Clostridium perfringens causes two distinct diseases, gas gangrene and food poisoning, depending on the route of entry into the body.

Disease: Gas Gangrene

Gas gangrene (myonecrosis, necrotizing fasciitis) is one of the two diseases caused by C. perfringens (Figure 1). Gas gangrene is also caused by other histotoxic clostridia such as Clostridium histolyticum, Clostridium septicum, Clostridium novyi, and Clostridium sordellii. (C. sordellii also causes toxic shock syndrome in postpartum and postabortion women.)

Fig 1 Gas gangrene. Note large area of necrosis on lateral aspect of foot. Necrosis is mainly caused by lecithinase produced by Clostridium perfringens. Gas in tissue is a feature of gangrene produced by these anaerobic bacteria. A large gas- and fluid-filled bulla is seen near the ankle. (Used with permission from David Kaplan, MD)

Transmission

Spores are located in the soil; vegetative cells are members of the normal flora of the colon and vagina. Gas gangrene is associated with war wounds, automobile and accidents, and septic abortions (endometritis).

Pathogenesis

Organisms grow in traumatized tissue (especially muscle) and produce a variety of toxins. The most important is alpha toxin (lecithinase), which damages cell membranes, including those of erythrocytes, resulting in hemolysis. Degradative enzymes produce gas in tissues.

Clinical Findings

Pain, edema, cellulitis, and gangrene (necrosis) occur in the wound area (see Figure 1). If crepitus is palpated in the affected tissue, it indicates gas in the tissue. This gas is typically hydrogen produced by the anaerobic bacteria. Hemolysis and jaundice are common, as are blood-tinged exudates. Shock and death can ensue. Mortality rates are high.

Laboratory Diagnosis

Smears of tissue and exudate samples show large gram- positive rods. Spores are not usually seen because they are formed primarily under nutritionally deficient conditions. The organisms are cultured anaerobically and then identified by sugar fermentation reactions and organic acid production. Clostridium perfringens colonies exhibit a double zone of hemolysis on blood agar. The colonies also produce a precipitate in egg yolk agar caused by the action of its lectthinase. Serologic tests are not useful.

Treatment

Penicillin G is the antibiotic of choice. Wounds should be debrided.

Prevention

Wounds should be cleansed and debrided. Penicillin may be given for prophylaxis. There is no vaccine.

Disease: Food Poisoning

Food poisoning is the second disease caused by C.perfringens.

Transmission

Spores are located in soil and can contaminate food. The heat-resistant spores survive cooking and germinate. The organisms grow to large numbers in reheated foods, especially meat dishes.

Pathogenesis

Clostridium perfringens is a member of the normal flora in the colon but not in the small bowel, where the enterotoxin acts to cause diarrhea. The mode of action of the entero- toxin is the same as that of the enterotoxin of Staphylococcus aureus (ie., it acts as a superantigen).

Clinical Findings

The disease has an 8- to 16-hour incubation period and is characterized by watery diarrhea with cramps and little vomiting. It resolves in 24 hours.

Laboratory Diagnosis

This is not usually done. There is no assay for the toxin. Large numbers of the organisms can be isolated from food.

Treatment

Symptomatic treatment is given ; no antimicrobial drugs are administered .

Prevention

There are no specific preventive measures. Food should be adequately cooked to kill the organism.