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C. difficile infection

Medically reviewed by Last updated on Sep 1, 2023.


Clostridioides difficile (klos-TRID-e-oi-deez dif-uh-SEEL) is a bacterium that causes an infection of the colon, the longest part of the large intestine. Symptoms can range from diarrhea to life-threatening damage to the colon. The bacterium is often called C. difficile or C. diff.

Illness from C. difficile often occurs after using antibiotic medicines. It mostly affects older adults in hospitals or in long-term care settings. People not in care settings or hospitals also can get C. difficile infection. Some strains of the bacterium that can cause serious infections are more likely to affect younger people.

The bacterium used to be called Clostridium (klos-TRID-e-um) difficile.


Symptoms often begin within 5 to 10 days after starting an antibiotic. But symptoms can occur as soon as the first day or up to three months later.

Mild to moderate infection

The most common symptoms of mild to moderate C. difficile infection are:

Severe infection

People who have a severe C. difficile infection tend to lose too much bodily fluid, a condition called dehydration. They might need to be treated in a hospital for dehydration. C. difficile infection can cause the colon to become inflamed. It sometimes can form patches of raw tissue that can bleed or make pus. Symptoms of severe infection include:

C. difficile infection that is severe and sudden can cause the colon to become inflamed and get larger, called toxic megacolon. And it can cause a condition called sepsis where the body's response to an infection damages its own tissues. People who have toxic megacolon or sepsis are admitted to an intensive care unit in the hospital. But toxic megacolon and sepsis aren't common with a C. difficile infection.

When to see a doctor

Some people have loose stools during or shortly after antibiotic therapy. This may be caused by C. difficile infection. Make a health care appointment if you have:


C. difficile bacteria enter the body through the mouth. They can begin reproducing in the small intestine. When they reach the part of the large intestine, called the colon, the bacteria can release toxins that damage tissues. These toxins destroy cells and cause watery diarrhea.

Outside the colon, the bacteria aren't active. They can live for a long time in places such as:

When bacteria once again find their way into a person's digestive system, they become active again and cause infection. Because C. difficile can live outside the body, the bacteria spread easily. Not washing hands or cleaning well make it easy to spread the bacteria.

Some people carry C. difficile bacteria in their intestines but never get sick from it. These people are carriers of the bacteria. They can spread infections without being sick.

Colon and rectum

The colon is a long tube-like organ in the abdomen. It's the largest part of the large intestine. The colon carries waste to be expelled from the body. The rectum makes up the last several inches of the colon.

Risk factors

People who have no known risk factors have gotten sick from C. difficile. But certain factors increase the risk.

Taking antibiotics or other medicines

The intestines house a wide range of bacteria. Many of them help protect the body from infection. Antibiotics that treat an infection tend to destroy some of the helpful bacteria in the body as well as the bacteria causing the infection.

Without enough helpful bacteria to keep it in check, C. difficile can grow out of control quickly. Any antibiotic can cause C. difficile infection. But the antibiotics that most often lead to C. difficile infection include:

Taking a proton pump inhibitor, a type of medicine used to cut stomach acid, also may increase the risk of C. difficile infection.

Staying in a health care setting

Most C. difficile infections occur in people who are in or have recently been in health care settings. These include hospitals, nursing homes and long-term care facilities. These are places where germs spread easily, antibiotic use is common and people's health puts them at high risk of getting an infection. In hospitals and nursing homes, C. difficile spreads on:

Having a serious illness or medical procedure

Certain medical conditions or procedures can up the risk of getting a C. difficile infection, including:

Other risk factors

Older age is a risk factor. 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.

Having one C. difficile infection increases the chance of having another one. The risk increases with each infection.


Complications of C. difficile infection include:


To protect against C. difficile, don't take antibiotics unless you need them. Sometimes, you may get a prescription for antibiotics to treat conditions not caused by bacteria, such as viral illnesses. Antibiotics don't help infections caused by viruses.

If you need an antibiotic, ask if you can get a prescription for a medicine that you take for a shorter time or is a narrow-spectrum antibiotic. Narrow-spectrum antibiotics target a limited number of bacteria types. They're less likely to affect healthy bacteria.

To help prevent the spread of C. difficile, hospitals and other health care settings follow strict rules to control infections. If you have a loved one in a hospital or nursing home, follow the rules. Ask questions if you see caregivers or other people not following the rules.

Measures to prevent C. difficile include:


A diagnosis of C. difficile infection is based on having:

People who have regular, formed stools should not be tested for C. difficile infection. Some people get C. difficile infection without having taken antibiotics. So recent use of antibiotics is not needed for making a diagnosis of C. difficile infection.

Stool tests

If C. difficile infection is suspected, one or more tests of a stool sample can show either the toxins or strains of the bacteria that produce toxins.

Colon exam

Rarely, to help confirm a diagnosis of C. difficile infection, a health care provider might check the inside of the colon. Tests used are either flexible sigmoidoscopy or colonoscopy. The tests involve putting a flexible tube with a small camera on one end into the colon to look for problem areas. These tests also can look for other causes of the symptoms.

Imaging tests

An X-ray of the stomach area or a CT scan can look for possible complications of C. difficile infection. These imaging tests can detect:


Treatments are used only for symptoms of infection. People who carry the bacteria but aren't sick don't get treated.


If C. difficile infection is related to an antibiotic, a health care provider will likely stop its use. Often, however, an antibiotic is needed to treat another infectious condition. A switch to another antibiotic might be less likely to cause diarrhea related to C. difficile infection.

Antibiotics are the main treatment for C. difficile infection. Commonly used antibiotics include:

Metronidazole (Flagyl) may be used with vancomycin to treat serious C. difficile infection.


Surgery to remove the diseased part of the colon may be needed if there's:

Treatment for repeat infection

About 25% of people treated for C. difficile infection get sick again. The reason might be that the first infection never went away or that bacteria cause a new infection. The risk increases with each C. difficile infection. After three or more infections, the risk of another infection is greater than 50%.

Risk of repeat infection is higher for people who:

Treatment for C. difficile infection that comes back might include the following:

Lifestyle and home remedies

Supportive treatment for diarrhea includes:

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