Clostridioides Difficile Infection (CDI)

Clostridioides difficile Infection (CDI) or C. difficile is the major cause of infectious colitis and diarrhea in healthcare settings around the world. Infectious colitis is redness, swelling, and inflammation of the colon. (It was formerly known as Clostridium difficile; however, was renamed as after it was reclassified in 2016.)

How does Clostridioides Difficile Infections Spread?

CDI is often spread from one person to another from direct exposure to the bacteria. In the environment this is often due to personal hygiene. It spreads from the stool in one patient and ingested by the mouth of another. This type of spread is termed ‘fecal-oral’. Thorough hand washing with soap and water is important as hand sanitizers cannot kill CDI.

The C. difficile infection is able to grow within the gastrointestinal (GI) system. The bacteria and its spores resist heat, acid and antibiotics. For most people infected by CDI, symptoms will begin in 2-3 days post-exposure. In some cases, it may take greater than one week and up to 28 days to become symptomatic.

Types of Clostridioides Difficile Infections

  • Non-Severe CDI– The most common form of CDI seen is either mild colitis, or simple diarrhea. This diarrhea is watery and contains mucus but generally not blood. A sigmoidoscopy usually shows normal tissue in the colon. This test involves placing an endoscope through the anus and into the last part of the colon. An endoscope is a long flexible tube with a camera and light on the end. The camera allows your healthcare provider to see inside your GI tract during the test. With non-severe CDI, diarrhea may resolve by simply stopping the antibiotics. In others, a healthcare provider will prescribe antibiotic pills.
  • Severe CDI– Severe colitis is often present with a case of severe CDI or full-blown C. difficile-associated colitis. Severe CDI occurs when the patient has very bad diarrhea and possible dehydration as well as abnormal lab tests and/or Xrays. Sometimes, ‘plaques’ (pseudomembranes) can be seen with a camera during sigmoidoscopy in the lower colon. These plaques can also imply a severe case of CDI.
  • Fulminant CDI– This is the most serious type of CDI and is often seen with very serious complications. This can be life-threatening and occurs in 3% of patients. Most of those affected by this type are elderly and/or debilitated from other diseases. Patients with this form of the disease feel severe lower abdominal pain, diarrhea, high fever with chills, and rapid heartbeat.

What are the risk factors associated with CDI?

The main risk factor for CDI is exposure to the bacteria and use of antibiotics. Exposure most often occurs in a hospital setting. Antibiotics are given to treat a specific infection in a person. Consequently, these drugs also suppress the normal gut bacteria which is necessary for proper gut health. Suppressing healthy bacteria allows C. difficile to grow and colonize the large intestine. Even after stopping antibiotics, the risk for CDI remains for up to one month. Long-term treatment or taking multiple antibiotics at a time can further increase the risk for CDI.

Risk Factors which can lead to worse outcomes associated with CDI may include:

  • cancer chemotherapy
  • severe illness of any kind
  • stomach (gastric) acid suppression
  • small bowel obstruction
  • GI surgery
  • tube feedings
  • obesity
  • IBD
  • solid organ transplant
  • cirrhosis of the liver (live scarring and damage)
  • recent or soon to occur childbirth
  • chronic kidney disease

How is CDI Treated?

The primary treatment for C. difficile is an antibiotic that kills the bacteria itself. The choice of antibiotics depends on the severity and recurrence status of the infection. Supportive care, and close monitoring in a hospital setting is necessary for severe cases.

In some cases of recurrent Clostridioides Difficile Infection, Fecal Microbiota Transplant (FMT) may be recommended. With FMT, stool from a healthy donor is placed in the patient in an effort to add more of the ‘good’ bacteria. This can be highly effective in difficult cases. Surgery may be needed in a small subset of patients with toxic megacolon, colonic perforation, or necrotizing colitis.

How Likely am I to get CDI more than once?

CDI recurrence is the reappearance of symptoms within eight weeks after treatment ends after initial improvement. It is estimated that between 13 and 50% of patients with CDI will have at least one recurrence. This is often the result of a failure to kill all the spores, rather than a new infection.


Prevention strategies can help you and others from getting C.Difficile. These include (but are not limited to):

  • proper use of personal protective equipment (PPE).
  • Gloves and disposable gowns should be used by anyone in contact with the patient during the duration of symptoms.
  • Proper hand washing by the patient and anyone in contact with him/her.
  • Patients with CDI should be isolated in single rooms. These rooms should be cleaned with chlorine-based solutions.
  • Patients with CDI should avoid sharing toilets with other family members when possible.
  • Bathrooms should be sanitized with bleach-containing cleaners
More Information

This article is adapted from IFFGD’s Publication Clostridioides Difficile Factsheet #167  Updated 2021

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