Merck Manual

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Overview of Clostridial Infections


Larry M. Bush

, MD, FACP, Charles E. Schmidt College of Medicine, Florida Atlantic University;

Maria T. Vazquez-Pertejo

, MD, FACP, Wellington Regional Medical Center

Reviewed/Revised Jun 2023
Topic Resources

Clostridia are spore-forming, gram-positive, anaerobic bacilli present widely in dust, soil, and vegetation and as normal flora in mammalian gastrointestinal tracts. Pathogenic species produce tissue-destructive and neural exotoxins that contribute to disease manifestations.

Nearly 100 Clostridium species have been identified, but only 25 to 30 commonly cause human or animal disease.

Pathophysiology of Clostridial Infections

The pathogenic species produce tissue-destructive and neural exotoxins that are responsible for disease manifestations. Clostridia may become pathogenic when tissue oxygen tension and pH are low. Such an anaerobic environment may develop in ischemic or devitalized tissue, as occurs in primary arterial insufficiency or after severe penetrating or crushing injuries. The deeper and more severe the wound, the more prone the patient is to clostridial infection, especially if there is even minimal contamination by foreign matter.

Clostridial disease can also occur after injection of illicit drugs.

Serious noninfectious disease can occur after ingestion of home-canned foods in which clostridia have produced toxins.

Diseases Caused by Clostridia

Diseases caused by clostridia (see table ) include


The most frequent clostridial infection is minor, self-limited gastroenteritis, typically due to C. perfringens type A. Serious clostridial diseases are relatively rare but can be fatal.

Abdominal disorders, such as cholecystitis, peritonitis, ruptured appendix, and bowel perforation can involve C. perfringens, C. ramosum, and many others.

Muscle necrosis and soft-tissue infection, which is characterized by crepitant cellulitis, myositis, and clostridial myonecrosis, can be caused by C. perfringens.

Skin and tissue necrosis can be caused by bloodborne C. septicum from the colon.

Clostridia also appear as components of mixed flora in common mild wound infections; their role in such infections is unclear.

Hospital-acquired clostridial infection is increasing, particularly in postoperative and immunocompromised patients. Severe clostridial sepsis may complicate intestinal perforation and obstruction.

NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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