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Clostridioides Difficile (CDI) Information pack for general practitioners (Antimicrobial)


Clostridioides difficile is an anaerobic bacterium that is present in the gut of up to 3% of healthy adults, 20% of hospital patients and 66% of infants. However, C. difficile rarely causes problems in children or healthy  adults, as it is kept in check by the normal bacterial population of the intestine. When certain antibiotics disturb the balance of bacteria in the gut, C. difficile can multiply rapidly. Some strains of Cdifficile produce toxins.

For glossary of terms see Glossary.

Factors associated with risk of developing C. difficile infection (CDI)

  • Antibiotic exposure, especially long duration and >1 course in the previous 3 months, in particular the “4-Cs”, ciprofloxacin (quinolones), co-amoxiclav (broad spectrum penicllins,) clindamycin and cephalosporins (3rd generation).
  • Gastrointestinal surgery/manipulation.
  • Prolonged stay in healthcare settings.
  • Serious underlying illness.
  • Immunocompromised patients.
  • Advancing age (>80% are >65yrs).
  • Chronic renal disease.
  • Patients prescribed Proton Pump Inhibitors (PPI) ie omeprazole and lansoprazole.

Diagnosing CDI

Clinical symptoms include:

  • Varying degrees of diarrhoea from mild through to severe inflammation of the bowel in the form of pseudo membranous colitis, toxic megacolon, intestinal perforation and sepsis.
  • Fever.
  • Poor appetite/nausea.
  • Blood in stool.
  • Abdominal pain and tenderness.
  • Raise white cell count.

Specimens for CDI testing

Diarrhoea is defined as the passage of 3 or more loose or liquid stools per day, or more frequently than is normal for the individual (usually at least 3 times in a 24 hour period) that cannot be attributed to laxatives, enteral feeding, treatments etc. Or to underlying conditions such as colitis, overflow etc.

A faecal specimen of a least 2mL should be collected in blue top container with integral spoon. Ensure container is properly closed, do not overfill the container. Only samples that take the shape of the container will be tested by the labs.

All samples must be accompanied by a microbiology request form with C.difficile as the investigation required. Please indicate whether currently/recently receiving antibiotics and any clinical details. NB if the request form is not completed with the appropriate details, it may be rejected by the microbiology department.


GDH: this test detects the possible presence of the C.difficile bacteria within the gut. A positive result indicates C.difficile bacteria could be present within the specimen. It can represent colonisation with C. difficile. If the patient is symptomatic please contact microbiologist.

TOXIN A/B: if the GDH test is positive a TOXIN A/B test is then performed. This detects the presence or absence of the toxin produced by C.difficile that is responsible for the symptoms of C.difficile infection.

A negative test result does not necessarily exclude infection especially if clinical symptoms are highly suggestive. These cases should be discussed with the Consultant Medical Microbiologist or Infection Control Doctor.

Further stool specimens should not be sent following diagnosis of CDI. Samples sent within 28 days won’t be tested unless discussed with the Infection prevention & control team or the Consultant Microbiologist first. There is no requirement to send clearance samples. Advice on repeat samples should be sought from the Consultant Microbiologist when symptoms have recurred after the initial treatment.


The current NICE guidance statement does not recommend the use of probiotics, (NICE guidance statement 1.3.4 Do not advise people taking antibiotics to take prebiotics or probiotics to prevent C. difficile infection.)  The committee also noted the lack of convincing evidence of effect for prebiotics (oligofructose), which showed little difference in preventing  C. difficile-associated outcomes in the included studies. They concluded that prebiotics conferred no benefit and that people taking antibiotics should not be advised to take prebiotics to prevent C. difficile infection.
The committee agreed that there is some evidence of a small effect with probiotics in preventing C. difficile infection. However, there were many limitations in the evidence, including:

  • a high number needed to treat
  • aggregation of the results of different types of probiotics in meta-analyses
  • the lack of effectiveness when using confirmed cases only (in everyone, but particularly in children)

The committee also noted concerns from expert testimony about the high prevalence of C. difficile infection in the placebo arms of some studies, which does not reflect clinical practice in the UK. The single study done in a UK setting found no evidence of effect for probiotics in people aged over 65 years. They further noted that NHS England's guidance on conditions for which over the counter items should not routinely be prescribed in primary care states that probiotics should not routinely be prescribed.
The committee concluded that, because of concerns about the evidence base (including cost effectiveness), people taking antibiotics should not be advised to take probiotics to prevent C. difficile infection.

Patient Management: Review of prescribed medication

  • Check there are no other medicines prescribed that could cause diarrhoea eg laxatives, anti motility medication and stop if appropriate
  • Check there are no medicines prescribed which may exacerbate the condition eg anti-hypertensives particularly ACEIs, diuretics, metformin and stop if appropriate
  • Check no other medicine changes that could have changed bowel habit eg codeine
  • Check if any medicine that could cause immunosuppression (may be associated with more severe disease) and consider withholding.
  • Review the prescription of any antimicrobial and only continue if clinical benefit outweighs risk (discuss with Medical Microbiologist if required)

Review any prescription of a proton pump inhibitor or H2 antagonist with a view to stopping if possible (see appendix A).

Patient Management: Initial management

  • Consider cause of diarrhoea eg medicines, norovirus, impaction with overflow, chronic disease eg inflammatory bowel disease
  • Consider CDI if any of the following: antibiotic within last 3 months, recent surgical procedure, recent prolonged hospital stay, serious underlying disease, PPI or H2 antagonist prescribe
  • As soon as CDI suspected commence empiric treatment as per local protocol (Appendix B) and ensure Infection Prevention and Control Measures are in place. Do not wait on microbiology laboratory result.
  • Advise to obtain stool sample and next steps – eg treatment and monitoring requirements
  • Determine if hospitalisation is required based on severity markers eg temp>38·5°C, pulse> 100, BP<100systolic, suspicion of ileus or megacolon
  • Advise patient on: drinking enough fluids to avoid dehydration; preventing the spread of infection through optimal hand hygiene and cleaning; seeking medical help if symptoms worsen rapidly or significantly at any time.
  • Provide CDI Leaflet to patient

Patient Management: Ongoing management

  • Review after 3 days to determine response to treatment and be alert to signs of increasing severity (as above). If patient develops signs of severe C. difficile infection, discuss with Microbiologist and consider referral to hospital.
  • If no improvement or deterioration after 7 days treatment, contact Microbiologist
  • Consider checking infection markers (WCC, CRP and renal function)
  • In cases of recurrent CDI discuss further treatment with Microbiology
  • If in any doubt, contact Microbiologist for advice on management

Appendix A - Algorithm for the review of patients on proton pump inhibitors

Patient advice for stopping a Proton Pump Inhibitor (PPI)
Your GP will advise how your PPI should be stopped. This is likely to be in 4 stages:

  1. If you are on a high dose (more than 20mg) you will reduce to a lower dose for 1 month. This will be reduced again until you are taking the lowest dose of your PPI.
  2. You should then take the low-dose PPI on alternative days for 1 month. If you have any indigestion or heartburn on the non-medicine days, your GP will give you Peptac. Peptac is an antacid which neutralises the acid but doesn’t interfere with acid production.
  3. You should then reduce the dose again to take the PPI once or twice a week for 1 month, again using Peptac if needed.
  4. Finally you should stop the PPI. Any symptoms of indigestion of heartburn should clear up within 2 weeks of stopping the PPI as the level of stomach acid returns to normal. If you still have symptoms after 3 weeks consult your doctor.

Appendix B - Management of C.difficle in adults in the community (excluding pregnant patients and children - seek advice)


Appendix C - Tapering Vancomycin course (on advice from Microbiology)

Week  Dose  Frequency 
1 125mg 4 times a day 
125mg 3 times a day 
125mg twice daily 
125mg  once a day 
125mg  Every second day 
125mg  Every 3 days 

Total quantity to supply: 80 doses

Contact Numbers

Consultant Microbiologist 9am to 5pm Monday to Friday  Raigmore Office: 01463 704206
Consultant Microbiologist on call with above hours  Raigmore Switchboard: 01463 704000
Infection Control Nursing Team North Highland  Office: 01463 704434
Argyll & Bute Infection Prevention & Control Nurse  Mobile: 07887626539
Antimicrobial Pharmacist  Office: 01463 705886
Bleep: via Switchboard 2110 
Health Protection Team NHSH On-call  Office: 01463 704886
Raigmore Switchboard: 01463 704000

Further Information

Aide Memoire for General Practitioners on Management of Care Home Resident(s) with Diarrhoea and Clostridium difficile infection (CDI), Scottish Antimicrobial Prescribing Group Sept 2014 (Please note SAPG guidance no longer on SAPG website as of May 2022)

Guidance on Prevention and Control of Clostridium difficile Infection (CDI) in Care Settings in Scotland, 2017. V3

National Infection prevention and Control Manual for older people and adult care homes

Updated advice on Clostridioides difficile (C.diff) Infection (CDI), Scottish Antimicrobial Prescribing Group, Feb 2022

Clostridioides difficile infection: antimicrobial prescribing, NICE/PHE, July 2021

Last reviewed: 31/05/2022

Next review date: 30/06/2025

Author(s): NHS Highland Infection Prevention & Control Team.

Version: 3

Approved By: TAM Subgroup of the ADTC

Reviewer name(s): Catherine Stokoe, Infection Control Manager, Alison Macdonald, Area Antimicrobial Pharmacist Microbiology.

Document Id: AMT115