Antibiotics
The last area of research which indicates that gut bacteria play a part in IBS stems from the SIBO theory and the successful use of certain antibiotics as a treatment for IBS. Two particular antibiotics are used, Rifaximin and Neomycin, with Rifaximin showing a slight edge in terms of effectiveness. These antibiotics have been chosen because they are not absorbed in the stomach, and therefore are thought to be able to attack any bacteria lurking within the small intestine. Studies have shown that these antibiotics result in significant symptom improvement and may also be associated with positive changes in the hydrogen breath test. The downsides to the use of antibiotics have to do with their high cost as well as concern that they contribute to the development of more resistant forms of bacteria. Antibiotics would only be prescribed to individuals in which the hydrogen breath test indicates the presence of bacterial overgrowth in the small intestine.
Sources:
Drossman, D. “Treatment for Bacterial Overgrowth in the Irritable Bowel Syndrome” Annals of Internal Medicine 2006 145:626-628.
Fumi, A. & Trexler, K. “ Rifaximin Treatment for Symptoms of Irritable Bowel Syndrome” The Annals of Pharmacotherapy 2008 42:408-412.
Garcia Rodriguez, L. & Ruigomez, A. “ Increased risk of irritable bowel syndrome after bacterial gastroenteritis: cohort study” BMJ 1999 318:565-566.
Gwee, K., Collins, S., Read, N., Rajnakova, A., Deng, Y., Graham, J., McKendrick, M. & Moochala, S. “Increased rectal mucosal expression of interleukin 1ß in recently acquired post-infectious irritable bowel syndrome Gut 2003 52:523-526.
Lin, H. “
Small Intestinal Bacterial Overgrowth” Journal of the American Medical Association 2004 292:852-858.
O’Mahony, L., McCarthy, J., Kelly, P., Hurley, G., Luo, F., Chen, K., O’Sullivan, G., Kiely, B., Collins, J., Shanahan, F. & Quigley, E. “ Lactobacillus and bifidobacterium in irritable bowel syndrome: Symptom responses and relationship to cytokine profiles” Gastroenterology 2005 128:541-551.
Pimental, M., Park, S., Mirocha, J., Kane, S., & Kong, Y. “The Effect of a Nonabsorbed Oral Antibiotic (Rifaximin) on the Symptoms of the Irritable Bowel Syndrome” Annals of Internal Medicine (2006) 145:557-563.
Sharara, A. Aoun, A., Abdul-Baki, H., Mounzer, R., Sidani, S. & ElHaii “ A Randomized Double-Blind Placebo-Controlled Trial of Rifaximin in Patients with Abdominal Bloating and Flatulence” American Journal of Gastroenterology (2006) 101:326.
Spiller, R. “Postinfectious irritable bowel syndrome” Gastroenterology 2003 124:1662-1671.
