Public Health Agency

Clostridium difficile



Clostridium difficile (C. difficile) is a spore-forming anaerobic gram positive bacterium. Spores may be ingested following contact with a contaminated environment, other patients or from the hands of staff that may be contaminated with C.difficile spores. C. difficile is a major cause of antibiotic associated diarrhoea and colitis, healthcare associated infections (HCAI’s) that mostly affect elderly patients with other underlying diseases.

Certain antibiotics may change the natural balance of bacteria in the bowel; this enables C.difficile to multiply and produce toxins that can cause diarrhoea. Symptoms of C.difficile infection (CDI) are similar to those of other diarrheal illness and may include stomach cramps, fever, nausea, loss of appetite and passing blood.  The stools of patients with Clostridium difficile infection have a characteristic unpleasant smell.

C. difficile acquisition may result in asymptomatic carriage, loose stools or profuse diarrhoea which can result in life-threatening pseudo-membranous colitis and toxic megacolon. CDI is most common in people over the age of 65 years but any age group may be susceptible, with the exception of very young children (<2yrs).

Large outbreaks of C. difficile with significant mortality have been documented in healthcare facilities and often resulted in public enquiries. Robust management to prevent secondary spread is essential.

Clinical picture

The symptoms of CDI range from mild diarrhoea, to bloody diarrhoea and abdominal pain which can lead to dilation and life threatening perforation of the colon requiring major abdominal surgery.

Symptoms may start as early as a few days after starting a course of antibiotics but may be delayed until after the course has been completed. Most antibiotics have been implicated in the development of CDI but those most commonly associated are:

  • Cephalosporin’s: 2nd generation onwards
  • Clindamycin
  • Quinolones e.g. ciprofloxacin
  • B-lactamase inhibitor combinations e.g. co-amoxiclav

Occasionally a single dose of antibiotic can be associated with the development of CDI.

The first requirement for CDI to occur is exposure to the bacterium or its spores. In some patients C.difficile may already be present in the gut without producing symptoms of infection i.e. colonisation. However in the majority of cases, it is thought that exposure prior to infection occurs when a patient ingests the spores. The spores are not destroyed by the acid produced in the stomach and travel to the large bowel. The bowel flora (term given to the multitude of organisms that normally live in the bowel) normally holds any C.difficile present in check. However if the flora is altered because the patient is taking/has had recent antibiotics or has had another intervention such as radiotherapy, C. difficile is able to proliferate and produce toxins A and B. In susceptible patients, the toxins produce inflammation and tissue damage of the large bowel (colon) leading to the development of CDI.

Susceptible patients

The possibility of CDI should be considered when patients with diarrhoea have had:

  • Antibiotics (current / recent)
  • Multiple healthcare interventions that include admission to hospital
  • Serious underlying illness
  • Recent surgical procedures (in particular bowel procedures)
  • Immunocompromising conditions especially patients on cancer treatment
  • Proton Pump Inhibitors (PPIs). This group of drugs produces pronounced and long-lasting reduction of gastric acid production. As their use has been associated with the development of CDI, they should be used prudently.

Elderly patients/residents with multiple illnesses are more susceptible to developing CDI. CDI does not occur in babies, although spores can be commonly found in their gut, and is extremely rare in young children. However, it has been known to cause death in people as young as thirty and should be considered as a possible diagnosis if a young immunocompromised adult is symptomatic.

Diagnosis of CDI

Confirmation of infection is by the detection of C. difficile toxins A and B in stool samples from a symptomatic patient. As an epidemiological aid, C.difficile isolates can be ribotyped by the laboratory. If this is required, the typing will be requested by the Infection Prevention and Control Team.

Disease Severity

This is usually based on the number and frequency of diarrheal episodes in combination with raised inflammatory markers. Diarrheal episodes can be classified using the Bristol Stool Chart, an aid designed to classify the form of human stools into seven categories: Types 1-2 indicate constipation, with 3-4 being the ideal stools as they are easy to pass while not containing any excess liquid, and 5-7 tending towards diarrhoea.

Mild  - < 3 episodes of diarrhoea (Type 5 to 7 - Bristol Stool chart) per 24 hour period and a normal WCC. 

Moderate - 3 to 5 episodes of diarrhoea (Type 5 to 7 - Bristol Stool chart) per 24 hour period and a raised WCC, but less than 15,000/mm3 (15 x 109/L).  

Severe - The number of episodes of diarrhoea (Type 5 to 7 on the Bristol Stool chart) is considered to be a less reliable indicator of severe disease.  Also the patient has a WCC >15,000 (15 x 109/L) or a temperature of > 38.5°C or acute rising serum creatinine (e.g. >50% increase above baseline) or evidence of severe colitis (abdominal or radiological signs). 

Life threatening - Includes hypotension, partial or complete ileus or toxic megacolon, or CT evidence of severe disease.

Management of Clostridium difficile infection

Patient Management

  • All patients with C.difficile infection should be nursed in a single room to prevent the spread of infection to others. Sometimes patients are cohorted in a bay with others who have CDI.
  • Each patient with C.difficile must have their own toilet or commode. Healthcare staff should wear disposable gloves and aprons when providing care to a patient with C.difficile and decontaminate their hands, using liquid soap and water, before leaving the room. Note that hand sanitisers do not inactivate C.difficile spores.
  • Patient’s nightwear and bed linen should be changed daily when CDI is present.
  • Patient’s rooms should have enhanced cleaning at least daily whilst they are symptomatic. 

Clinical Management

  • Medical staff should consider CDI as a diagnosis in its own right and a stool sample should be sent to the laboratory for toxin detection as a matter of urgency.
  • A daily review must include monitoring bowel function, fluid and electrolyte balance and the nutritional status of the patient.
  • STOP ANTIBIOTICS if possible.
  • Treatment options depend on clinical severity and include either: Metronidazole and/or oral Vancomycin. Staff should familiarise themselves with their local antibiotic policy (insert link to AMR section) for C.difficile.
  • In some cases prolonged C. difficile diarrhoea should be managed with a weekly review by a Multidisciplinary Team (MDT) e.g. Microbiologist, Pharmacist, Gastroenterologist, IPC.
  • Repeat faeces specimens to establish clearance of C. difficile are not necessary.
  • Patients who develop diarrhoea following a symptom free period may have been re-infected or have relapsed. These patients must be isolated immediately. A faeces specimen should be sent for C. difficile toxin testing if it is more than 28 days since the previous positive toxin result, and a repeat test is clinically indicated.    

The following table outlines the actions that are required for sporadic cases, localised clusters of cases and outbreaks of CDI:

Managerial Responsibilities

Managers are responsible for ensuring staff are aware of the Clostridium difficile policy and comply with all aspects, with particular reference to:

  • Prompt isolation of patients
  • The timely taking of stool specimens
  • Cleaning of the environment
  • Antimicrobial stewardship
  • Effective hand hygiene

Managers are also responsible for ensuring adequate staffing levels, implementing increased cleaning and ensuring adequate supplies of equipment, particularly consumables to ensure compliance with this policy.

If there is an outbreak, management will take responsibility for actions including ward closure on advice from the Infection Prevention & Control Team/ Outbreak Control Team.


The most important aspects of Clostridium difficile (C. difficile) are:

1.     Isolation of infected patients

2.     Hand washing with soap and water

3.     Personal protective equipment (gloves and aprons)

4.     Prudent antibiotic prescribing

5.     Enhanced environmental cleaning



  1. High Impact Intervention No 7: Care bundle to reduce the risk from Clostridium difficile. Available at:

2.     Public Health England. Updated guidance on the management and treatment of Clostridium difficile infection. [Online]. London: Public Health England, May 2013. Available at:

  1. Public Inquiry into the Outbreak of Clostridium difficile in Northern Trust Hospitals, Northern Ireland.

Click to download the C. difficile Leaflet