• Clostridioides difficile is a moderately-sized Gram-positive, endospore-producing bacillus.
• Motile with a peritrichous (def) arrangement of flagella.
• An obligate anaerobe (def).

Habitat

• Colonizes the intestinal tract in a small proportion of healthy humans.

Source

• Transmitted person to person by the fecal-oral route.

Epidemiology

• Colonizes the intestinal tract in less than 5% of healthy humans.
• Endospores are frequently found around the beds and bathrooms of infected individuals.
• Exposure to antibiotics is associated with overgrowth of C difficile in the intestine and development of antibiotic-associated colitis.
• Antibiotic-associated colitis is especially common in older adults. It is thought that C. difficile survives the exposure to the antibiotic by sporulation. After the antibiotic is gone, the endospores germinate and C. difficile overgrows the intestinal tract and secretes toxin A and toxin B that have cytotoxic effects on the cells.

Clinical Disease

• Can range from self-limiting diarrhea to potentially fatal pseudomembranous colitis (def).

C. difficile is a common healthcare-associated infection (HAIs) and is the most frequent cause of health-care-associated diarrhea. C. difficile infection often recurs and can progress to sepsis and death. CDC has estimated that there are about 250,000 C. difficile infections (CDI) in hospitalized patients each year and is linked to 14,000 American deaths each year.

Antibiotic-associated colitis is especially common in older adults. It is thought that C. difficile survives the exposure to the antibiotic by sporulation. After the antibiotic is no longer in the body, the endospores germinate and C. difficile overgrows the intestinal tract and secretes toxin A and toxin B that have a cytotoxic effect on the epithelial cells of the colon. C.difficile has become increasingly resistant to antibiotics in recent years making treatment often difficult. There has been a great deal of success in treating the infection with fecal transplants, still primarily an experimental procedure. Polymerase chain reaction (PCRs) assays, which test for the bacterial gene encoding toxin B, are highly sensitive and specific for the presence of a toxin-producing Clostridium difficile organism. The most successful technique in restricting C. difficile infections has been the restriction of the use of antimicrobial agents.

From Clostridium difficile Colitis, by Craig A Gronczewski, MD, Staff Physician, Department of Emergency Medicine, Medical College of Pennsylvania; and Jonathan P Katz, MD, Instructor, Department of Medicine, University of Pennsylvania School of Medicine.