Diagnosis

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.

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. 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.

Colon examination

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.

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.

Treatment

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.

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 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.

Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this disease.

Lifestyle and home remedies

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.

C. difficile infection care at Mayo Clinic

June 18, 2016
References
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