Clostridioides difficile infection (CDI)

Clostridioides difficile (previously known as  Clostridium difficile) is a spore-forming anerobic Gram positive bacillus (bacterium) that is responsible for diarrhoeal illness associated with the consumption of antibiotics.

It is common in the natural environment and in healthcare environments and in the gastrointestinal tract of some animals, healthy adults and young children.

Clostridioides difficile (C.difficile) is the most common cause of health care-associated and antibiotic-associated diarrhoea.

The severity of illness can range from a mild diarrhoea of variable duration to a severe inflammation of the colon (colitis), toxic megacolon and necrosis of the large bowel. Severe cases are associated with a significant morbidity and mortality.

Mode of transmission

C. difficile is transmitted from person to person by the faeco-oral route. 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 and be transmitted to others.

Screening and alerting recommendations for C diff

Diagnosis of CDI is made by laboratory detection of the toxin produced by C. difficile in the faeces of people with relevant symptoms and a recent history of taking antibiotics or immunosuppressed. Identifying and isolating patients who are colonised or infected with Clostridioides difficile and undertaking necessary infection control precautions.


The prevention of cross-infection with C. difficile involves the use of Standard and Transmission Based Precautions including:

Further information

For further information about Clostridiodes difficile see the Clostridiodes difficile infection (CDI): Fact sheet for Healthcare Professionals (PDF 432KB) or contact SA Health's Infection Control Service.