Small Intestinal Bacterial Overgrowth (cont.)
Bhupinder Anand, MD
In this Article
How is small intestinal bacterial overgrowth treated?
SIBO has been recognized for many years as a problem with severe disorders of intestinal muscles and intestinal obstruction. The treatment has been antibiotics, and they are very effective. The difficulty is that the disease causing the SIBO often cannot be corrected. As a result, symptoms frequently return when the antibiotics are stopped, and it may be necessary to treat the patient with antibiotics repeatedly or even continuously.
SIBO associated with IBS
There are very few rigorous, scientific studies on the treatment of irritable bowel syndrome with therapies that are directed specifically to the possibility of underlying SIBO. That has not stopped physicians from trying unproven treatments. The discussion of treatment that follows is based on the minimal scientific evidence that is available (two trials) as well as the anecdotal (observed but not scientifically demonstrated) experience of physicians who see patients with irritable bowel syndrome.
The two most common treatments for SIBO in patients with IBS are oral antibiotics and probiotics. Probiotics are live bacteria that, when ingested by an individual, result in a health benefit. The most common probiotic bacteria are lactobacilli (also used in the production of yogurt) and bifidobacteria. Both of these bacteria are found in the intestine of normal individuals. There are numerous explanations for how probiotic bacteria might benefit individuals. However, the beneficial action has not been identified clearly. It may be that the probiotic bacteria inhibit other bacteria in the intestine that may be causing symptoms, or it may be that the probiotic bacteria act on the host's intestinal immune system to suppress inflammation.
Several antibiotics either alone or in combination have been reported in scientific studies to be successful in treating IBS. Treatment success, when measured by either symptom improvement or by the normalization of the hydrogen breath test, ranges from 40% to 70%. When one antibiotic fails, the doctor may add another antibiotic or change to a different antibiotic. However, the doses of antibiotics, the duration of treatment, and the need for maintenance therapy to prevent recurrence of SIBO have not been adequately studied. Most physicians use standard doses of antibiotics for one to two weeks. Probiotics may be used alone, in combination with antibiotics, or for prolonged maintenance. When probiotics are used, it probably is best to use one of the several probiotics that have been studied in medical trials and shown to have an effect on the small intestine, though not necessarily in SIBO. The commonly sold probiotics in health-food stores may not be effective. Moreover, they often do not contain the bacteria stated on the labels or the bacteria are dead. The following are some treatment options:
Treatment with antibiotics versus probiotics
It is the author's personal belief that for short-term (1-2 weeks) treatment, antibiotics are more effective than probiotics. However, antibiotics do have certain disadvantages. Specifically, symptoms tend to recur after treatment is discontinued, and prolonged or repeated courses of treatment may be necessary in some patients. Physicians are reluctant to prescribe prolonged or repeated courses of antibiotics because of concern over long-term side effects of the antibiotics and the emergence of bacteria that are resistant to the antibiotics. Physicians have less concern over long-term side effects or the emergence of resistant bacteria with probiotics and, therefore, are more willing to prescribe probiotics repeatedly and for prolonged periods. One option is to initially treat the patient with a short course of antibiotics and then long-term with probiotics. Long-term studies comparing antibiotics, probiotics, and combinations of antibiotics and probiotics are badly needed.
Medically Reviewed by a Doctor on 3/10/2014
Viewers share their comments
Small Intestinal Bacterial Overgrowth - Symptoms Question: Please describe the symptoms and treatment of your small intestinal bacterial overgrowth.
Small Intestinal Bacterial Overgrowth - Causes Question: What was the cause of your intestinal bacterial overgrowth?
Small Intestinal Bacterial Overgrowth - Experience Question: Please describe your experience with small intestinal bacterial overgrowth (SIBO).