included being female, being younger and having weight loss and prolonged diarrhea.

"While many residents of Walkerton have recovered fully," Marshall observed, "others continue to suffer."

He concluded: "If we can identify patients at risk of postinfectious IBS at the time of enteric infection, we hope one day to be able to target them for early treatment and improve their outcomes."

SOURCE: Gastroenterology September 2006.