General Information: Clostridium difficile R20291 was isolated in Stoke Mandeville Hospital, UK in 2006 and is closely related to the North American hypervirulent BI strains. Clostridium difficile, a Gram-positive, spore-forming anaerobic bacterium, is the leading cause of infectious diarrhea among patients in hospitals worldwide, causing C. difficile infection (CDI). An important nosocomial pathogen, it is frequently associated with antibiotic treatment and causes diseases ranging from antibiotic-associated diarrhea to life-threatening pseudomembraneous colitis.