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.[1] 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 (which can happen following the use of antibiotic), 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. The clinical condition is referred to as ‘C. difficile infection’ 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. It can also spread through 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 infection, and so requires effective public health measures to prevent and control.
Risk Factors
Risk factors for developing CDI [2] 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)
- Care homes and nursing home residents [3]
- Enteral Tube Feeding /people who are fed by a method that bypasses some of the digestive processes in the body [4]
Signs and symptoms
The common symptoms of CDI [5] are:
- Diarrhoea
- Loss of appetite
- High temperature
- A stomach pain
- Feeling sick
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 (bacteraemia and sepsis). [6]
Diagnosis of CDI
When clinically suspected, CDI diagnosis is confirmed through a set of laboratory tests on a type 6 and 7 stool sample as in the Bristol Stool Chart. 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.[7] 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 regard to adjustments in specific populations (such as people with hepatic impairment, renal impairment, pregnancy or breastfeeding) can be found in The British National Formulary (BNF).
What the data shows
Mortality
Mortality data linked to CDI is sourced from the HCAI Data Capture System. An individual is recorded if they had a positive CDI test within the 30 days prior to their death. The metric 30 day all-cause fatality estimates present risk of death following an infection, however it does not necessarily provide insight into attributable mortality (the specific cause of death).
The mortality linked to CDI dropped substantially between 2007 and 2012 due to a better understanding of the infection and national policies introduced around antibiotic stewardship and infection control. Between then and 2022/23, rates across England have remained relatively stable at an average of 3.7 per 100,000. The rate observed in the London NHS region has been consistently lower than the national value, averaging at 2.6 per 100,000 population across the same period. There was an increase in rate observed in London from2.03 to 2.3 per 100,000 between 2021/22 and 2022/23.
Similarly to mortality rate, the case fatality rate linked to CDI declined substantively between 2007 and 2012, and has been steadily decreasing since. The case fatality rate in London was 24.9% in 2007/08, and has decreased to 12.1% in 2022/23. Case fatality rates in London have been lower than values observed nationally since 2015/16, with the national rate at 13.8% in 2022/23. Both the London NHS Region and England experienced an increase during the COVID-19 pandemic.
Cases
C. difficile infections are monitored by the UK Health Security Agency. The following figures account for all positive tests in patients above the age of 2.
Overall, the rate of CDI cases in England increased from 22.2 per 100,000 population to 33.3 per 100,000 between 2020/ 21 and 2024/ 25, a growth of 49.8%. This increase has been observed across all age groups and in both community acquired and hospital-acquired cases of CDI.
The London NHS region has not experienced the same extent of increase as England during that time. The infection rate in the London NHS region in 2024/25 was 18.8 per 100,000 population. North Central London ICB observed a peak infection rate at 24.7 per 100,000 in 2022/23. After falling below 20 per 100,000 in 2023/24, the rate again increased to 23.1 in 2024/25.
Hospital-acquired vs. community-acquired CDI
Nationally, there have been increases in the rate of C. difficile infections in hospital-onset healthcare-associated (HOHA), community-onset healthcare-associated (COHA) and community-onset community-associated (COCA) categories. The greatest increase has been observed in HOHA cases, with a 73.1% increase between financial year 2018/19 and 2024/25.[8]
Community-onset community-associated (COCA) infections are defined as cases of individuals who had not been discharged from the same reporting trust in the 84 days prior to their specimen date. Rates of COCA infection in England have been rising consistently since financial year 2020/21. Rates of COCA infection across North Central London ICB increased at a similar rate between 2020/21 and 2022/23, however a fall in rate in financial year 2023/24 took the NCL ICB below that of the rate observed across England. Between 2023/24 and 2024/25, rates of infection increased from 6.06 per 100,000 population to 7 per 100,000 population in the NCL ICB.
Community-onset healthcare-associated (COHA) infections are defined as cases of individuals who were discharged from the same reporting trust in the 28 days prior to their specimen date. Rates of COHA infection in England have also been rising consistently since financial year 2020/21. On the contrary, rates of COHA infection across North Central London ICB fell during the same time. However, between 2023/24 and 2024/25, rates of infection increased from 1.62 to 3.68 per 100,000 population in the NCL ICB.
Seasonality
Nationally, there are no clear seasonal trends in hospital-onset healthcare-associated infections, and this has been the case since 2010/2011.
On the contrary, community-onset cases have consistently shown peaks in the second quarter of the financial year (July to September), which 29.3% of cases in 2024/25 occurring during that quarterly window. [9]
CDI trends by subgroup
Age & Sex: At the national level, rates of infection in most age groups across both males and females declined between 2007/08 to 2024/25. Although rates of CDI overall decreased in both sexes, females now account for a higher proportion of cases in each age group. Decreases in CDI rates were observed across all groups except the 2–14 years age group, where the rate increased in both males and females. Despite significant reductions since 2007/08, CDI rates have shown an upward trend across most age–sex groups since 2020/21. This increase is particularly pronounced in those aged 85 years and over, where rates have risen consecutively year on year through to 2024/25.[9].
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 CDI since recording for ethnicity began in 2017/2018.[9]
Deprivation: Nationally, crude and age-standardised rates of CDI in the most deprived quintile are significantly higher than the equivalent rates in the least deprived quintile. [9]
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 [10]
- 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.[11]
- Effective hand hygiene using soap and water and monitoring for hand hygiene compliance in healthcare settings.[11]
- Isolation of individuals with known or suspected CDI a single room with ensuite toilet facilities / a dedicated commode.[11]
- Use of aprons and gloves when caring for a patient / resident with CDI / cleaning the environment.[11]
Conclusion
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 linked to CDI 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.
References
[1]
Czepiel J, Dróżdż M, Pituch H, Kuijper EJ, Perucki W, Mielimonka A, et al. Clostridium difficile infection: review. Eur J Clin Microbiol Infect Dis 2019;38:1211–21. https://doi.org/10.1007/s10096-019-03539-6.
[2]
Public Health Scotland. Guidance on prevention and control of Clostridioides difficile Infection (CDI) in community-based settings in Scotland 2024. https://publichealthscotland.scot/publications/guidance-on-prevention-and-control-of-clostridioides-difficile-infection-cdi-in-community-based-settings-in-scotland/guidance-on-prevention-and-control-of-clostridioides-difficile-infection-in-community-based-settings-in-scotland-version-1-new/background-to-cdi/risk-factors-for-developing-cdi/ (accessed December 1, 2025).
[3]
Haran JP, Ward DV, Bhattarai SK, Loew E, Dutta P, Higgins A, et al. The high prevalence of Clostridioides difficile among nursing home elders associates with a dysbiotic microbiome. Gut Microbes 2021;13:1897209. https://doi.org/10.1080/19490976.2021.1897209.
[4]
C. Difficile (Clostridioides difficile) Policy for Care Home settings n.d. https://www.infectionpreventioncontrol.co.uk/resources/clostridioides-difficile-policy-for-care-home-settings/ (accessed January 5, 2026).
[5]
NHS. Clostridioides difficile (C. diff) 2025. https://www.nhs.uk/conditions/c-difficile/ (accessed November 12, 2025).
[6]
UK Health Security Agency, Department for Health and Social Care. Clostridioides difficile infection: How to deal with the problem 2024. https://www.gov.uk/government/publications/clostridium-difficile-infection-how-to-deal-with-the-problem (accessed November 12, 2025).
[7]
National Institute for Health and Care Excellence. Overview | Clostridioides difficile infection: Antimicrobial prescribing | Guidance | NICE 2021. https://www.nice.org.uk/guidance/ng199/ (accessed November 12, 2025).
[8]
UK Health Security Agency. Increase in Clostridioides difficile infections (CDI): Current epidemiology, data and investigations – Technical report 2025. https://www.gov.uk/government/publications/increase-in-clostridioides-difficile-infections-technical-report/increase-in-clostridioides-difficile-infections-cdi-current-epidemiology-data-and-investigations-technical-report (accessed November 8, 2025).
[9]
UK Health Security Agency. Annual epidemiological commentary: Gram-negative, MRSA, MSSA bacteraemia and C. Difficile infections, up to and including financial year 2024 to 2025 2025. https://www.gov.uk/government/statistics/mrsa-mssa-and-e-coli-bacteraemia-and-c-difficile-infection-annual-epidemiological-commentary/annual-epidemiological-commentary-gram-negative-mrsa-mssa-bacteraemia-and-c-difficile-infections-up-to-and-including-financial-year-2024-to-2025 (accessed December 1, 2025).
[10]
UK Health Security Agency. Clostridioides difficile infection: Updated guidance on management and treatment 2022.
[11]
Department of Health. High Impact Intervention No. 7 - Care bundle to reduce the risk from Clostridium difficile 2007.