Clostridium perfringens

Definitions & Key takeaways

Clostridium perfringens is a spore-forming, gram-positive obligate anaerobe bacterium that can cause food poisoning. The most common symptoms of Clostridium perfringens food poisoning are abdominal cramps and diarrhea, and vomiting. Clostridium perfringens also causes myonecrosis or gas gangrene once it gets into a wound. It can be deadly unless urgent surgical debridement and antibiotic therapy are initiated rapidly.

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Clostridium perfringens is from the family of Clostridia, and as a family, they’re obligate anaerobes, meaning they don’t require oxygen to thrive, in fact, they’re better off without it.
Anaerobes, clostridia included, tend to lack the enzymes catalase or superoxide dismutase, so oxygen is actually toxic to them.
In nature, they thrive in deep, compact soil, and when they feel the stress of fresh oxygenated air, they often produce spores, which are extremely resilient to the environment, and can even survive cooking.
When conditions improve, for example, when food is slowly cooled or stored, the spores can sprout into full-fledged Clostridia.
In fact, at an optimum temperature, Clostridium perfringens has one of the fastest growing rates of any bacterium! In the lab, when doing a gram stain, Clostridium perfringens is Gram-positive, or purple when Gram stained, and look like big cylinders or rods, also called bacilli.
Clostridium perfringens is a common cause of food poisoning, in fact, it’s sometimes called “the cafeteria germ”. That’s because it typically infects food that’s prepared in large quantities, and then kept warm for prolonged periods, such as in cafeterias or buffets.
Clostridium perfringens are found in the environment and they can accidentally contaminate food when it’s been left out for a while.
If a person eats food contaminated with C. perfringens, the bacteria will soon colonize the gut.
Within 24 hours, the bacteria starts to make clostridium perfringens enterotoxin, or CPE. The CPE specifically targets the tight junctions that connect epithelial cells lining the intestines to one another.
When the tight junctions get destroyed, it causes inflammation and compromises the structural integrity of the intestinal wall.
Fortunately, CPE is heat labile, so prolonged cooking at 72°C or above will inactivate it. And that’s one reason why freshly cooked food is best to eat - the other reason is that it’s simply tastier that way!
But uncooked food - like salads, or reheated food - like leftovers, can be a good home to Clostridium perfringens. The symptoms of Clostridium perfringens enteritis include abdominal cramping, watery diarrhea, and vomiting.
Fortunately, most of these improve over the course of a day, as the bacteria makes its way through the intestines. In terms of treatment, antibiotics aren’t needed, and instead the goal is to keep the individual well hydrated.
Now, instead of getting into food, Clostridium perfringens can also sometimes get into a wound. This can happen when wounds are made by dirty, sharp objects, that come into contact with soil that’s rich with Clostridium perfringens and other anaerobes, like gardening or farming equipment.
And if there’s a deep wound, it can cause clostridial myonecrosis. That’s where another toxin, Clostridium perfringens alpha toxin, or CPAT, causes direct damage to cells, causing them to swell up and lyse - or pop.
The result is rapid, massive destruction of muscular and soft tissues, eventually resulting in tissue death or gangrene.
Symptoms of myonecrosis are extreme pain and swelling, and sometimes thin, watery pus can leak out of the wound. Occasionally, there’s so much tissue damage that blood vessels break and create blood filled bullae on the skin above gangrenous tissue.
A classic sign is crepitus - which is the sound of crackles as you press down around the wound. It feels like gas moving around in the tissue, which is why myonecrosis is sometimes called gas gangrene.
The fast-moving infection and massive tissue destruction can lead to fever and tachycardia, and can even progress to hypotension, shock, and eventually death - within just a few hours.
Clostridial myonecrosis can be hard to diagnose early on, because it can look like cellulitis. And since untreated gas gangrene can spread rapidly, the diagnosis is usually made based on the severity of the infection and on how quickly it spreads.
Having said that, the diagnosis can be confirmed with an anaerobic tissue culture, but that usually takes a few days, which is far too long for individuals with gas gangrene.
Treatment of clostridial myonecrosis requires prompt and complete surgical excision of the necrotic tissue. This can sometimes include amputation of an affected extremity.
Individuals typically need supportive care to help manage fluids and maintain their hemodynamic status. High dose antibiotic treatment with penicillin V or clindamycin is also needed to kill the bacteria.
Sometimes additional broad spectrum antibiotics are used as well, especially in really ill-appearing individuals, in case there’s a co-infection.
Sometimes hyperbaric oxygen is used. That’s where a person is placed in a hyperbaric chamber, which contains 100% oxygen, because that amount of oxygen is deadly to Clostridium perfringens and other anaerobes.
Alright, as a quick recap. Clostridium perfringens is a gram-positive, spore-forming, obligate anaerobe that resides in the soil.
If it comes into contact with our food, it can cause food poisoning through toxin production. Clostridium perfringens food poisoning typically causes mild symptoms, lasts about a day, and resolves without antibiotics.
If Clostridium perfringens gets into an open wound, it can cause clostridial myonecrosis, or gas gangrene, which can be deadly within hours without surgical excision of the necrotic tissue, along with penicillin V and, in some cases, hyperbaric therapy.