What is C. diff. (Clostridium difficile)?

Clostridium difficile is gram-positive, anaerobic, and a spore, rod/spindle-shape,
a common bacterium of the human intestine in 2 – 5%. C diff. becomes a serious gastrointestinal infection when individuals have been exposed to antibiotic therapy, and/or have experienced a long-term hospitalization, and/or have had an extended stay in a long-term care facility. However; the risk of acquiring a C diff. infection (CDI) has increased as it is in the community and found in outpatient settings. There are significant risk factors in patients who are immunosuppressant, ones who have been on antibiotic therapy, and the elderly population.

How do Antibiotics cause C diff.? The antibiotics cause a disruption in the normal intestinal flora which leads to an over growth of C difficile bacteria in the colon. The leading antibiotics known to disrupt the normal intestinal flora, yet not limited to, are Ampicillin, Amoxicillin, Cephalosporins, Clindamycin, and the broad spectrum antibiotics.

Strain Types and Changing Epidemiology

Excerpts from the Clinical Practice Guidelines : IDSA


The emergence of the virulent, epidemic ribotype 027 strain was associated with increased incidence, severity, and mortality during the mid-2000s and resulted in outbreaks across North America [36, 48, 49], England [50, 51], parts of continental Europe [52, 53], and Asia [54]. The recent isolates of the 027 strain are more highly resistant to fluoroquinolones compared to historic strains of the same type [48]. This, coupled with increasing use of the fluoroquinolones worldwide likely promoted dissemination of a once uncommon strain [48].

Consistent with the presence of one or more molecular markers responsible for increased virulence, patients infected with the 027 epidemic strain in Montreal were shown to have more-severe disease than patients infected with other strains [36]. In a later Canadian multicenter study of hospitalized patients, the 027 strain was predominant among patients with CDI, whereas other strains were more common among asymptomatically colonized patients [46]. Similarly, in a sample of isolates and patient information collected from 10 CDC EIP sites between 2009 and 2011, ribotype 027 was the most prevalent strain (28.4%) and was associated with more severe disease, severe outcomes, and death than other strains, controlling for patient risk factors, healthcare exposure, and antibiotic use [55].

Since the emergence and spread of 027, recent data from Europe suggest that the prevalence of this strain is decreasing. England has seen a dramatic decrease in 027 prevalence since the establishment of a nationwide ribotyping network in 2007 [56]. Ribotype 027 decreased significantly between 2007 and 2010, dropping from 55% prevalence to 21%, coincident with significant decreases in reported CDI incidence and related mortality. The decrease in 027 prevalence was likely driven by significant reductions in fluoroquinolone use during this time period [56], although increase in awareness and improved infection control may also have impacted CDI incidence.

Continued molecular typing will enable detection of emerging C. difficile strains with novel virulence factors, risk factors, and antibiotic resistance patterns. For example, evidence of emergence of a virulent strain, ribotype 078, has been reported from the Netherlands [57]. The prevalence of ribotype 078 increased between 2005 and 2008 and was associated with similar severity compared to CDI cases due to ribotype 027, but was associated with a younger population and more CA CDI. There was also a high degree of genetic relatedness between 078 isolates found in humans and pigs, an association also noted in the United States [58].


What is the role of antibiotic stewardship in controlling C.diff. infection rates?

  1. Minimize the frequency and duration of high-risk antibiotic therapy and the number of antibiotic agents prescribed, to reduce CDI risk (strong recommendation, moderate quality of evidence).
  2. Implement an antibiotic stewardship program (good practice recommendation).
  3. Antibiotics to be targeted should be based on the local epidemiology and the C. difficile strains present. Restriction of fluoroquinolones, clindamycin, and cephalosporins (except for surgical antibiotic prophylaxis) should be considered (strong recommendation, moderate quality of evidence).

What is the role of proton pump inhibitor restriction in controlling CDI rates?

  1. Although there is an epidemiologic association between proton pump inhibitor (PPI) use and CDI, and unnecessary PPIs should always be discontinued, there is insufficient evidence for discontinuation of PPIs as a measure for preventing CDI (no recommendation).

What is the role of probiotics in primary prevention of CDI?

  1. There are insufficient data at this time to recommend administration of probiotics for primary prevention of CDI outside of clinical trials (no recommendation).

Since November 2012 the CDC shared a public announcement regarding antibiotic use: Colds and many ear and sinus infections are caused by viruses, not bacteria. Taking antibiotics to treat a “virus” can make those drugs less effective when you and your family really need them. Limiting the usage of antibiotics will also help limit new cases of CDI.
*Always discuss the symptoms and medications with the treating Physician.


What is the minimal surveillance recommendation for institutions with limited resources?

  1. At a minimum, conduct surveillance for HO-CDI in all inpatient healthcare facilities to detect elevated rates or outbreaks of CDI within the facility (weak recommendation, low quality of evidence).

What is the best way to express CDI incidence and rates?

  1. Express the rate of HO-CDI as the number of cases per 10000 patient-days. Express the CO-HCFA prevalence rate as the number of cases per 1000 patient admissions (good practice recommendation).

How should CDI surveillance be approached in settings of high endemic rates or outbreaks?

  1. Stratify data by patient location to target control measures when CDI incidence is above national and/or facility reduction goals or if an outbreak is noted (weak recommendation, low quality of evidence).


What is the recommended CDI surveillance strategy for pediatric institutions?

  1. Use the same standardized case definitions (HO, CO-HCFA, CA) and rate expression (cases per 10000 patient-days for HO, cases per 1000 patient admissions for CO-HCFA) in pediatric patients as for adults (good practice recommendation).
  2. Conduct surveillance for HO-CDI for inpatient pediatric facilities but do not include cases <2 years of age (weak recommendation, low quality of evidence).
  3. Consider surveillance for CA-CDI to detect trends in the community (weak recommendation, low quality of evidence).

2 thoughts on “What is C. diff. (Clostridium difficile)?

  1. Janette Simon

    I need an education tool, like an easy-to-read brochure, to give to patients and families on c. diff. can you direct us?


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