Date of Award


Document Type


Degree Name

Master of Medical Science (MMSc)

First Advisor

Paul Feuerstadt, MD, FACG, AGAF


Small intestinal bacterial overgrowth is a heterogenous disease characterized by dysbiosis of the small bowel microbiome. The standard of care for small intestinal bacterial overgrowth is antimicrobial therapy with rifaximin, but there are high rates of recurrence. Fecal microbiota transplantation is effective as an adjunct to antimicrobial therapy in repairing recurring dysbiosis seen with Clostridioides difficile infection. However, no studies have investigated adjunct fecal microbiota transplant for small intestinal bacterial overgrowth. We propose a prospective placebo-controlled randomized clinical trial to examine whether adjunct fecal microbiota transplantation following rifaximin decontamination can reduce the recurrence of small intestinal bacterial overgrowth. Subjects with suspected small intestinal bacterial overgrowth will be randomized to receive rifaximin therapy followed by oral capsule fecal microbiota transplant or standard rifaximin followed by a placebo. Findings may be used to inform small intestinal bacterial overgrowth medical therapy and justify future research considering fecal microbiota transplantation.