C. difficile is a spore-forming, gram-positive anaerobic bacillus that produces two exotoxins: toxin A and toxin B. It is a common cause of antibiotic-associated diarrhea (AAD). It accounts for 15-25% of all episodes of AAD.
What are C. difficile-associated diseases?
They are diseases that result from C. difficile infections including:
- pseudomembranous colitis (PMC)
- toxic megacolon
- perforations of the colon
- death (rarely)
What are the main clinical symptoms of C. difficile-associated disease?
Clinical symptoms include:
- watery diarrhea
- loss of appetite
- abdominal pain/tenderness
Which patients are at increased risk for C. difficile-associated disease?
The risk for disease increases in patients with:
- antibiotic exposure
- gastrointestinal surgery/manipulation
- long length of stay in healthcare settings
- a serious underlying illness
- immunocompromising conditions
- advanced age
What is the difference between C. difficile colonization and C. difficile-associated disease?
C. difficile colonization
- patient exhibits NO clinical symptoms
- patient tests positive for C. difficile organism and/or its toxin
- more common than C. difficile-associated disease
C. difficile-associated disease
- patient exhibits clinical symptoms
- patient tests positive for the C. difficile organism and/or its toxin
Which laboratory tests are commonly used to diagnose C. difficile-associated disease?
- Stool culture for C. difficile: This is the most sensitive test available, but the one most often associated with false-positive results due to presence of non-toxigenic strains. Stool cultures for C. difficile also are labor intensive and require the appropriate culture environment to grow anaerobic microorganisms. Results are available within 48-96 hours of the test.
- Antigen detection for C. difficile: These are rapid tests (<1 hr) that detect the presence of C. difficile antigen by latex agglutination or immunochromatographicassays. They must be combined with toxin testing to verify diagnosis.
- Toxin testing for C. difficile*:
o Enzyme immunoassay detects toxin A, toxin B, or both A and B. It is a same-day assay but less sensitive than the tissue culture cytotoxicity assay.
o Tissue culture cytotoxicity assay detects toxin B only. This assay requires technical expertise to perform, is costly, and requires 24-48 hr for a final result. It does provide specific and sensitive results for C. difficile-associated disease.
* C. difficile toxin is very unstable. The toxin degrades at room temperature and may be undetectable within 2 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.
How is C. difficile transmitted?
C. difficile is shed in feces. Any surface, device, or material (e.g., commodes, bathing tubs, and electronic rectal thermometers) that becomes contaminated with feces may serve as a reservoir for the C. difficile spores. C. difficile spores are transferred to patients mainly via the hands of healthcare personnel who have touched a contaminated surface or item.
How is C. difficile-associated disease usually treated?
In 23% of patients, C. difficile-associated disease will resolve within 2-3 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 metronidazole or vancomycin (administered orally). After treatment, repeat C. difficile testing is not recommended if the patients’ symptoms have resolved, as patients may remain colonized.
How can C. difficile-associated disease be prevented in hospitals and other healthcare settings?
- Use antibiotics judiciously
- Use Contact Precautions: for patients with known or suspected C. difficile-associated disease:
o Place these patients in private rooms.If private rooms are not available, these patients can be placed in rooms (cohorted) with other patients with C. difficile-associated disease.
o Perform Hand Hygiene using either an alcohol-based hand rub or soap and water. Note: If your institution experiences an outbreak, consider using only soap and water for hand hygiene when caring for patients with C. difficile-associated disease; alcohol-based hand rubs may not be as effective against spore-forming bacteria.
o Use gloves when entering patients’ rooms and during patient care.
o Use gowns if soiling of clothes is likely.
o Dedicate equipment whenever possible.
o Continue these practices until diarrhea ceases.
- Implement an environmental cleaning and disinfection strategy:
o 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.
o Use an Environmental Protection Agency (EPA)-registered hypochlorite-based disinfectant for environmental surface disinfection after cleaning in accordance with label instructions; generic sources of hypochlorite (e.g., household chlorine bleach) also may be appropriately diluted and used. (Note: alcohol-based disinfectants are not effective against C. difficile and should not be used to disinfect environmental surfaces.)
o Follow the manufacturer’s instructions for disinfection of endoscopes and other devices.
o Infection control practices in long term care and home health settings are similar to those practices taken in traditional health-care settings.
What can I use to clean and disinfect surfaces and devices to help control C. difficile?
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.” Hospital cleaning products can be used for routine cleaning. Hypochlorite-based disinfectants have been used with some success for environmental surface disinfection in those patient-care areas where surveillance and epidemiology indicate ongoing transmission of C. difficile. Consult the aforementioned guidelines for use conditions for generic sources of hypochlorite-based products (e.g., household chlorine bleach) for disinfection of environmental surfaces.
Note: EPA-registered hospital disinfectants are recommended for general use whenever possible in patient-care areas. At present there are no EPA-registered products with specific claims for inactivating C. difficile spores, but there are a number of registered products that contain hypochlorite. If an EPA-registered proprietary hypochlorite product is used, consult the label instructions for proper and safe use conditions.
Where can I get more information?
The Centers for Disease Control and Prevention also has General Information about C. difficile and more information about Gastrointestinal Infections in Heathcare Settings.
Additional Scientific References:
* Boone N, Eagan JA, Gillern P, Armstrong D, Sepkowitz KA. Evaluation of an interdisciplinary re-isolation policy for patients with previous Clostridium difficile diarrhea. Am J Infect Control 1998;26:584–7.
* CDC. Guidelines for environmental infection control in health-care facilities. MMWR 2003;52 (RR10):1–42. Also available at: http://www.cdc.gov/ncidod/hip/enviro/guide.htm.
* CDC. Guidelines for hand hygiene in health-care settings. MMWR 2002;51 (RR16):1–45.
* Johnson S, Gerding DN. Clostridium difficile-associated diarrhea. Clin Infect Dis 1998;26:1027–36.
* Simor AE, Bradley SF, Strausbaugh LJ, Crossley K, Nicolle LE. SHEA Position Paper: Clostridium difficile in long-term-care facilities for the elderly. Infect Control Hosp Epidemiol 2002;23:696–703.
* Gerding DN, Johnson S, Peterson LR, Mulligan ME, Silva J. SHEA Position Paper:Clostridium difficile-associated diarrhea and colitis. Infect Control Hosp Epidemiol 1995;16:459–77.
* Poutanen, Simor AD. Clostridium difficile-associated diarrhea in adults. CMAJ 2004;171(1):51-8.