An Overview of C. Diff

A highly contagious "bad" gut bacteria that can cause watery diarrhea

Clostridium difficile bacteria.

Clostridioides difficile, often called C. diff, is a bacteria present normally in small amounts in the human gastrointestinal (GI) tract. When the balance of bacteria in your GI tract becomes disturbed (most commonly from taking an antibiotic), C. diff can take over, flourish, and release toxins that cause diarrhea and abdominal cramping.

The diagnosis of a C. diff infection is suspected from a person's symptoms (e.g., watery diarrhea multiple times a day) and potential triggers (e.g., antibiotic use or recent hospitalization).

Treatment involves taking antibiotics and ample fluid intake. Rarely, in life-threatening cases, surgery to remove the colon may be warranted.

According to the Centers for Disease Control and Prevention, C. diff is estimated to cause nearly half a million illnesses in the United States each year.


C. diff infections may develop when an imbalance in the gut flora occurs, allowing the bacteria C. diff to grow and release toxins that irritate the intestinal lining.

There are several factors that can throw off the balance of bacteria in the human gut.

The most typical and common factor associated with C. diff infections is taking a broad-spectrum antibiotic, which targets and kills both "good" and "bad" bacteria in the intestines because it cannot distinguish one from the other.

A C. diff infection may occur during or after taking an antibiotic, and the infection risk increases the greater the number of doses, and the longer the time the antibiotic is taken.

Examples of antibiotics associated with the highest risk of developing a C. diff infection include:

  • Cleocin (clindamycin)
  • Fluoroquinolones, such as Cipro (ciprofloxacin)
  • Carbapenem-type drugs, such as Primaxin (imipenem)

Another factor associated with C. diff infection is recent hospitalization. C. diff is shed in feces and easily spreads within the environment it is found in, which is often hospitals.

In fact, C. diff bacteria are often found on hospital bedrails, bed linens, commodes, the bathroom door handle or fixture, floors, electronic rectal thermometers, and other medical equipment.

Therefore, people who have been in the hospital or other long-term care facilities (e.g., nursing home) are more likely to be exposed to and infected with C. diff.

Besides antibiotic use and recent hospitalization, other factors associated with a C. diff infection include:


The cardinal symptom of a C. diff infection is diarrhea, specifically loose, watery stools that occur frequently throughout the day.

Other symptoms may include:

  • Abdominal cramping
  • Fever
  • Loss of appetite
  • Nausea

Complications of a C. diff infection are rare but may include the following:

Keep in Mind

It's fairly common to develop diarrhea while (or after) taking an antibiotic, and in most cases, the culprit is not C. diff.

That said, if you are experiencing significant diarrhea, especially if one of the other above symptoms is present, be sure to seek medical attention.


A C. diff infection is suspected based on a person's medical history and confirmed with a laboratory test.

Medical History

In general, it's often a patient's medical history that prompts a doctor to suspect a C. diff infection. For instance, a patient may report diarrhea with or without abdominal cramping while in the hospital and/or during or after a course of antibiotics.

Laboratory Test

While there are a few different tests available, the diagnosis of C. diff is usually confirmed by a positive stool test for one or both toxins produced by C. diff (called toxin A and toxin B) or for the gene that encodes toxin B.


The treatment of an infection with C. diff involves the following steps: 

  • Stopping the inciting antibiotic (if present and possible)
  • Isolating the patient with C.diff and implementing contact precautions (in the hospital): This includes wearing gloves (hand sanitizer does not kill C. diff) and gowns; of note, these precautions are done immediately upon suspicion of a C.diff infection, even prior to a laboratory test confirming the diagnosis
  • Hydration and electrolyte replacement: This may be done orally (by mouth) at home or in more severe cases, intravenously (through the vein) in the hospital
  • Antibiotic Administration: Even though C. diff can be the result of antibiotic exposure, it is treated (ironically) using antibiotics. The antibiotics of choice for most patients are either Flagyl (metronidazole), vancomycin, or Dificid (fidaxomicin).

Infection Severity

The severity of a C. diff infection varies from person to person. While most people who contract C. diff in the hospital will be treated successfully, for those who are immunocompromised, it can be life-threatening. In severe cases, removal of the colon (called a colectomy) may even be considered, along with very close monitoring in a hospital.

Infection Recurrence

It's important to note that C. diff can reoccur—about one in five people with C. diff will get it again. For first-time recurrences of C. diff, an antibiotic regimen with oral vancomycin or oral fidaxomicin is recommended. For second or further recurrences, a fecal microbiota transplantation (FMT) may be recommended.

With a fecal microbiota transplantation, stool from a healthy donor is delivered by colonoscopy or oral capsules into the gastrointestinal tract of someone who gets recurrent C. diff infections.


In order to prevent the spread of C. diff, which is highly contagious, here are some precautions to take if you're around someone who's infected with C. diff, or if you're spending time in an environment where C. diff is known to proliferate, like a hospital or nursing home.

  • Scrub your hands and fingers thoroughly with soap and warm water for 30 to 40 seconds (the time it takes to sing the Happy Birthday song two times) every time you use the bathroom and prior to eating
  • Wash linens, clothing (especially underwear), and towels that an infected person has used in hot water with both laundry soap and chlorine bleach. 
  • Wipe down all hard surfaces, from light switch plates to toilet flushers and seats, oven and refrigerator handles, doorknobs, and computer touchpads with a bleach-based cleaning product (mix one part bleach to 10 parts water)
  • Make sure that healthcare providers are using certain precautions (wearing gowns and gloves) if they are caring for a person infected with C. diff

A Word From Verywell

If you are hospitalized and/or are taking an antibiotic or finished a course of antibiotics within the last month and begin to suffer from significant diarrhea, be sure to notify your doctor, as you may need testing for C. diff.

Also, if you are diagnosed with a C. diff infection, try not to fret. You can be treated for it and with routine and thorough handwashing, you can prevent the spread to others.

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Article Sources

  1. Centers for Disease Control and Prevention. (2018). Clostridioides difficile (C. diff).

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  5. Peng Z et al. Advances in the diagnosis and treatment of Clostridium difficile infections. Emerg Microbes Infect. 2018; 7:15. doi:10.1038/s41426-017-0019-4

  6. Kao D et al. Effect of Oral Capsule- vs Colonoscopy-Delivered Fecal Microbiota Transplantation on Recurrent Clostridium difficile Infection: A Randomized Clinical Trial. JAMA 2017 Jov 28;318(20):1985-93. doi:10.1001/jama.2017.17077

  7. Centers for Disease Control and Prevention. (2019). Prevent the Spread of C. diff

Additional Reading