Clostridium difficile, a bacterium that causes severe diarrhea, can be difficult to treat with antibiotics. Stefan Hyman/University of Leicester hide caption

itoggle caption Stefan Hyman/University of Leicester

Billie Iverson, 86, of Cranston, R.I., recently underwent a transplant of intestinal microbes that likely saved her life. Ryan T. Conaty for NPR hide caption

itoggle caption Ryan T. Conaty for NPR

Microbiologist Emma Allen-Vercoe invented the Robogut, a mechanical device that mimics conditions in the human colon. Courtesy of thestar.com hide caption

itoggle caption Courtesy of thestar.com