What Is Clostridium Difficile (C. Difficile)?
Clostridium difficile, also known as C. difficile, or C. diff, is a bacterium which infects and can make humans ill, as well as other animals. Symptoms can range from diarrhea to serious and potentially fatal inflammation of the colon.
Elderly hospital patients, as well as those in long-term care facilities are most commonly affected by C. difficile – especially after or during the use of antibiotic drugs.

Clostridium difficile, often called C. difficile or "C. diff," is a bacterium that can cause symptoms ranging from diarrhea to life-threatening inflammation of the colon. Illness from C. difficile most commonly affects older adults in hospitals or in long term care facilities and typically occurs after use of antibiotic medications. In recent years, C. difficile infections have become more frequent, more severe and more difficult to treat. Each year, tens of thousands of people in the United States get sick from C. difficile, including some otherwise healthy people who aren't hospitalized or taking antibiotics. Mild illness caused by C. difficile may get better if you stop taking antibiotics. More severe symptoms require treatment with a different antibiotic.
C. difficile infection is gradually becoming more common, symptoms more severe and harder to treat. In North America, Europe, Australasia and many other parts of the world a significant number of people become ill from C. difficile – not only hospitalized patients taking antibiotics, but also otherwise healthy individuals.
Patients with mild symptoms may improve if they stop taking antibiotics. Those with severe symptoms need different antibiotic medications and sometimes further therapy.
C. difficile is present in the gut (intestinal tract) of approximately 3% of all adults and 66% of children. Healthy people are not usually affected by C. diff. However, some antibiotics may alter the balance of good bacteria in the gut, allowing C. diff to multiply and cause diarrhea, and possibly more serious illness.
The reason most cases of C. diff infection occur in healthcare environments is because of their link to antibiotic therapy – a significant number of hospitalized patients are on antibiotics. In industrialized countries approximately four-fifths of all C. diff cases occur in patients aged over 65 years.
The majority of patients with C. difficile infection recover completely without any long-term consequences. A small percentage, unfortunately, do have complications and some of them die.
In the UK there were 7% more cases of C. diff infection in 2006 compared to 2005. Experts say that improvements in testing technology and methods are partly responsible for the apparent increase. However, there is concern that the numbers are rising regardless.
Experts say that with good hygiene practices in healthcare environments, many C. diff infection cases can be prevented.
According to Medilexicon’s medical dictionary:
Clostridium difficile is “a bacterial species found in feces of humans and animals. It colonizes newborn infants, who are spared from toxin-induced diarrheal disease. Pathogenic for human beings, guinea pigs, and rabbits; frequent cause of colitis and diarrhea following antibiotic use. Found to be a cause of pseudomembranous colitis and associated with a number of intestinal diseases that are linked to antibiotic therapy; also the chief cause of nosocomial diarrhea.”
What are the signs and symptoms of Clostridium difficile?
A symptom is something the patient feels and reports, while a sign is something other people, including a doctor or a nurse may detect. For example, pain may be a symptom while a rash may be a sign.
The following signs and symptoms can occur as a result of C. difficile infection:
- Watery diarrhea (mild to severe)
- Bloody or blood stained stools
- Elevated body temperature
- Tummy ache (mild abdominal cramps and tenderness)
The above-mentioned symptoms are generally caused by inflammation of the lining of the large intestine (colitis). Although rare, C. difficile can also cause:
- Peritonitis – infection of the lining of the abdomen
- Septicemia – blood poisoning
- Perforation of the colon
Signs and symptoms in more severe cases may include:
- Dehydration
- Elevated body temperature
- Loss of appetite
- More severe abdominal cramping and pain
- Nausea
- Pus or blood in stool (feces)
- Watery diarrhea – the patient may go to the toilet ten or more times in a day.
- Weight loss
C. diff infection can be fatal; however, this is very rare. The risk of a life-threatening condition is higher among very elderly patients, as well as individuals with existing serious health conditions.
Most C. diff infection symptoms occur in patients who are taking antibiotic medications. It is not unusual for symptoms to appear ten weeks after antibiotic therapy has stopped.
What are the risk factors for Clostridium difficile?
In medicine, a risk factor is a condition, illness, situation or environment which raises the risk of developing a disease. For example, obese people are more likely to develop diabetes type 2 compared to people of normal weight. Therefore, obesity is a risk factor for diabetes type 2.
Most C. diff cases occur in hospitals or other health care environments – where germs may spread and a high proportion of people are taking antibiotics. Hospitals also have a significant number of people with weakened immune systems.
The following groups of people have a higher-than-normal risk of becoming ill from C. diff infection:
- Patients taking antibiotics. The risk is higher if they are broad-spectrum antibiotics – those aimed at a wide range of bacteria. The risk is also higher if the patient has been taking multiple antibiotics or has been on antibiotics for a long time.
- Patients who were recently on antibiotics.
- Individuals aged 65 years or older (ten times greater compared to a young person).
- Anybody who was recently hospitalized. The risk is higher if this was for an extended period.
- People who live in a long-term care facility or nursing home.
- Patients with a serious underlying medical condition or illness which weakens their immune system.
- People who have had an abdominal or gastrointestinal surgical intervention.
- Individuals with a colon disease.
- Patients who have had a previous infection with C. diff.
What are the causes of Clostridium difficile?
C. diff is a bacterium which does not need oxygen to live and reproduce – it is an anaerobic bacterium. Consequently, it generally survives well in our oxygen-poor large intestine.
C. diff can be found in soil, water, and human/animal feces. A small percentage of humans carry the bacteria in their intestines naturally. However, as far as we are concerned, C. diff is most commonly found in healthcare environments, such as hospitals, nursing homes and long-term health care facilities, where a significantly higher proportion of people carry the bacteria.
C. diff can spread from feces to food, and then surfaces and other objects. The spread is greater if people do not wash their hands regularly and properly. The bacterium produces spores which can resist harsh environments and can survive for months. The spores can also spread through the air – as may occur when making somebody’s bed. Unless rooms are thoroughly cleaned, the spores will survive for a long time.
Our intestines have millions of different types of bacteria, many of which protect us from infection. If a person takes antibiotics to treat an infection some of the helpful bacteria may be destroyed, giving C. diff an opportunity to gain a foothold and reproduce more rapidly – if the good bacteria numbers are low, the C. diff growth can rocket. The following antibiotics are linked to C. diff infections – fluoroquinolones, cephalosporins, clindamycin and penicillins.
As soon as C. diff bacteria have gained a foothold in a person’s body, they produce toxins that destroy cells and produce plaques (patches) of inflammatory cells and decaying cellular debris inside the colon.
There is a relatively new strain of C. diff which produces extremely potent toxins. This strain is resistant to many medications. Health experts are concerned that too many infections with this strain are occurring in people who have not been taking antibiotics and have not been in hospital.
If you have naturally-occurring C. diff in your gut, you cannot spread it to other people unless the bacteria start producing toxins.
Diagnosis of C. difficile
A GP (general practitioner, primary care physician), whose patient has diarrhea and was recently on antibiotics or in hospital will probably suspect C. diff infection. If so, one or more of the following tests may be ordered:
- Stool test – this may include an enzyme immunoassay, polymerase chain reaction, and tissue culture assay. The test will determine whether there are toxins produced by C. diff. Most laboratories tend to use the EIA (enzyme immunoassay) test – this test is fast, but results may occasionally be misleading (false-positive results). Hospitals tend to use the EIA test as well as a tissue culture assay for better accuracy.
- Flexible sigmoidoscopy – a flexible tube with a small camera at the end is inserted into the lower colon to seek out inflammation and pseudomembranes. This procedure may help confirm a diagnosis of C. diff infection.
- Imaging scans – if the doctor suspects there is a chance of a C. diff complication, he/she may order a CT (computerized tomography) scan. Detailed images of the colon will reveal any thickening of the colon’s wall; a common sign of pseudomembranous colitis.
What are the treatment options for C. diff?
If the patient has been taking an antibiotic during onset of symptoms the doctor will ask him/her to stop taking them. In mild cases this may be all that is needed. However, if symptoms are more intense, further treatment will be required.
- Antibiotics – standard treatment for C. diff infection is an antibiotic – a different one if the patient was on an antibiotic when symptoms started. If symptoms are moderate the doctor may prescribe metronidazole (Flagyl). For more severe symptoms vancomycin (Vancocin) may be used. In both cases, the aim is to stop the growth of C. diff, which allows good bacteria to reproduce in the intestine. These antibiotics may cause some side effects, including nausea and a bitter taste in the mouth. When taking metronidazole the patient must not consume alcohol.
- Probiotics – some types of bacteria and yeast help restore a healthy balance in the intestine. Saccharomyces boulardii, a natural yeast, together with antibiotics have been shown to prevent recurrences of C. diff infections.
- Surgery – if symptoms are severe, or if there is organ failure or inflammation of the lining of the abdominal wall, it may be necessary to surgically remove the diseased portion of the colon.
Treating recurrences of C. diff infections
About 25% of all patients infected with C. diff have recurrences (have it again). The infection may have occurred because the initial one was never completely eliminated, or a different strain of the bacteria has started to grow. Treatment may include:
- Antibiotics – various options may be used. For example, the patient may be given one or more courses of drugs, a long course of treatment, or an antibiotic once every couple of days.
- Probiotics – S. boulardii (type of yeast) together with an antibiotic.
- Stool transplant – donor stool is placed in the colon. The aim is to restore healthy intestinal bacteria. This type of treatment is rare.












