Overview

C. diff, short for Clostridioides difficile, is a bacterium that can cause a serious infection in your colon, causing symptoms like diarrhea, nausea, and bloating.

Many people carry it without any problems. But if the healthy bacteria in your intestines are disrupted, often after taking antibiotics, C. diff can grow out of control. When it multiplies too much, it releases toxins that irritate and inflame the colon, leading to illness.

If not treated, C. diff can cause serious complications, including severe dehydration, kidney damage, a tear in the colon, or a life-threatening bloodstream infection (sepsis).

How Common Is It?

C. diff is one of the most common infections in hospitals and other healthcare settings in the United States.

• Around 500,000 Americans develop C. diff each year.
• Although many cases start in hospitals or nursing homes, a large number also occur in the community, often after antibiotic use.
• Older adults, especially those over 65, are at the highest risk for severe illness and recurrence.
• The CDC reports that C. diff causes tens of thousands of deaths annually.

Symptoms

C. diff infection can range from mild to life-threatening. Symptoms typically begin within days to weeks after starting antibiotics, but can also appear up to three months later.

Mild to moderate symptoms:

• Diarrhea (3 or more times a day)
• Stomach cramping or pain (often in the lower belly)
• Nausea
• Mild fever
• Loss of appetite
• Foul-smelling stool

Severe symptoms:

• Diarrhea up to 10–15 times a day
• Blood or pus in stool
• High fever
• Swollen or painful abdomen
• Rapid heart rate
• Dehydration (dry mouth, dizziness, low urine output)
• Confusion or weakness

If symptoms worsen or include blood in the stool, severe pain, or signs of dehydration, seek medical attention immediately. Serious complications can include kidney failure, toxic megacolon, colon rupture, or sepsis.

Causes

A C. diff infection is primarily caused by an overgrowth of the bacteria in your colon, which then produces toxins that lead to symptoms. This overgrowth often happens after taking antibiotics because these medications kill off both good and bad bacteria, disrupting the natural balance in your gut and giving C. diff an opportunity to multiply.

Transmission

C. diff can also be spread from person to person through fecal-oral transmission. The bacteria form resilient spores that can survive on surfaces like bed rails, toilet handles, and hands for a long time.

If someone touches a contaminated surface and then their mouth, they can ingest the bacteria. This is why good hand hygiene and proper cleaning are essential for preventing its spread, especially in hospitals and nursing homes where patients are more vulnerable.

Risk Factors

Certain situations increase the likelihood of developing C. diff.

• Recent antibiotic use: Especially broad-spectrum antibiotics like clindamycin, cephalosporins, and fluoroquinolones.
• Age 65 or older.
• Hospital or nursing home stays.
• Weakened immune system: Conditions like HIV, cancer treatment, or organ transplants can make it harder for your body to fight off the infection.
• Gastrointestinal procedures: Any surgery or tests involving the intestines can slightly increase your risk.
• Long-term use of proton pump inhibitors (PPIs): These are medications for acid reflux that can lower stomach acid, which typically helps protect against infections. Some studies suggest a potential link between long-term use and increased risk.

Having one or more risk factors does not guarantee infection, but it increases the chances, especially if several risk factors occur together.

Diagnosis

• C. diff is usually diagnosed with a stool test.
• Other tests may include:
  • Blood tests don't directly detect the bacteria, but they can show signs of an infection, such as a high white blood cell count. A very high white blood cell count can indicate a more severe infection, especially if it's accompanied by persistent diarrhea, cramping, or signs of dehydration.
  • Colonoscopy or sigmoidoscopy – In severe cases, doctors may look inside the colon using a flexible tube with a camera. This allows them to check for inflammation and, if needed, take a small tissue sample. A colonoscopy examines the entire colon, while a sigmoidoscopy looks at the lower section.
  • CT scan – If complications are suspected, a CT scan can provide detailed images of the intestines and surrounding areas.

Treatment

Treatment for a C. diff infection depends on the severity of your symptoms. Mild cases can often be managed at home, while more serious infections may require hospitalization.

The first step in treatment is usually to stop the antibiotic that may have caused the infection, if possible. After that, specific antibiotics are used to treat the C. diff itself. The most common medications are:

• Fidaxomicin (Dificid): This is a powerful oral antibiotic that specifically targets C. diff in the gut without disrupting too much of the normal, healthy bacteria. It's often taken for 10 days and is considered a first-choice treatment.
• Vancomycin: This oral antibiotic also targets C. diff in the intestines and is typically taken for 10 days.

For people who have repeated infections or don’t respond to antibiotics, doctors may consider a fecal microbiota transplant (FMT). This procedure involves introducing healthy donor stool into the colon to restore the natural balance of gut bacteria and prevent future infections.

In rare and severe cases where the colon is badly damaged, surgery may be necessary to remove part or all of the colon.

Prevention

Preventing a C. diff infection is far easier than treating one, especially for people who have had it before or are at high risk.

One of the most important preventive measures is to be cautious with antibiotic use. These medications can disrupt the delicate balance of bacteria in your gut, which creates an opportunity for C. diff to grow. It’s crucial to use antibiotics only when they are truly necessary, as prescribed by a doctor, and to complete the entire course of treatment.