Study links intestinal bacteria to irritable bowel syndrome

"This is really exciting because it points to the cause of the disease. Treatments for irritable bowel syndrome (IBS) to this point have been directed at symptoms, not any cause," said Dr Mark Pimentel, who is also assistant director of the gastrointestinal motility program at Cedars-Sinai Medical Center in Beverly Hills, Calif.

Symptoms of IBS, which is diagnosed in twice as many women as men, include gas, bloating, abdominal pain, constipation, diarrhea or both.

"We found that 78 per cent of IBS patients have bacterialover growth in the small intestine. Antibiotics got rid of the disease in half of the patients that got rid of the overgrowth," Pimentel said.

Treatments for the gastrointestinal condition currently range from anti-depressants, which are supposed to alter nerve endings in the abdomen, to advice to eat more fibre in order to alleviate constipation.

Last month, the IBS drug Lotronex was pulled from the market by its maker Glaxo Wellcome Plc after the U S Food and Drug Administration (FDA) voiced concerns about side effects and said three deaths might have been related to the product.

Lotronex, marketed as a treatment for women with diarrhea-predominant IBS, was linked to reports of a bowel condition called ischemic colitis, which restricts blood flow to the colon. Some Lotronex users also reported severe complications from constipation.

Zelmac, an experimental drug described as a treatment for women with constipation symptoms of IBS, is expected to be approved by the FDA and launched by its maker Novartis AG. By the middle of next year.

But Pimentel said pharmaceutical companies may want to redirect their research efforts in IBS to target alternatives for eradicating bacteria in the small intestine.

"Once they see this trial, they will really wonder what they’re doing," Pimentel said.

Cedars-Sinai investigators evaluated 202 patients who underwent a specialized breath test to determine the presence of small intestinal bacterial overgrowth, a condition in which bacteria typically found in the colon makes its way up into the small intestine.

The Cedars-Sinai team, which published its study results in the December issue of The American Journal of Gastroenterology, is currently conducting a double-blind study comparing treatment with antibiotics to placebo in IBS patients.