The bacterium Clostridioides difficile is the most common cause of healthcare-associated infectious diarrhoea and has the potential to cause life-threatening illness (SA Health 2024a).
Alarmingly, one in five patients who experience Clostridioides difficile infection will be re-infected within 21 days of their initial illness (ACSQHC 2021).
There’s one key factor increasing the risk of CDI: misuse and overuse of antimicrobials (ACSQHC 2021).
So, how can this be combatted?
Clostridioides difficile, also known as C. difficile or C. diff, is an anaerobic, gram-positive, spore-forming bacterium (Mada & Alam 2024).
Previously, C. diff was referred to as Clostridium difficile before being reclassified to a new genus in 2016 (The Lancet Infectious Diseases 2019).
C. diff bacteria are able to survive for long periods of time outside of the body by forming spores, allowing them to enter a dormant state that is highly resistant to the environment and easy to transmit (Basta & Annamaraju 2023; Mayo Clinic 2023).
For this reason, dormant C. diff can be found anywhere in the environment, including:
(Mayo Clinic 2023)
Once ingested, the bacteria reactivate inside the digestive system (Mayo Clinic 2023).
In healthy adults with normal immune function, C. diff does not cause disease (Mada & Alam 2024). In fact, about 5 to 10% of healthy people and 15 to 70% of neonates are carrying C. diff in their gut at any given time without experiencing symptoms (SA Health 2024b; VIC DoH 2024).
Clostridioides difficile infection (CDI) occurs when the microbial flora in the large intestine is altered through the use of antibiotics (Mada & Alam 2024). This change allows the C. diff to multiply and produce toxins (SA Health 2024b).
People with symptomatic infection shed large numbers of C. diff in their faeces, contaminating their skin, bed linen and nearby surfaces with bacteria and spores. The spores, which are highly resistant to typical cleaning agents, can remain dormant in the environment for weeks or months (SA Health 2024b).
These spores can then be picked up by healthcare workers caring for symptomatic patients (typically via the hands), and transmitted to other vulnerable patients (NHMRC 2020).
C. diff is transmitted from one person to another via the faecal-oral route (Mada & Alam 2024).
People are considered non-infectious once they have not experienced diarrhoea for at least 48 hours, however, C. diff spores they shed may remain in the environment and can still be spread (NHMRC 2020).
Those at the highest risk of CDI are people receiving prolonged treatment at a healthcare facility, especially if they are sharing bathrooms or toilets with people colonised with C. diff (NHMRC 2020).
Factors that further increase the risk include:
(NHMRC 2020; SA Health 2024b)
Symptoms typically occur two to three days after infection (SA Health 2024b).
CDI usually presents as colitis (infection of the colon/large intestine) (VIC DoH 2024), with symptoms including:
(SA Health 2024b; Mada & Alam 2024; NHMRC 2020)
In severe cases, the patient might develop pseudomembranous colitis - a serious illness where the lining of the gut becomes inflamed, causing the patient to present severely unwell with abdominal distension and pain. If not detected and treated early, pseudomembranous colitis is potentially fatal (SA Health 2024b; VIC DoH 2024).
CDI is diagnosed via laboratory testing of stool samples (SA Health 2024b).
First-line treatment usually includes ceasing the antibiotic currently being taken (if possible) and targeted antibiotic therapy (e.g. oral metronidazole or vancomycin) according to Therapeutic Guidelines (VIC DoH 2024; Queensland Health 2024).
Hospitalised patients should be isolated in a single room with a separate bathroom until 48 hours after their diarrhoea has resolved (VIC DoH 2024; Queensland Health 2024).
Relapse of CDI is common (SA Health 2024b). Alternative treatments may be required for recurrent infection (Queensland Health 2024).
If the patient develops a fulminant infection, which is characterised by hypotension or shock, ileus, or megacolon (enlarged colon), emergency surgery may be considered (Zuckerbraun 2025).
The most crucial way to reduce the prevalence of CDI is to avoid the unnecessary use of antibiotics, especially those that commonly precede CDI (SA Health 2024b). These include:
(Queensland Health 2024; VIC DoH 2024)
However, all types of antibiotics can increase vulnerability to CDI (Queensland Health 2024).
It’s essential that when antibiotics are required, the narrowest-spectrum medicine is used for the shortest period of time possible (VIC DoH 2024).
In healthcare facilities where a person with CDI is being treated, the following measures should be taken to reduce the risk of spreading C. diff:
(SA Health 2024b; NHMRC 2020)
Question 1 of 3
What is the likelihood of Clostridioides difficile infection relapse occurring within three weeks of the original infection?
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