Clostridium perfringens is an anaerobic Gram-positive bacillus that produces spores in the human gut. It is found as a part the normal flora of the intestinal tracts of both animals and humans, as well as being found on soil, clothing, and on the skin of the lower legs of humans. It is capable of growing at temperatures of 44°C to 49°C (111.2°F to 120°F) with a doubling time of twelve minutes. In effect, at this ideal temperature, a single bacterium can produce over one million offspring in just four hours. Even though it is less hazardous than its cousins, it is still the third most deadly toxin known to man. Rarely, a ß-strain of C. perfringens is formed from improperly cooled foods, making it very toxic, and thus fatal.
In the late 1980’s, the University of Baghdad developed a genetically engineered smallpox virus which had been integrated with the epsilon-toxin of C. perfringens producing a chimera, or monster virus – aka a “doomsday bug”. The epsilon-toxin had been planted inside the smallpox DNA to speed up the processes of infection and death, making the virus more virulent and a ferociously dangerous weapon for a biological attack.
C. perfringens is most frequently responsible for released toxins and enzymes that cause tissue damage. These conditions are known as anaerobic cellulitis, myonecrosis, or gas gangrene. Other clostridia that are occasionally responsible include C. novyi and C. septicum, and others on very rare occasions.
Gas gangrene nearly always starts in a wound, usually in a limb, with an anaerobic, or dead tissue, area. This may be muscle or other tissue damaged at the time of the injury, or a large blood clot. Next, this susceptible area must be contaminated with clostridial spores. Then, if the oxygen tension is low enough, the spores will germinate, revert to their vegetative state, and begin to multiply. When clostridia are established in a wound, their enzymes and toxins begin to spread outwards, killing more tissue. This enlarges the anaerobic area into which the clostridia can spread. Gas is produced by bacterial enzymes as they attack the tissues, adding to the pathology as it splits muscles apart to allow the infection to extend. It also inflates bundles of muscles inside their relatively rigid fascial sheaths. When the pressure of the gas rises above the arterial pressure, the blood supply to the bundle is cut off and the whole of it becomes dead tissue. This happens more easily because the blood pressure is likely to be low as a result of the original injury, and it is reduced still further as the absorption of toxins leads to septic shock. When these factors combine, gangrene can spread to a whole limb in a matter of hours, and death soon follows. Another disturbing factor is, when touched, the offending area will sound like the crinkle of cellophane.
Gas gangrene can develop in the uterus after mechanically induced abortion, and is seen more frequently after an illegal abortion. Rapidly developing gas gangrene can also develop in any section of the bowel that is deprived of a normal blood flow. Gas gangrene can also complicate amputations performed for diabetic or arteriosclerotic gangrene. These conditions are usually treated with surgical removal of the offending area, as well as with penicillin or other antibiotics and antitoxins. Hyperbaric chambers have been used with limited success.
Prevention involves early thorough cleaning of dirty wounds, with the removal of all dead or devitalized tissue. Where an injury has caused considerable tissue destruction, the wound should not be totally sutured immediately, but left open for a time. This is to reduce the possibility of a development of an anaerobic area in a closed wound in which tissues may continue to swell as inflammation develops. The rule applies to severe compound fractures or crush, missile, or blast injuries as those usually found during wartime. Some surgeons accustomed to peacetime surgery forget the need for delaying the initial suturing when faced with battle casualties for the first time, and unnecessary cases of gas gangrene begin to appear.
In addition to gas gangrene, C. perfringens is a common cause of food poisoning, usually associated with contaminated meat dishes. Spores that survive the normal cooking process, germinate as meat cools, and, within a few hours sitting at room temperature, massive numbers of the bacteria have developed. After ingestion, the bacteria continue their growth in the intestines where toxins are released. These toxins cause diarrhea, cramps, and abdominal pain. Onset is eight to twenty hours after ingestion. Symptoms only last for a day or so, and death rarely occurs. In New Guinea,C. perfringens (type C) is responsible for a unique type of gastroenteritis referred to as pigbel, so named because it is often the result of eating contaminated pork. Mortality rates are high, especially in children.