Evaluating a bacterial hypothesis in IBS using a modification of Koch's postulates: part 1.

It has recently been suggested that irritable bowel syndrome (IBS) symptoms are due partly to small intestinal bacterial overgrowth (SIBO). This "SIBO hypothesis" has led to the use of antibiotics to treat IBS. Koch's postulates have long been used to establish bacteria as a cause of diseases such as tuberculosis. Because SIBO is not a single organism, we use modified Koch's postulates to argue for antibiotics and an SIBO hypothesis in the pathophysiology of IBS. We show that there is evidence for SIBO, that it is culturable, that antibiotic elimination of the bacteria improves subjects clinically, and that when the bacteria return, the symptoms return. On the basis of proof of a bacterial cause of IBS, antibiotics may be a good choice of therapy.