Clostridioides difficile infection (CDI): Frequently Asked Questions
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Clostridioides difficile (previously known as Clostridium difficile) infection (CDI) is a disease of the large intestine caused by toxins produced by the spore forming bacterium Clostridioides difficile. Around 5 to 10% of healthy people and many children under 2 years of age have these bacteria in the bowel without causing any symptoms. The bacteria are also found in animals such as pigs, horses and cattle.
The main source of transmission is patients with symptomatic infection. These people shed large numbers of C. difficile spores and bacteria in the faeces, resulting in widespread contamination of their skin, bed linen and nearby environmental surfaces. The spores are resistant to drying and the usual chemical cleaning agents, and can therefore remain in the environment for weeks or months. Spores can then be picked up on the hands of patients and healthcare workers.
Risk factors for CDI include
Since 2000, strains of C. difficile associated with outbreaks of infection (epidemic) and with more severe infection (hypervirulent) have been recognised. One strain appears to be easily and quickly transmitted from person-to-person and has been responsible for large outbreaks of infection in the United States of America (USA) and Europe. There are also increasing reports of cases in community settings with no history of recent antibiotic use.
Mild, self-limiting symptoms can include:
A serious form of the disease, known as pseudomembranous colitis (severe inflammation of the lining of the gut) has a high death rate if not recognised early and treated appropriately.
The trigger for symptoms is usually a disturbance of the normal bacteria in the gut during antibiotic treatment. This allows C. difficile to colonise (become established in) and multiply in the gut and produce toxins that attack the lining of the gut wall.
Diagnosis is made by laboratory testing of faeces from people with diarrhoea. The usual test for C. difficile toxin does not distinguish between strains. More specialised tests (PCR or polymerase chain reaction tests in a pathology laboratory) are required to detect the epidemic strains thought to be responsible for more severe disease.
(time between becoming infected and developing symptoms)
Average of 2 to 3 days
(time during which an infected person can infect others)
A person with diarrhoea from C. difficile infection is infectious while symptoms persist. C. difficile spores can survive in the environment for weeks or months.
CDI can be difficult to treat and has a high relapse rate. People with CDI are usually treated with antibiotics (metronidazole, or oral vancomycin in more severe disease and recurrent infections). There is no proof that probiotics (such as the natural bacteria in yoghurt) or faecal enemas are effective for treatment.
If a person with C. difficile infection is being managed at home:
If a person with C. difficile infection is being managed in a residential care facility or hospital, the Australian Guidelines for the Prevention and Control of Infection in Healthcare (2019) recommend:
While there is some controversy regarding the use of alcohol hand rubs for spore-forming organisms, recent consensus is that the use of gloves, as part of contact precautions, should prevent the contamination of hands with spores, and alcohol-based hand rubs can still be used after removal of the gloves. However, if there has been any unprotected exposure (for example, touching the patient or their environment without wearing gloves or direct soiling of the hands) then thorough washing with soap and water should be performed.