Background

What is Clostridioides difficile?

Clostridioides difficile / C. difficile (previously called Clostridium difficile) is the name of a bacteria that that can live harmlessly in the bowel along with other types of bacteria. (NEED A REFERENCE) When the bacterium is present but does not cause symptoms, this is referred to as colonisation. However, when the balance of bacteria in the bowel changes (e.g. following treatment with certain antibiotics), C. difficile can grow in numbers and produce toxins. These toxins can cause disease ranging from mild diarrhoea to life-threatening conditions, such as pseudomembranous colitis and sepsis (C. difficile associated disease or CDI). While most people who develop CDI experience only mild symptoms, some, including those with underlying illness and older adults, are more at risk of severe illness. 

With respect to transmission, C. difficile bacteria and their spores can spread from person to person via the faecal-oral route, direct contact or touching a contaminated surface and then touching your mouth. Indirect contact, such as touching contaminated objects or surfaces like cloths, door handles, utensils, and contaminated medical equipment.

C. difficile can cause outbreaks in health and social care settings (including care homes). Appropriate use of antibiotics and effective infection prevention and control (IPC) measures can be used to prevent CDI. Early identification of the signs of infection, appropriate laboratory testing, diagnosis and treatment can help to reduce the burden of disease and prevent outbreaks in healthcare settings. C. difficile is a leading cause of healthcare associated infections that requires effective public health measures to prevent and control.

Risk Factors

Risk factors for developing CDI include:   

• Current or recent (within last 3 months) use of antimicrobial agents (cephalosporins, broad spectrum penicillins, fluoroquinolones and clindamycin). 

• Increased age (> 65 years old) 

• Previous diagnosis with CDI 

• A recent or prolonged hospital stay 

• Serious underlying diseases or comorbidities 

• Surgical procedures (in particular bowel procedures) 

• Immunosuppression 

• Use of proton pump inhibitors (PPI) or H2 antagonists (drugs which reduce the production of stomach acid)[@publichealthscotlandGuidancePreventionControl2024] 

• Care homes and nursing home residents [@haranHighPrevalenceClostridioides2021] 

• Enteral Tube Feeding /people who are fed by a method that bypasses some of the digestive processes in the body. (NEED A REFERENCE)

Signs and symptoms

The common symptoms of CDI are:  

• Diarrhoea  

• Loss of appetite  

• High temperature  

• A stomach pain  

• Feeling sick [@nhsClostridioidesDifficileDiff2025] 

Complications of CDI include dehydration, inflammation of the colon (severe colitis and pseudomembranous colitis), extreme swelling of the bowel (toxic megacolon), bowel perforation and blood stream infection (bacteremia and sepsis). [@ukhealthsecurityagencyClostridioidesDifficileInfection2024]

Diagnosis of CDI

When clinically suspected, CDI diagnosis is confirmed through a set of laboratory tests on a type 6/7 stool sample. One test detects the presence of C. difficile bacteria, which may be due to colonisation rather than active infection and illness. Another test looks for the toxins that cause illness, suggestive of active infection. Further laboratory tests can be carried out on the sample if the initial results are unclear. Final diagnosis is based on consideration of these test results alongside the person’s symptoms and medical history. Clinicians can consult with the consultant microbiologist for diagnosis and treatment advice and support for cases in both hospital or community settings.  

Treatment of CDI

Treatment of CDI should start when a patient has symptoms of CDI. Those without symptoms of active infection are not recommended for treatment.[@nationalinstituteforhealthandcareexcellenceOverviewClostridioidesDifficile2021] The main principle of treatment is to give targeted antibiotics that treat CDI (thereby preventing complications) while preserving healthy gut bacteria. Patients are assessed for dehydration and may need fluids or supportive care.  

Nice guidelines should be referred to for treatment recommendations for CDI and if required further advice can be sought from the consultant microbiologist. Advice in in regard to adjustments in specific populations e.g. people with hepatic impairment, renal impairment, pregnancy or breastfeeding can be found in BNF. 

What the data shows

Mortality

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Cases

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Hospital-acquired vs. community-acquired C. difficile infection

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C. difficile trends by subgroup

Age & Sex: Rates of infection in most age groups across both males and females have reduced between 2007/08 to 2024/25 at the national level. Since 2020/21, there have been increases across most age-sex categories. This is particularly the case in the 85 and over cohort which has increased consecutively up to 2024/2025.[@ukhealthsecurityagencyAnnualEpidemiologicalCommentary2025] 

Ethnicity: Nationally, rates of infection in 2024/25 were highest in the White ethnic group, followed by Black and Asian ethnicities. In 2024/25, all ethnic groups experienced their highest age-standardised rates of C. difficile since recording for ethnicity began in 2017/2018.[@ukhealthsecurityagencyAnnualEpidemiologicalCommentary2025] 

Deprivation: Nationally, crude and age-standardised rates of C. difficile infection in the most deprived quintile are significantly higher than the equivalent rates in the least deprived quintile. [@ukhealthsecurityagencyAnnualEpidemiologicalCommentary2025] 

Prevention

Five main factors have been identified as necessary for the effective prevention and control of CDI. These include: 

• Prudent antimicrobial prescribing and monitoring in all healthcare settings [@ukhealthsecurityagencyClostridioidesDifficileInfection2022]  

• Environmental decontamination in areas with patients / residents with CDI using chlorine-based disinfectants or other sporicidal products and deep-clean of rooms after patients / residents have recovered / have been discharged from healthcare setting.[@departmentofhealthHighImpactIntervention2007] 

• Effective hand hygiene using soap and water and monitoring for hand hygiene compliance in healthcare settings.[@departmentofhealthHighImpactIntervention2007] 

• Isolation of individuals with known or suspected CDI a single room with ensuite toilet facilities / a dedicated commode.[@departmentofhealthHighImpactIntervention2007] 

• Use of aprons and gloves when caring for a patient / resident with CDI / cleaning the environment.[@departmentofhealthHighImpactIntervention2007]  

Conclusion

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C. difficile infection is a common healthcare associated cause of gastro-intestinal disease, ranging from mild diarrhoea to life-threatening conditions. Antibiotic usage, older age (over 65), hospital admission, residence in a care or nursing home, and long-standing conditions are the recognised risk factors. 

While mortality of C. difficile has fallen, cases have increased across both healthcare and community settings. Some of this increase may relate to better detection and reporting, and structural trends such as an ageing population and higher health and care use. Nonetheless as a preventable infection it is important for health and care settings to remain vigilant of steps they can take to reduce infections - through better antibiotic stewardship, infection prevention and control measures, an understanding of risk factors, and prompt detection, diagnosis and management.