Clostridium difficile (pronunciation below) (from the Greek kloster 'spindle', and Latin difficile, 'difficult, obstinate'), also known as CDF/cdf, or C. diff, is a species of Gram-positive spore-forming bacteria that is best known for causing antibiotic-associated diarrhea (AAD). While it can be a minor normal component of colonic flora, the bacterium is thought to cause disease when competing bacteria in the gut have been wiped out by antibiotic treatments. difficile infections are the most common cause of pseudomembranous colitis, and in rare cases this can progress to toxic mega colon, which can be life-threatening.
Difficile infection is a growing problem in healthcare facilities. Outbreaks occur when humans accidentally ingest spores in a medical facility. The infection kills 14,000 people a year in America alone. When the bacteria are in a colon in which normal gut flora has been destroyed (usually after a broad-spectrum antibiotic such as clindamycin has been used), the gut becomes overrun with C. difficile. The bacteria release toxins that can cause bloating and diarrhea, with abdominal pain, which may become severe.