WHAT IS C. DIFFICILE?
Clostridia are motile bacteria that are ubiquitous in nature and are especially prevalent in soil. Under the microscope after Gram staining, they appear as long drumsticks with a bulge located at their terminal ends. Clostridium difficile cells are Gram positive. Clostridium shows optimum growth when plated on blood agar at human body temperatures. When the environment becomes stressed, however, the bacteria produce spores that tolerate the extreme conditions that the active bacteria cannot. First described by Hall and O'Toole in 1935, "the difficult clostridium" was resistant to early attempts at isolation and grew very slowly in culture.
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C. difficile is a commensal bacterium of the human intestine in a minority of the population. Patients who have been staying long-term in a hospital or a nursing home have a higher likelihood of being colonized by this bacterium. In small numbers it does not result in disease of any significance. Antibiotics, especially those with a broad spectrum of activity, cause disruption of normal intestinal flora, leading to an overgrowth of C. difficile. This leads to pseudomembranous colitis.
It flourishes under these conditions. It is transmitted from person to person by the fecal-oral route. Because the organism forms heat-resistant spores, it can remain in the hospital or nursing home environment for long periods of time. It can be cultured from almost any surface in the hospital. Once spores are ingested, they pass through the stomach unscathed because of their acid-resistance. They change to their active form in the colon and multiply. It has been observed that several disinfectants commonly used in hospitals may fail to kill the bacteria, and may actually promote spore formation. However, disinfectants containing bleach are effective in killing the organisms. Pseudomembranous colitis caused by C. difficile is treated with antibiotics, for example, vancomycin, metronidazole, bacitracin or fusidic acid. C. difficile bacteria produce two powerful toxins that attack the lining of the colon.
The intestinal tract contains hundreds of kinds of bacteria (intestinal flora). Many are essential, helping to synthesize certain vitamins and stimulating the immune system. And some play a key role in suppressing the growth of harmful organisms. But when an antibiotic is used to treat an infection, it often destroys these beneficial bacteria as well as the bacteria that's causing the illness. Without enough healthy bacteria, dangerous pathogens such as
C. difficile can quickly grow out of control.
C. difficile is resistant to most antibiotics. Once it takes hold, C. difficile can produce two virulent toxins that attack the lining of the intestine. The toxins destroy cells and produce pseudomembranes - telltale patches (plaques) of inflammatory cells and decaying cellular debris on the interior surface of the colon.
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Risks for contracting C. difficile are greatest if your patients:
Are taking or have recently taken antibiotics.
Are 65 years of age or older. Older adults have a disproportionately high infection rate.
Have a serious underlying illness or weakened immune system.
(People with weakened immune systems are especially likely to have recurrent infections.)
Are or have recently been hospitalized, especially for an extended period.
In general, larger hospitals have higher infection rates than do smaller hospitals.
Live in a nursing home or longterm care facility. Often, the infection spreads when patients are
transferred from hospitals to other facilities.
Have had abdominal surgery.
Have a chronic colon disease such as inflammatory bowel disease or colorectal cancer.
Take prescription or over-the-counter antacids. By reducing stomach acid, these drugs may
allow C. difficile to pass more easily into the intestine.
SIGNS AND SYMPTOMS
Some people who are infected with C. difficile never become sick, though they can still spread the infection. Others have bouts of watery diarrhea, often with nausea and abdominal pain and cramping. Also, an increasing number of people develop colitis or pseudomembranous colitis - severe inflammations of the colon.
Signs and symptoms of these potentially life - threatening illnesses include:
Profuse, watery diarrhea - 10 or more bowel movements a day
Fever, often greater than 101 degree F
Abdominal pain, which may be severe
Blood or pus in the stool
Dehydration and weight loss
Most people develop C. difficile infection during or shortly after a course of antibiotics, but signs and symptoms may not appear for weeks or even months after treatment has stopped.
SCREENING AND DIAGNOSIS
Doctors often suspect C. difficile in anyone with diarrhea who has taken antibiotics in the past two months or when diarrhea develops a few days after hospitalization. In such cases, you're likely to have one or more of the following tests:
Toxins produced by C. difficile bacteria can usually be detected in a sample of the stool. The drawback to this test (immunoenzymatic assay) is that it isn't always reliable, occasionally producing false-negative results.
To help confirm a diagnosis of C. difficile infection, either a sigmoidoscopy or colonoscopy may be performed. In both procedures, the doctor uses a long, flexible tube with a camera on one end to examine the inside of the colon. A sigmoidoscopy looks only at the sigmoid colon and rectum - about the last two feet of intestine. A colonoscopy examines the entire colon. Both tests look for inflammation and pseudomembranes, which could suggest C. difficile infection.
Occasionally, the patient may have a computerized tomography (CT) scan, which provides detailed images of the colon. The scan can show a thickening of the wall of the colon, which is common in pseudomembranous colitis, but which is also seen in other conditions.
About a third of people with C. difficile have recurrences of their infection or are reinfected with a different strain of the C. difficile, usually within two months of the initial illness. Repeat infections tend to be more severe than the original disease and are more often fatal. Older adults and people with weakened immune systems are especially susceptible to recurring infections.
Complications of C. difficile infections include:
Dehydration. Severe diarrhea can lead to a significant loss of fluids and electrolytes. This makes it difficult for the body to function normally and can cause blood pressure to drop to dangerously low levels (hypotension).
Kidney failure. In some cases, dehydration can occur so quickly that the kidneys shut down (kidney failure).
A hole in the bowel (bowel perforation). This results from extensive damage to the lining of the large intestine. A perforated bowel can spill bacteria from the intestine into the abdominal cavity, leading to a life-threatening infection (peritonitis).
Toxic megacolon. In this condition, the colon becomes grossly distended when it is unable to expel gas and stool. Left untreated, the colon can rupture, causing bacteria from the colon to enter the abdominal cavity. A ruptured colon requires emergency surgery and in some cases may be fatal.
Death. Even mild to moderate C. difficile infections can quickly become fatal if not treated promptly with the appropriate medication.
Many people experience loose stools during or shortly after antibiotic therapy so diarrhea is not always C. difficile.
Patients should make an appointment to see their doctor as soon as possible if:
A.) the signs and symptoms last more than three days
B.) they are experiencing severe pain or cramping
C.) they are finding blood or pus in their stool
D.) they are having more than three bowel movements a day.
Probiotics. Some doctors prescribe probiotics - the word means "for life." These are dietary supplements that help restore a healthy balance to the intestinal tract. A natural yeast called Saccharomyces boulardii has proved effective in treating C. difficile infections in conjunction with antibiotics.
Surgery. For people with severe pain, organ failure or inflammation of the lining of the abdominal wall, surgery to remove the diseased portion of the bowel may be the only option.
If possible, stopping the antibiotic that triggered the infection is the first step in treating C. difficile. For some people, this may be enough to relieve symptoms. But most people require further treatment, which may include:
Antibiotics. In an ironic twist, the standard treatment for C. difficile is antibiotic therapy. Doctors usually prescribe oral metronidazole or vancomycin. These antibiotics eradicate C. difficile, allowing normal bacteria to flourish again in the intestine. Although metronidazole is often tried first, some recent studies suggest that it might be less effective than vancomycin in severe cases, and it cannot be used by women who are pregnant or breast-feeding.
On the other hand, vancomycin is expensive and may contribute to the growth of antibiotic-resistant bacteria. Both antibiotics kill only the active form of C. difficile, not the tough, long-lived spores it produces. Because the spores persist in the body after treatment, the infection can return, requiring a second or even a third round of antibiotics. Some people have repeat bouts of C. difficile for years.
The most important step in stopping C. difficile infections is to reserve antibiotics for times when they're really necessary. If patients do need an antibiotic, the doctor should prescribe one that has a narrow range and should be taken for the shortest time possible. Broad-spectrum antibiotics and those used for more than three to five days are far more likely to disrupt intestinal bacteria.
Also, consider taking probiotic supplements - available at natural foods stores and many pharmacies - or eating yogurt before, during and after antibiotic treatment. This helps replace the beneficial bacteria that antibiotics destroy. Only Saccharomyces boulardii has proved effective in C. difficile infections, however.
Hospital staff should wear disposable gloves - and disposable gowns if soiling of clothes is likely - when treating people with C. difficile infections. They wash their hands thoroughly before and after treating each patient, after removing gloves, and after touching surfaces that might be contaminated.
Alcohol-based hand gels, which are commonly used in health care institutions, may not effectively destroy C. difficile spores. Visitors should wash their hands with soap and warm water before entering and after leaving the room of a patient with a C. difficile infection. People who have a C. difficile infection have a private room or share a room with someone who has the same illness. All room surfaces should be carefully disinfected with a product that contains chlorine bleach.