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Clostridioides difficile infection

Last updated: May 5, 2021

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Clostridioides difficile (C. difficile; formerly known as Clostridium difficile) is a gram-positive bacillus that may cause antibiotic-associated diarrhea. Rates of C. difficile infection are particularly high among hospitalized patients and residents in long-term care facilities because C. difficile spores are easily transmitted (fecal-oral route) and difficult to eradicate. The bacterium is resistant to multiple antibiotics, so colonization with C. difficile most commonly occurs following antibiotic treatment of other diseases. The resulting damage to the intestinal flora promotes infection, which may be accompanied by high fever, abdominal pain, and foul-smelling diarrhea. The most severe form of C. difficile infection is pseudomembranous colitis, which can lead to ileus, sepsis, and toxic megacolon. In most cases, however, colonization results in asymptomatic carriage. Diagnosis is usually made via detection of the C. difficile toxin, C. difficile glutamate dehydrogenase antigen, and/or corresponding genes in stool samples. C. difficile infection is treated with oral vancomycin or oral fidaxomicin. Following diagnosis, strict adherence to hygiene measures and patient isolation is essential, especially in hospitals and other healthcare settings.

  • ∼ 220,000 cases in hospitalized patients and ∼ 13,000 deaths per year in the US [1]
  • Individuals > 65 years old are at increased risk for the hospital-acquired infection. [2]
  • Patients affected by community-acquired infections are typically younger (average age 50 years). [3]

Epidemiological data refers to the US, unless otherwise specified.

The C. difficile strain must be toxigenic to cause the disease. Intestinal colonization by nontoxigenic strains will result in asymptomatic carriage.

C. difficile possesses a range of virulence factors, the most important of which are toxins A and B. [7][8]

Toxin A (enterotoxin)

Toxin B (cytotoxin)

  • Structure
    • Binding site at C-terminal domain
    • Translocation domain
    • Cysteine protease-containing domain
    • Catalytic domain
  • Mechanism of action: same as in toxin A, but can also cause pore formation within the endosomal membrane via insertion of the translocation domain → release of endosomal content into the cytosol cytopathic effect

Symptoms of C. difficile-associated diarrhea (CDAD) usually develop during antibiotic treatment or 2–10 days following its initiation; however, 25–40% of cases manifest as late as 10 weeks following treatment.

Clostridioides difficile Causes Difficult Diarrhea.


Patient history and clinical presentation are strong indicators for diagnosis of infection, which is then confirmed by identification of the pathogen's genes or corresponding toxins in the stool. Further diagnostics, such as blood tests or imaging, may be used to assess the severity of disease and/or the presence of complications.


  • Treatment with antibiotics in the last three months
  • Recent hospitalization

Stool tests [10]

Blood tests


Contrast-enhanced abdominal CT scan/x-ray to detect the following:


  • Not indicated if C. difficile is suspected based on clinical findings, laboratory tests, and/or response to empiric treatment
  • Perform cautiously (increased risk of perforation).
  • Findings
    • Erythematous and friable mucosa
    • Pseudomembranes, often only solitary findings; widespread lesions in severe cases (pseudomembranous colitis)

Disease severity [12]

General measures [9]

Medical therapy [10]

If clinical suspicion for CDAD is high, empiric antibiotic treatment may be initiated before laboratory confirmation of C. difficile. [9]

C. difficile infection is one of the rare indications for PO vancomycin!

Medical therapy in children [10]

Fecal microbiota transplantation (FMT) [10]

  • Indication: recurrent C. difficile infections in a patient who has not responded to at least two appropriate antibiotic regimens
  • Implementation: Sterile normal saline solution is added to donor stool and the mixture is blended to a smooth, liquid consistency.
  • Administration

We list the most important complications. The selection is not exhaustive.

  • Detection: C. difficile toxin stool test for at-risk patients with recent onset of diarrhea
  • Isolation
    • Single-bed room with designated bathroom facilities (up to 2 days after symptoms subside)
    • Cohort isolation is possible if control measures are implemented.
  • Control measures
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  2. Deshpande A, Pasupuleti V, Thota P, et al. Community-associated Clostridium difficile infection and antibiotics: a meta-analysis. J Antimicrob Chemother. 2013; 68 (9): p.1951-1961. doi: 10.1093/jac/dkt129 . | Open in Read by QxMD
  3. Khanna S, Gupta A. Community-acquired Clostridium difficile infection: an increasing public health threat. Infection and Drug Resistance. 2014 : p.63. doi: 10.2147/idr.s46780 . | Open in Read by QxMD
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  6. McDonald LC, Gerding DN, Johnson S, et al. Clinical practice guidelines for clostridium difficile infection in adults and children: 2017 update by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA). Clin Infect Dis. 2018; 66 (7): p.e1-e48. doi: 10.1093/cid/cix1085 . | Open in Read by QxMD
  7. Shen EP, Surawicz CM. Current Treatment Options for Severe Clostridium difficile-associated Disease. Gastroenterol Hepatol (N Y). 2008; 4 (2): p.134-139.
  8. Beck J, Nassal M. Hepatitis B virus replication. World J Gastroenterol. 2007; 13 (1): p.48-64.
  9. Antibiotic Resistance Threats in the United States, 2019 - Clostridioides difficile. Updated: November 14, 2019. Accessed: December 30, 2019.
  10. Jump RL. Clostridium difficile infection in older adults. Aging health. 2013; 9 (4): p.403-414. doi: 10.2217/ahe.13.37 . | Open in Read by QxMD
  11. Di Bella S, Ascenzi P, Siarakas S, Petrosillo N, di Masi A. Clostridium difficile Toxins A and B: Insights into Pathogenic Properties and Extraintestinal Effects. Toxins. 2016; 8 (5): p.134. doi: 10.3390/toxins8050134 . | Open in Read by QxMD
  12. Abt MC, McKenney PT, Pamer EG. Clostridium difficile colitis: pathogenesis and host defence. Nature Reviews Microbiology. 2016; 14 (10): p.609-620. doi: 10.1038/nrmicro.2016.108 . | Open in Read by QxMD
  13. Herold G. Internal Medicine. Herold G ; 2014