Can Healthy Bacteria Quiet An Angry Bowel? by Dr. James Pilla

Mrs. B presents for an office visit with a 15 year history of diarrhea, abdominal pain, bloating and excessive gas. She is 41 years old and quite frustrated with these nagging symptoms. She has undergone both upper and lower "scope tests" (EGD and colonoscopy), extensive blood work, and X-rays all of which were normal. She has tried multiple IBS (irritable bowel syndrome) medications including antispasmodics, fiber, antidepressants, and antidiarrheals, none of which relieved her symptoms. She recently read an article on the web about a relationship between IBS and small intestinal bacterial overgrowth(SIBO). She wonders if trying an antibiotic would be helpful and asks for advice.

What is Irritable Bowel Syndrome?
IBS or irritable bowel syndrome is a chronic gastrointestinal condition characterized by symptoms of diarrhea or constipation(or both), abdominal pain and bloating. It is one of the most frequently diagnosed disorders in primary care and gastroenterology practices with approximately 3%-20% of the US population affected.

How Do You Know If You Have IBS?
Unfortunately there are no simple blood tests or scope tests to accurately diagnose IBS. Diagnosis is primarily based on symptoms. International experts met in Rome to come up with the Rome III criteria. (Funny how they didn't meet in Scranton for this meeting.) These criteria are based on symptoms of abdominal pain, change in bowel frequency or form and how often symptoms are experienced. Importantly, other conditions that have similar symptoms as IBS such as celiac sprue and microscopic colitis ( see previous newsletters) need to be ruled out with appropriate testing.

How Is IBS Treated?
Current treatment depends on an individual's predominant symptoms. Available therapies include bulking agents such as psyllium, laxatives, antidiarrheals, antispasmodics, and antidepressants. Although effective therapies for IBS are limited, the outlook is promising.

Bacteria Outnumber Our Cells
When we think of bacteria, or "germs," we usually think of infection and disease. The truth is that not all bacteria are bad guys and many can be considered "friendly." That is good news since, by sheer numbers alone, bacterial cells in the body outnumber our own by a factor of 10, with 50 trillion bacteria living in the colon, or large intestine, alone. Fortunately, bacterial cells are much smaller than human cells - so by weight the average adult only carries about 2 pounds of bacteria. These bacteria are ancient having evolved within us since the very beginnings of man. They have been largely unstudied until the last decade as scientists have just begun to chart the complex relationship between the tiny bugs in our gut and our health.

What About All The Hype For Antibiotics In Treating IBS?
Recently, the role of gut bacteria in IBS has been looked into by some investigators with the suggestion that some IBS patients may harbor small intestinal bacterial overgrowth, or SIBO . SIBO occurs when bacteria grow excessively in the small intestine, an area in the GI tract that usually doesn't have any or just small numbers of bacteria. SIBO has been associated with diarrhea, bloating, poor absorption of nutrients, low blood count, and weight loss. Current studies suggest that treatment with antibiotics such as Rifaximin or with probiotics("good bacteria" see previous newsletter) may relieve some symptoms of IBS especially abdominal bloating.

The Dilemma:

• Symptoms of IBS and SIBO are similar so it is difficult to say that SIBO is present in individual irritable bowel patients

• Testing such as the Lactulose Hydrogen Breath Test to confirm SIBO is currently not perfect and therefore can sometimes be inaccurate

• If antibiotics are tried , how long and what is the best to use? Do the "bad bacteria" just come back after antibiotics are stopped? We don't have the answers to these questions yet.

• Are there any risks to treating with antibiotics? Risk of potential side effects and risk of developing antibiotic-associated infection( i.e. Clostridium difficile, see previous newsletter) One potential advantage of the antibiotic Rifaximin is that it works only in the gut and not systemically making side effects less likely.

Current Recommendations
The jury is still out on whether SIBO affects IBS and whether antibiotics are helpful. The role of bacteria in IBS and the future role of antibiotics or probiotics is promising, but currently the evidence for effective treatment of IBS with antibiotics is not entirely convincing. Further studies are needed and until then the decision to test and treat is individualized for each patient.