A case of small intestinal bacterial overgrowth in a healthy female patient caused by long-term oral proton pump inhibitor administration

Small-intestinal bacterial overgrowth (SIBO) causes gastrointestinal symptoms. Proton pump inhibitors (PPIs) are commonly used for acid peptic diseases; however, their long-term use can alter the gut microbiota, resulting in adverse effects. We herein report the case of a 26-year-old Japanese woman with SIBO caused by prolonged PPI use. After switching to a H2 receptor antagonist, her symptoms and blood test results improved. This case highlights the need to understand the pathogenesis of SIBO and also the risks associated with prolonged PPI use.