Clostridial Infections Overview
Clostridia are bacteria that normally reside in the intestine of 3 to 8% of healthy adults and even more newborns. Clostridia also reside in animals, soil, and decaying vegetation. These bacteria do not require oxygen to live. That is, they are anaerobes.
There are many different species of clostridia. They cause disease in different ways, depending on the species:
The bacteria may produce a toxin in food, which is then consumed, as occurs in foodborne botulism.
The bacteria may be consumed in food, then multiply and produce a toxin, as occurs in Clostridium perfringens food poisoning.
Clostridia spores (inactive, or dormant, forms of the bacteria) may enter the body through a wound and produce a toxin, as occurs in tetanus.
Use of antibiotics may enable clostridia, which may already be present in the intestine, to overgrow and produce two toxins, as occurs in antibiotic-associated Clostridium difficile—induced diarrhea and colitis.
Clostridial bacteria may enter through a wound, multiply, and produce a toxin that destroys tissue, as occurs in gas gangrene.
Clostridia can infect the gallbladder, colon, and female reproductive organs. Rarely, one species, Clostridium sordellii, causes toxic shock syndrome in women who have infections of the reproductive organs.
Botulism can develop when people eat food that contains botulinum toxin, produced by Clostridium botulinum. Usually, botulism results from eating uncooked or undercooked food because heat (cooking) destroys the toxin. Stored foods, if inadequately cooked before they were stored, can cause botulism. Also, refrigerating food does not make food safe because the bacteria can produce some toxins at typical refrigerator temperatures.
Botulinum toxin enters the bloodstream from the small intestine and is carried to nerves. This toxin prevents nerves from sending impulses to muscles. About 18 to 36 hours after consuming the toxin, people become tired and dizzy. Their mouth becomes dry. They may feel nauseated and vomit. They may have abdominal cramps and diarrhea. The abdomen may swell (distend), and constipation may develop. Muscles of the face become slack or paralyzed, causing the eyelids and face to droop and vision to blur. Swallowing and talking become difficult. The muscle weakness then spreads to the upper torso and downward. The muscles involved in breathing may weaken—a problem that may become life threatening.
If people think they may have botulism, they should go to a hospital immediately. To help eliminate any unabsorbed toxin, doctors may give them activated charcoal by mouth or through a tube passed through the nose or mouth and into the stomach. A substance that blocks the action of the toxins (antitoxin) is given as soon as possible after botulism has been diagnosed. If breathing problems begin, people are transferred to an intensive care unit and may be temporarily placed on a ventilator.
This type of food poisoning can develop when people eat food (usually beef) that contains bacteria (rather than the bacteria’s toxin). The bacteria develop from spores, which can survive the heat of cooking. If food that contains spores is not eaten soon after it is cooked, the spores develop into bacteria, which then multiply in the food. If the food is served without adequate reheating, the bacteria are consumed. They multiply in the small intestine and produce a toxin that causes watery diarrhea and abdominal cramping.
This type of food poisoning is usually mild and resolves within 24 hours. But rarely, food poisoning is severe, particularly in the very young and in older people.
Rarely, certain strains of these bacteria produce a toxin that damages the intestine and causes an infection called necrotizing enteritis, which is often fatal.
To prevent food poisoning, people should promptly refrigerate leftover cooked meat and reheat it thoroughly before serving.
Treatment includes drinking lots of fluids and resting. Antibiotics are not used.
In this disorder, toxins produced by the bacteria cause inflammation of the colon (colitis), usually after antibiotics are taken to treat an infection (see also Clostridium difficile -Induced Colitis). Antibiotics may destroy some of the bacteria that normally reside in the intestine. If enough are destroyed, Clostridium difficile may overgrow. These bacteria may already be present in the intestine. Or people may get them from other people, pets, or the environment. Being very young or very old, staying in a hospital or nursing home, or having one or more severe disorders increases the risk of this disorder.
When the bacteria overgrow, they release two toxins.
Usually, symptoms begin 5 to 10 days after people start taking antibiotics. Diarrhea may be watery, slightly loose, or bloody. Many people have abdominal cramps or pain, but nausea and vomiting are rare.
If this disorder develops after a person has started taking antibiotics, the antibiotics are stopped unless they are essential. In such cases, symptoms usually stop within 10 to 12 days. If they persist, drugs, such as cholestyramine resin, may be used. If symptoms are severe, the antibiotic metronidazole, vancomycin, or sometimes fidaxomicin is usually used.
A fecal transplant is another option for people who have severe, recurring symptoms. About a cup (200 to 300 mL) of fecal material (stool) from a healthy donor is placed in the person's colon. The fecal transplant can be given as an enema, through a tube inserted through the nose into the digestive tract, or through a tube inserted through the anus into the large intestine (colonoscope). The donor's stool is first tested to make sure that it does not contain any organisms that cause disease. Doctors think that fecal material from a donor restores the normal balance of bacteria in the colon of a person with Clostridium difficile–induced colitis.
Because clostridia thrive when no oxygen is present, they reproduce well in tissues that have been severely damaged and in wounds that are very deep. Such tissues have poor blood flow and thus low oxygen levels. Risk of infection is highest when people have wounds that contain dead tissue (see also Necrotizing Skin Infections).
One species, Clostridium perfringens, can cause infection within hours after an injury, but sometimes infection takes several days to appear.
Clostridial soft-tissue infections may involve the
Sometimes the bacteria in these tissues produce large amounts of gas as a waste product. The gas can form bubbles and blisters in tissue. Often, the infection blocks small blood vessels. As a result, the infected tissue dies, leading to gangrene. The dead tissue enables the clostridial infection to spread even faster. Gangrene is more likely to develop when muscle is infected than when skin is infected.
The infected area is usually obvious.
Shallow skin infections may not be very painful, but deeper infections into muscle usually are. Foul-smelling material may drain from wounds or blisters.
People eventually become severely ill and develop shock and kidney failure. Without treatment, nearly all people who have a clostridial muscle infection die.
Prompt treatment is essential. Doctors quickly give antibiotics and surgically remove the dead and severely infected tissue.