Clostridium difficile (klos-TRID-e-um dif-uh-SEEL), often called C. difficile or C. diff, is a bacterium that can cause symptoms ranging from diarrhea to life-threatening inflammation of the colon.
Illness from C. difficile most commonly affects older adults in hospitals or in long-term care facilities and typically occurs after use of antibiotic medications. However, studies show increasing rates of C. difficile infection among people traditionally not considered high risk, such as younger and healthy individuals without a history of antibiotic use or exposure to health care facilities.
Each year in the United States, about a half million people get sick from C. difficile, and in recent years, C. difficile infections have become more frequent, severe and difficult to treat.
Some people carry the bacterium C. difficile in their intestines but never become sick, though they may still spread the infection. Signs and symptoms usually develop within five to 10 days after starting a course of antibiotics, but may occur as soon as the first day or up to two months later.
Mild to moderate infection
The most common symptoms of mild to moderate C. difficile infection are:
- Watery diarrhea three or more times a day for two or more days
- Mild abdominal cramping and tenderness
In severe cases, people tend to become dehydrated and may need hospitalization. C. difficile causes the colon to become inflamed (colitis) and sometimes may form patches of raw tissue that can bleed or produce pus (pseudomembranous colitis). Signs and symptoms of severe infection include:
- Watery diarrhea 10 to 15 times a day
- Abdominal cramping and pain, which may be severe
- Rapid heart rate
- Blood or pus in the stool
- Loss of appetite
- Weight loss
- Swollen abdomen
- Kidney failure
- Increased white blood cell count
When to see a doctor
Some people have loose stools during or shortly after antibiotic therapy. This may be due to C. difficile infection. See your doctor if you have three or more watery stools a day and symptoms lasting more than two days or if you have a new fever, severe abdominal pain or cramping, or blood in your stool.
C. difficile bacteria are found throughout the environment — in soil, air, water, human and animal feces, and food products, such as processed meats. A small number of healthy people naturally carry the bacteria in their large intestine and don't have ill effects from the infection.
C. difficile infection is most commonly associated with health care and recent antibiotic use, occurring in hospitals and other health care facilities where a much higher percentage of people carry the bacteria. However, studies show increasing rates of community-associated C. difficile infection, which occurs among populations traditionally not considered high risk, such as children and people without a history of antibiotic use or recent hospitalization.
Spores from C. difficile bacteria are passed in feces and spread to food, surfaces and objects when people who are infected don't wash their hands thoroughly. These spores can persist in a room for weeks or months. If you touch a surface contaminated with C. difficile spores, you may then unknowingly swallow the bacteria.
Your intestines contain about 100 trillion bacterial cells and up to 2,000 different kinds of bacteria, many of which help protect your body from infection. When you take an antibiotic to treat an infection, these drugs tend to destroy some of the normal, helpful bacteria in addition to the bacteria causing the infection. Without enough healthy bacteria to keep it in check, C. difficile can quickly grow out of control. The antibiotics that most often lead to C. difficile infections include fluoroquinolones, cephalosporins, penicillins and clindamycin.
Once established, C. difficile can produce toxins that attack the lining of the intestine. The toxins destroy cells and produce patches (plaques) of inflammatory cells and decaying cellular debris inside the colon and cause watery diarrhea.
Emergence of a new strain
An aggressive strain of C. difficile has emerged that produces far more toxins than other strains do. The new strain may be more resistant to certain medications and has shown up in people who haven't been in the hospital or taken antibiotics. This strain of C. difficile has caused several outbreaks of illness since 2000.
Although people — including children — with no known risk factors have gotten sick from C. difficile, certain factors increase your risk.
Taking antibiotics or other medications
Medication-associated risk factors include:
- Currently taking or having recently taken antibiotics
- Taking broad-spectrum antibiotics that target a wide range of bacteria
- Using multiple antibiotics
- Taking antibiotics for a long time
- Taking medications to reduce stomach acid, including proton pump inhibitors
Staying in a health care facility
The majority of C. difficile cases occur in, or after exposure to, health care settings — including hospitals, nursing homes and long-term care facilities — where germs spread easily, antibiotic use is common and people are especially vulnerable to infection. In hospitals and nursing homes, C. difficile spreads mainly on hands from person to person, but also on cart handles, bedrails, bedside tables, toilets, sinks, stethoscopes, thermometers — even telephones and remote controls.
Having a serious illness or medical procedure
If you have a serious illness, such as inflammatory bowel disease or colorectal cancer, or a weakened immune system as a result of a medical condition or treatment (such as chemotherapy), you're more susceptible to a C. difficile infection. Your risk of C. difficile infection is also greater if you've had abdominal surgery or a gastrointestinal procedure.
Older age is also a risk factor for C. difficile infection. In one study, the risk of becoming infected with C. difficile was 10 times greater for people age 65 and older compared with younger people.
After having a previous C. difficile infection, your chances of having a recurring infection can be up to 20 percent, and the risk increases further with every subsequent infection.
Complications of C. difficile infections include:
- Dehydration. Severe diarrhea can lead to a significant loss of fluids and electrolytes. This makes it difficult for your body to function normally and can cause blood pressure to drop to dangerously low levels.
- Kidney failure. In some cases, dehydration can occur so quickly that kidney function rapidly deteriorates (kidney failure).
- Toxic megacolon. In this rare condition, your colon is unable to expel gas and stool, causing it to become greatly distended (megacolon). Left untreated, your colon may rupture, causing bacteria from the colon to enter your abdominal cavity. An enlarged or ruptured colon requires emergency surgery and may be fatal.
- A hole in your large intestine (bowel perforation). This is rare and results from extensive damage to the lining of your large intestine or after toxic megacolon. A perforated bowel can spill bacteria from the intestine into your abdominal cavity, leading to a life-threatening infection (peritonitis).
- Death. Even mild to moderate C. difficile infections can quickly progress to a fatal disease if not treated promptly.
Doctors often suspect C. difficile in anyone with diarrhea who has taken antibiotics within 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 your stool. Several main types of lab tests exist, and they include:
- Enzyme immunoassay. The enzyme immunoassay (EIA) test is faster than other tests but isn't sensitive enough to detect many infections and has a higher rate of falsely normal tests.
- Polymerase chain reaction. This sensitive molecular test can rapidly detect the C. difficile toxin B gene in a stool sample and is highly accurate.
- GDH/EIA. Some hospitals use a glutamate dehydrogenase (GDH) in conjuction with an EIA test. GDH is a very sensitive assay and can accurately rule out the presence of C. difficile in stool samples.
- Cell cytotoxicity assay. A cytotoxicity test looks for the effects of the C. difficile toxin on human cells grown in a culture. This type of test is sensitive, but it is less widely available, more cumbersome to do and requires 24 to 48 hours for test results. Some hospitals use both the EIA test and cell cytotoxicity assay to ensure accurate results.
Testing for C. difficile is unnecessary if you're not having diarrhea or watery stools, and is not helpful for follow-up treatment.
In rare instances, to help confirm a diagnosis of C. difficile infection and look for alternatives, your doctor may examine the inside of your colon. This test (flexible sigmoidoscopy or colonoscopy) involves inserting a flexible tube with a small camera on one end into your colon to look for areas of inflammation and pseudomembranes.
If your doctor is concerned about possible complications of C. difficile, he or she may order an abdominal X-ray or a computerized tomography (CT) scan, which provides images of your colon. The scan can detect the presence of complications such as thickening of the colon wall, expanding of the bowel, or more rarely, a hole (perforation) in the lining of your colon.
The first step in treating C. difficile is to stop taking the antibiotic that triggered the infection, when possible. Depending on the severity of your infection, treatment may include:
Antibiotics. Ironically, the standard treatment for C. difficile is another antibiotic. These antibiotics keep C. difficile from growing, which in turn treats diarrhea and other complications.
For mild to moderate infection, doctors usually prescribe metronidazole (Flagyl), taken by mouth. Metronidazole is not approved by the FDA for C. difficile infection, but has been shown to be effective in mild to moderate infection. Side effects of metronidazole include nausea and a bitter taste in your mouth.
For more severe and recurrent cases, vancomycin (Vancocin), also taken by mouth, may be prescribed.
Another oral antibiotic, fidaxomicin (Dificid), has been approved to treat C. difficile. In one study, the recurrence rate of C. difficile in people who took fidaxomicin was lower than among those who took vancomycin. However, fidaxomicin costs considerably more than metronidazole and vancomycin. Common side effects of vancomycin and fidaxomicin include abdominal pain and nausea.
- Surgery. For people with severe pain, organ failure, toxic megacolon or inflammation of the lining of the abdominal wall, surgery to remove the diseased portion of the colon may be the only option.
Up to 20 percent of people with C. difficile get sick again, either because the initial infection never went away or because they're reinfected with a different strain of the bacteria. But after two or more recurrences, rates of further recurrence increase up to 65 percent.
Your risk of recurrence is higher if you:
- Are older than 65
- Are taking other antibiotics for a different condition while being treated with antibiotics for C. difficile infection
- Have a severe underlying medical disorder, such as chronic kidney failure, inflammatory bowel disease or chronic liver disease
Treatment for recurrent disease may include:
- Antibiotics. Antibiotic therapy for recurrence may involve one or more courses of a medication (typically vancomycin), a gradually tapered dose of medication or an antibiotic given once every few days, a method known as a pulsed regimen. The effectiveness of antibiotic therapy declines with each subsequent recurrence.
Fecal microbiota transplant (FMT). Also known as a stool transplant, FMT is emerging as an alternative strategy for treating recurrent C. difficile infections. Though not yet approved by the FDA, clinical studies of FMT are currently underway.
FMT restores healthy intestinal bacteria by placing another person's (donor's) stool in your colon, using a colonoscope or nasogastric tube. Donors are screened for medical conditions, their blood is tested for infections, and stools are carefully screened for parasites, viruses and other infectious bacteria before being used for FMT.
Research has shown FMT has a success rate higher than 90 percent for treating C. difficile infections.
- Probiotics. Probiotics are organisms, such as bacteria and yeast, which help restore a healthy balance to the intestinal tract. A yeast called Saccharomyces boulardii, in conjunction with antibiotics, might help prevent further recurrent C. difficile infections.
Supportive treatment for diarrhea includes:
- Plenty of fluids. Choose fluids containing water, salt and sugar, such as diluted fruit juice, soft drinks and broths.
- Good nutrition. If you have watery diarrhea, eat starchy foods, such as potatoes, noodles, rice, wheat and oatmeal. Other good choices are saltine crackers, bananas, soup and boiled vegetables. If you aren't hungry, you may need a liquid diet at first. After your diarrhea clears up, you may have temporary difficulty digesting milk and milk-based products.
To help prevent the spread of C. difficile, hospitals and other health care facilities follow strict infection-control guidelines. If you have a friend or family member in a hospital or nursing home, don't be afraid to remind caregivers to follow the recommended precautions.
Preventive measures include:
- Hand-washing. Health care workers should practice good hand hygiene before and after treating each person in their care. In the event of a C. difficile outbreak, using soap and warm water is a better choice for hand hygiene, because alcohol-based hand sanitizers do not effectively destroy C. difficile spores. Visitors also should wash their hands with soap and warm water before and after leaving the room or using the bathroom.
- Contact precautions. People who are hospitalized with C. difficile have a private room or share a room with someone who has the same illness. Hospital staff and visitors wear disposable gloves and isolation gowns while in the room.
- Thorough cleaning. In any setting, all surfaces should be carefully disinfected with a product that contains chlorine bleach. C. difficile spores can survive routine cleaning products that don't contain bleach.
- Avoid unnecessary use of antibiotics. Antibiotics are sometimes prescribed for viral illnesses that aren't helped by these drugs. Take a wait-and-see attitude with simple ailments. If you do need an antibiotic, ask your doctor to prescribe one that has a narrow range and that you take for the shortest time possible.