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, more than 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 can still spread the infection. C. difficile illness usually develops during or within a few months after a course of antibiotics.

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

Severe infection

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
  • Fever
  • Blood or pus in the stool
  • Nausea
  • Dehydration
  • 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, 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.

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. The bacteria produce spores that can persist in a room for weeks or months. If you touch a surface contaminated with C. difficile, you may then unknowingly swallow the bacteria.

Your intestines contain millions of bacteria, many of which help protect your body from infection. But when you take an antibiotic to treat an infection, the drug can destroy some of the normal, helpful bacteria as well as the bacteria causing the illness. Without enough healthy bacteria, C. difficile can quickly grow out of control. The antibiotics that most often lead to C. difficile infections include fluoroquinolones, cephalosporins, clindamycin and penicillins.

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 (PPIs)

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 condition, your colon becomes unable to expel gas and stool, causing it to become greatly distended (megacolon). Left untreated, your colon can rupture, causing bacteria from the colon to enter your abdominal cavity. A 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. 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 recently taken antibiotics or when diarrhea develops a few days after hospitalization. In such cases, you're likely to have one or more of the following tests.

Stool 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. Most labs use the enzyme immunoassay (EIA) test, which 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. It's now being adapted by several laboratories and becoming more widely available.
  • 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 more than 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.

Colon examination

In rare instances, to help confirm a diagnosis of C. difficile infection, 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.

Imaging tests

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 treats diarrhea and other complications.

    For mild to moderate infection, doctors usually prescribe metronidazole (Flagyl), taken by mouth. Metronidazole is not FDA approved 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 or inflammation of the lining of the abdominal wall, surgery to remove the diseased portion of the colon may be the only option.

Recurrent infection

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 one 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. For a first recurrence, the effectiveness of antibiotic therapy is around 60 percent and further 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. Donor stools are carefully and repeatedly screened for parasites, viruses, bacteria and certain antibodies before being used for an FMT.

    Research has shown FMT has a success rate higher than 90 percent for treating C. difficile infections. One small, randomized, controlled trial stopped early because the results were so positive, with a 94 percent success rate overall.

  • 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 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.
  • Expertise. Mayo Clinic specializes in treating people with difficult cases of C. difficile who haven't responded to standard medical treatments or who have developed complications such as an inflamed colon.
  • Cutting-edge medicine. Mayo Clinic uses the polymerase chain reaction (PCR) test to confirm C. difficile infection, the most accurate diagnostic test available. The high sensitivity of PCR, together with its rapid turnaround time, allows prompt treatment for people with C. difficile infection, likely reducing opportunity for spreading infection and improving outcomes.

    A new and emerging treatment for recurrent or stubborn C. difficile infections, the fecal microbiota transplant (FMT), has been performed at Mayo Clinic with a success rate higher than 90 percent. FMT therapy involves infusing healthy donor stools in people with C. difficile infections. Mayo Clinic performs extensive testing of donors and recipients before performing the procedure and offers the choice of related (family) or standard donors. Because donor testing typically isn't covered by insurance, Mayo Clinic has a standard donor pool to help reduce the cost to potential recipients.

  • Team approach. Doctors who specialize in digestive and infectious diseases work closely with laboratory medicine and scientists specializing in the gut microbiome and individualized medicine to diagnose and treat your condition.
  • Research. The Division of Gastroenterology and Hepatology at Mayo Clinic in Rochester, Minn., has opened a clinic especially dedicated to researching and treating C. difficile infection, including studies of the gut microflora and new therapies for C. difficile infection.

Mayo Clinic in Rochester, Minn., ranks No. 1 for digestive disorders in the U.S. News & World Report Best Hospitals rankings. Mayo Clinic in Scottsdale, Ariz., and Mayo Clinic in Jacksonville, Fla., are ranked high performing for digestive disorders by U.S. News & World Report.

At Mayo Clinic, we assemble a team of specialists who take the time to listen and thoroughly understand your health issues and concerns. We tailor the care you receive to your personal health care needs. You can trust our specialists to collaborate and offer you the best possible outcomes, safety and service.

Mayo Clinic is a not-for-profit medical institution that reinvests all earnings into improving medical practice, research and education. We're constantly involved in innovation and medical research, finding solutions to improve your care and quality of life. Your doctor or someone on your medical team is likely involved in research related to your condition.

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Mayo Clinic works with hundreds of insurance companies and is an in-network provider for millions of people. In most cases, Mayo Clinic doesn't require a physician referral. Some insurers require referrals or may have additional requirements for certain medical care. All appointments are prioritized on the basis of medical need.

Specialists in gastroenterology and hepatology and infectious diseases at Mayo Clinic in Arizona care for patients who have C. difficile.

For appointments or more information, call the Central Appointment Office at 800-446-2279 (toll-free) 8 a.m. to 5 p.m. Mountain Standard Time, Monday through Friday or complete an online appointment request form.

Specialists in gastroenterology and hepatology and infectious diseases at Mayo Clinic in Florida care for patients who have C. difficile.

For appointments or more information, call the Central Appointment Office at 904-953-0853 8 a.m. to 5 p.m. Eastern time, Monday through Friday or complete an online appointment request form.

Specialists in gastroenterology and hepatology and infectious diseases in Minnesota care for patients who have C. difficile.

For appointments or more information, call the Central Appointment Office at 507-538-3270 7 a.m. to 6 p.m. Central time, Monday through Friday or complete an online appointment request form.

Mayo researchers are involved in studies evaluating the epidemiology, risk factors and treatment of C. difficile infection. Studies are ongoing to characterize the fecal microbial composition in the colon to develop tools that can predict response to treatment and the risk of recurrent infection.

Mayo Publications

See a list of publications by Mayo Clinic authors about C. difficile on PubMed, a service of the National Library of Medicine.

Jul. 16, 2013