Clostridium difficile

Pronunciation

Klah-STRIH-dee-um dih-FIH-sih-lee

Clostridium difficile CDC

Other names

• C. difficile
• C. diff
• CDI (Clostridioides difficile infection)
• CDAD (Clostridioides difficile-associated disease)

Definition

A type of bacterium found in human and animal waste. Clostridium difficile is a common cause of diarrhea that occurs in hospitals. It can also cause diarrhea or other intestinal disorders in patients treated with antibiotics.

Risk factors

These infections mostly occur in:

Clostridium difficile colonies

• People 65 and older who take antibiotics and receive medical care
• People staying in hospitals and nursing homes for a long period of time
• People with weakened immune systems or previous infection with C. diff
• Recent antibiotic exposure (e.g., fluoroquinolones, third/fourth generation cephalosporins, clindamycin, carbapenems)
• Gastrointestinal surgery/manipulation
• Long length of stay in healthcare settings
• Any serious underlying illness
• Immunocompromising conditions
• Advanced age
• Other possible causes include Proton pump inhibitors, H2-blockers

Signs and symptoms

Symptoms might start within a few days or several weeks after you begin taking antibiotics.

Scanning electron micrograph of Clostridioides difficile bacteria from a stool sample.

Symptoms include:

• diarrhea: loose, watery stools for several days
• fever
• loss of appetite
• nausea
• abdominal pain/tenderness

C. diff can easily spread from person to person.

Incidence

C. diff is a major health threat worldwide. In 2017, there were an estimated 223,900 cases in hospitalized patients and 12,800 deaths in the United States, according to the CDC.

Diseases and conditions associated with C.diff

• pseudomembranous colitis (PMC)
• toxic megacolon
• perforations of the colon
• sepsis
• death (rarely)

Colonization versus infection

• Colonization is more common than CDI.
• The patient exhibits NO clinical symptoms (asymptomatic) but does test positive for the C. diff organism or its toxin.
• With infection, the patient exhibits clinical symptoms and tests positive for the C. diff organism or its toxin.

Colonic pseudomembranes

Diagnosis

A variety of tests are available to diagnose C.diff including the following:

• Molecular tests: FDA-approved PCR assays, which test for the gene encoding toxin B, are same-day tests that are highly sensitive and specific for the presence of a toxin-producing C. diff organism.
  • Molecular assays can be positive for C. diff in individuals who are asymptomatic.
  • When using multi-pathogen (multiplex) molecular methods, the results should be read with caution.
  • In addition, patients with other causes of diarrhea might be positive, which could lead to over-diagnosis and treatment.
• Antigen detection for C. diff: These are rapid tests (<1 hour) that detect the presence of C. diff antigen.
  • Because results of antigen testing alone are nonspecific, antigen assays have been employed in combination with tests for toxin detection, PCR, or toxigenic culture in two-step testing algorithms.ve results occur when specimens are not promptly tested or kept refrigerated until testing can be done.

Gram stain of C. difficile under 1000 magnification

• Toxin testing for C. diff:
  • Tissue culture cytotoxicity assay detects toxin B only.
  • This assay requires technical expertise to perform, is costly, and requires 24 to 48 hours for a final result.
  • It does provide specific and sensitive results for CDI.
  • While it served as a historical gold standard for diagnosing clinical significant disease caused by C. diff, it is recognized as less sensitive than PCR or toxigenic culture for detecting the organism in patients with diarrhea.
  • Enzyme immunoassay detects toxin A, toxin B, or both A and B. Due to concerns over toxin A-negative, B-positive strains causing disease, most laboratories employ a toxin B-only or A and B assay. Because these are same-day assays that are relatively inexpensive and easy to perform, they are popular with clinical laboratories. However, there are increasing concerns about their relative insensitivity (less than tissue culture cytotoxicity and much less than PCR or toxigenic culture).
  • C. diff toxin is very unstable. The toxin degrades at room temperature and might be undetectable within two hours after collection of a stool specimen. False-negative results occur when specimens are not promptly tested or kept refrigerated until testing can be done.

• Stool culture for C. diff: While this is the most sensitive test available, it is the one most often associated with false-positive results due to the presence of nontoxigenic C. diff strains.

Transmission

C. diff is shed in feces. Any surface, device, or material (such as commodes, bathtubs, and electronic rectal thermometers) that becomes contaminated with feces could serve as a reservoir for the C. diff spores. C. diff spores can also be transferred to patients mainly via the hands of healthcare personnel who have touched a contaminated surface or item.

Treatment

In about 20% of patients, CDI will resolve within two to three days of discontinuing the antibiotic to which the patient was previously exposed. The infection can usually be treated with an appropriate course (about 10 days) of antibiotics, including oral vancomycin or fidaxomicin. After treatment, repeat C. diff testing is not recommended if the patient’s symptoms have resolved, as patients often remain colonized.

Prevention

If a patient has had ≥ 3 stools in 24 hours:

• Order a C. diff test if other etiologies of diarrhea are ruled out.
• Isolate patients with C. diff immediately, even if you only suspect CDI.
• Wear gloves and gowns when treating patients with C. diff, even during short visits. Gloves are important because hand sanitizer doesn’t kill C. diff and handwashing might not be sufficient alone.
• In patient being evaluated for C. diff, reassess correctness of antibiotics.

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Clostridium difficile toxin B

Patient isolation

If the patient is positive for CDI:

• Continue isolation and contact precautions.
• Use antibiotics judiciously.
• Clean room surfaces thoroughly on a daily basis while treating a patient with C. diff and upon patient discharge or transfer using an EPA-approved spore-killing disinfectant.
• When a patient transfers, notify the new facility if the patient has or had a C. diff infection.
• CDIs can be prevented by using infection control recommendations and more careful antibiotic use.

Healthcare facilities - prevention

• Use antibiotics judiciously.
• Use contact precautions for patients with known or suspected CDI:
• Place these patients in private rooms. If private rooms are not available, they can be placed in rooms (cohorted) with other CDI patients.
• Use gloves when entering patients’ rooms and during patient care.
• Perform hand hygiene after removing gloves.
• Because alcohol does not kill C. diff spores, use of soap and water is more effective than alcohol-based hand rubs.
• Using gloves to prevent hand contamination remains the cornerstone for preventing C. diff transmission via the hands of healthcare personnel; any theoretical benefit from instituting soap and water must be balanced against the potential for decreased compliance resulting from a more complex hand hygiene message.
• Use gowns when entering patients’ rooms and during patient care.
• Dedicate or perform cleaning of any shared medical equipment.
• Continue these precautions until diarrhea ceases.

Making Health Care Safer-CDC Vital Signs

Contact precautions

• Because C. diff-infected patients continue to shed the organism for a number of days following cessation of diarrhea, some institutions routinely continue isolation and contact precautions for either several days beyond symptom resolution or until discharge, depending upon the type of setting and average length of stay.
• Implement an environmental cleaning and disinfection strategy.
• Ensure adequate cleaning and disinfection of environmental surfaces and reusable devices, especially items likely to be contaminated with feces and surfaces that are touched frequently.
• Ensure daily and terminal cleaning of patient rooms.
• Use an Environmental Protection Agency (EPA)-registered disinfectant with a sporicidal claim for environmental surface disinfection after cleaning in accordance with label instructions. (Note: Only hospital surface disinfectants listed on EPA’s List Kexternal icon are registered as effective against C. diff spores.)
• Follow the manufacturer’s instructions for disinfection of endoscopes and other devices.
• Recommended infection control practices in long-term care and home health settings are similar to those practices taken in traditional healthcare settings.

Disinfecting surfaces

Surfaces should be kept clean, and body substance spills should be managed promptly, as outlined in CDC’s Guidelines for Environmental Infection Control in Health-Care Facilities. Routine cleaning should be performed prior to disinfection. EPA-registered disinfectants with a sporicidal claim have been used with success for environmental surface disinfection in those patient-care areas where surveillance and epidemiology indicate ongoing transmission of C. diff.

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