C. Difficile Infection

1 What is C. Difficile Infection?

Clostridium difficile (klos-TRID-e-um dif-uh-SEEL), often called C. difficile or C. diff, is a Gram +ve bacterium that causes diarrhea and more serious infection of the colon known as C. difficile colitis, a life threatening inflammation of the colon.

C. difficile infection primarily occurs in hospitalized older adults. Antibiotic therapy disturbs normal flora in the intestine and is a key risk factor for this infection.

Over the years, higher incidence of C. difficile infection has been observed among younger and healthy individuals without a history of antibiotic use or exposure to health care facilities.

It affects more than a half million people every year and of lately C. difficile infections have shown trends of increased frequency, severity and unresponsiveness to treatment.

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2 Symptoms

Generally, the symptoms start appearing during or within a few months after a course of antibiotics. Healthy people who carry C. difficile in their intestines can still spread the infection. 

Mild to moderate infection

Patients with mild to moderate C. difficile infection present with the following symptoms:

  • Watery diarrhea 3 or more times a day for 2 or more days.
  • Mild abdominal cramps and tenderness.
  • Severe infection

Severe infections are characterized by dehydration often requiring hospitalization. The colon may become inflamed (colitis), sometimes progressing to pseudomembranous colitis, a condition in which patches of raw tissue that can bleed or produce pus are formed in the colon.

Patients with severe C. difficile infection present with the following symptoms:

  • Watery diarrhea 10 to 15 times a day
  • Severe abdominal cramps and pain
  • Fever
  • Blood or pus in the stool
  • Nausea
  • Dehydration
  • Loss of appetite
  • Weight loss
  • Kidney failure
  • Increased white blood cell count
  • When to see a doctor

Loose stools during or shortly after antibiotic therapy could be due to C. difficile infection. See your doctor if loose motions (2 or more times a day) last more than two days or if you develop fever, severe abdominal pain or observe blood in your stool.

3 Causes

C Difficile infection is caused by contact with the C. difficile bacteria, which can be found in soil, air, water, feces, and food products such as meats.

Many healthy individuals who harbor the bacteria in their intestines do not exhibit any symptom.

Who is at risk?

While the infection is a common occurrence in hospitalized adults, “not high risk” populations such as children and people without a history of antibiotic use or recent hospitalization are showing increased rates of incidence.
Common route for transmission of the infection is fecal-oral route and lack of proper hand washing is a major cause of its transmission.

When the normal flora of intestine is disturbed by factors such as antibiotics, C. difficile colonizes the intestines, releases toxins that destroy intestinal mucosa and cause inflammation, watery diarrhea.

Some common antibiotics likely to cause C. difficile infections are fluoroquinolones, cephalosporins, clindamycin and penicillins.

Emergence of a new strain

A new aggressive, highly resistant strain has emerged among people who haven't been hospitalized or taken antibiotics. The strain is responsible for several outbreaks of illness since 2000.

4 Making a Diagnosis

Making a diagnosis of C. difficile infection is done by performing several tests.

Doctors can suspect you for the infection if you develop diarrhea after antibiotic therapy or hospitalization and recommend you stool tests.

The bacterial toxins in your stool can be detected by:

  • Enzyme Immunoassay (EIA): It is a rapid and widely available test employed by many labs but is less sensitive and often gives false negative outcomes.
  • Polymerase Chain Reaction (PCR): It is a highly accurate, rapid test that detects C. difficile toxin B gene in stool sample. This test is not widely available but many laboratories are now adapting PCR and the availability is growing.
  • Cell Cytotoxicity Assay: This test detects the cytopathic effects of the C. difficile toxin on human cell culture. Though sensitive, it is more cumbersome to do and you have to wait for more than 24 to 48 hours for test results.

Some hospitals recommend the use of both EIA test and Cell Cytotoxicity Assay to produce accurate test results. In case you are not having diarrhea or watery stools, none of these tests are necessary.

Colon examination

In rare cases, examination of colon (flexible sigmoidoscopy or colonoscopy) can be carried out as confirmatory test for C. difficile infection. A flexible tube with a small camera on one end is inserted into your colon to detect inflamed area and pseudo-membranes.

Imaging tests

Advanced imaging tests like abdominal X-ray or a computerized tomography (CT) scan are employed to visualize possible complications such as thickening of the colon wall, expanding of the bowel, or more rarely, a mucosal perforation.

5 Treatment

Naturally, discontinuing antibiotic that triggered the infection is the first step of treatment process for C. Difficile infection. Treatment varies according to severity of the infection and include the following.


Antibiotics can treat diarrhea and other complications.

For mild to moderate infection:

Oral metronidazole (Flagyl). Common side effects are nausea and a bitter, metallic taste in your mouth. (Note: Metronidazole is not FDA approved for C. difficile infection, but has been shown to be effective in mild to moderate infection)

For more severe and recurrent cases:

Oral Vancomycin (Vancocin) or Fidaxomicin (Dificid). Study shows recurrence rate in Fidaxomicin group is lower than that in Vancomycin group. But Metronidazole and Vancomycin are more cost effective than Fidaxomicin. These drugs are commonly associated with abdominal pain and nausea.


Surgery is the last resort for people with severe pain, organ failure or inflammation of the lining of the abdominal wall.


Relapse of the infection is observed in about 20 percent of people with C. difficile, either due to new strain or failure to completely eradicate the bacteria in earlier infection. The rate of recurrence increases up to 65 percent after one or two recurrences.

The factors that aid risk for relapse are:

Treatment for recurrent disease may include:

  • Antibiotics: One or more courses of Vancomycin, given once every few days, a method known as a pulsed regimen.
  • Fecal microbiota transplant (FMT): Also called stool transplant, FMT involves placing donor’s stool in your colon to restore healthy bacteria. Study suggests FMT has a success rate of more than 90 percent for treating C. difficile infections but this emerging treatment approach has not yet been approved by FDA.
  • Probiotics: Microorganisms similar to those found in your gut may be used to restore normal intestinal flora. A yeast called Saccharomyces boulardii, in conjunction with antibiotics, is shown to prevent recurrence of C. difficile infections.

6 Prevention

Several preventive methods exist for C. difficile infection.

Avoid use of antibiotics for simple infections and for viral infections like the common cold.

Use antibiotics only when needed. Use the one with a narrow spectrum and for the shortest time possible.

Practice hygiene guidelines such as proper handwashing, use of sanitizers, and disinfectants to prevent the infection from spreading.

7 Lifestyle and Coping

Lifestyle modifications are necessary in order to cope with C. difficile infection.

Keep yourself hydrated with plenty of fluids.

Focus on good nutrition.

Consume starchy foods like potatoes, noodles, rice, wheat and oatmeal. Other good choices are saltine crackers, bananas, soup and boiled vegetables.

Note that you may experience difficulty digesting milk and milk-based products even after the diarrhea is over.

8 Risks and Complications

There are several risks and complications associated with C. difficile infection.

You may be at a greater risk for the infection if you are on antibiotic therapy (sometimes multiple antibiotics), taking broad-spectrum antibiotics, medications for hyperacidity for example proton pump inhibitors (PPIs) and staying in a health care facility. Some other risk factors are:

  • History of abdominal surgery or a gastrointestinal procedure.
  • Older age: People above 65 years are 10 times more likely to acquire the infection compared to younger people. Likewise, one incidence of infection increases chance of a second infection by 20 percent, and the risk increases further with every subsequent infection.


  • Dehydration: Severe diarrhea can lead to electrolyte imbalance and dangerously low blood pressure. Rarely, it may cause kidney failure.
  • Toxic megacolon: Inability to expel gas and stool results in swollen colon which if left untreated may rupture releasing bacteria from the colon to abdominal cavity. This is an emergency condition that requires immediate medical intervention. Rarely, extreme damage to intestinal mucosa can cause bowel perforation. Peritonitis, a life threatening condition, results when bacteria from perforated bowel reach the abdominal cavity.
  • Death: C. difficile infection irrespective of being mild or moderate can quickly progress to a fatal condition. So, it should be treated promptly.