Culture of Clostridium difficile, an anaerobic bacterium. This bacterium is in some cases able to cause severe diarrhoea leading to pseudomembranous colitis and death. Clostridium difficile has caused many nosocomial outbreaks in hospitals. Viable spores of the bacterium can survive months or years on surfaces. This culture is NAP1 or CD027, an epidemic subtype of toxigenic Clostridium difficile.