Clostridioides difficile infection (CDI) In Adults - Diagnosis and Management of

Publication: 20/05/2008  
Next review: 02/09/2025  
Clinical Guideline
ID: 1254 
Approved By: Improving Antimicrobial Prescribing Group 
Copyright© Leeds Teaching Hospitals NHS Trust 2023  


This Clinical Guideline is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Diagnosis and Management of Clostridioides Difficile Infection (CDI) In Adults (>18 Years of age)

Click here to view the child guideline (<18 years)


Consider Clostridiodes difficile (previously Clostridum difficile; C.difficile) infection in all patients with loose stools, particularly in those who have recently received antibiotic treatment. Check the patient is not on laxatives. If the patient is on laxatives, these should be stopped and a sample sent for CDI testing only if type 5-7 stool persists 24hrs after stopping laxatives. For patients with a suspected diagnosis of CDI the following diagnostic tests should be taken to confirm diagnosis:

All patients with type 5-7 stools, at least 24 hours after stopping laxatives. 

Stool sample for CDI testing - see table below for interpretation of results information.

Do not send samples if the patient has tested CDI toxin positive within the last 28 days, unless symptoms previously resolved and now recurred.

 FBC & U&Es, LFTs/albumin.

Severe or life-threatening infection

Abdominal X-ray and/or CT abdomen if colitis suspected

For patients who have suspected or confirmed CDI please ensure Infection Prevention & Control (IPC) guidance is followed with regards to source isolation

Clinical Interpretation of Clostridiodes difficile Laboratory Test Results

CDI is caused by the production of toxins by toxigenic strains of C. difficile bacteria. Samples sent for C. difficile testing go through a series of steps to determine the following:

  • Is C. difficile present? 
  • If so, does the strain carry the toxin gene? 
  • Is the toxin being produced? 

Laboratory Test result


C. difficile screen negative

No C. difficile infection or colonisation
No further testing undertaken.

C difficile screening test positive, toxin result to follow

Potential C. difficile excretor (colonisation).
No change to current management advised with this result (see treatment section).

Further testing required: toxin detection and/or PCR detection of toxin genes.

C. difficile toxin gene NOT detected

A toxigenic strain of C. difficile has not been detected on PCR testing. 
No further testing undertaken.
This result does not indicate CDI

C. difficile toxin gene detected, awaiting toxin result

The patient is a carrier of a toxigenic strain of C difficile
Toxin production testing is required.

C. difficile toxin NOT detected, but toxigenic strain present.

The patient is a carrier of a toxigenic strain of C. difficile, but there is no active toxin production.
This result does not usually indicate CDI, clinical correlation is advised

C. difficile toxin detected

C. difficile infection probable; treatment usually required

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Review medicines and:


  • Laxatives
  • All non-C. difficile antibiotics if at all possible (see below).
  • Any non-essential medicines causing gastrointestinal effects
  • Loperamide - do not use if suspected CDI.

Consider stopping:

  • ACE inhibitors, NSAIDs, diuretics if concerned about dehydration
  • Proton pump inhibitors e.g. omeprazole, lansoprazole

Additional medical management

  • Correct dehydration and electrolyte abnormalities

Adjunctive treatments to consider for severe/ life-threatening CDI not responding to initial antimicrobial +- surgical management.

  • Discuss with infectious diseases or microbiology team whether appropriate for:
  • Intravenous immunoglobulin 400mg/kg stat (local panel approval needed - see link below*)
  • Faecal microbiota transplantation (FMT)
  • * LTHT Immunoglobulin guidance - commissioning criteria policy can be found here

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For suspected or confirmed CDI review existing antibiotic treatment and STOP unless essential. If non-CDI antibiotics need to continue, ensure that microbiology results have been reviewed and the most narrow spectrum antibiotic is prescribed. Please refer to individual guidelines for directed therapy options.

CDI treatment may be started whilst awaiting results if deemed clinically appropriate by the responsible clinician.



Non-severe to moderate

Diarrhoea without features of severe or life-threatening infection


Any one of: Raised WCC >15 x 109/L, AKI, temperature of >38.5°C, evidence of severe colitis e.g. guarding, abdominal tenderness (BO >7x/day)



Any one of: Hypotension unresponsive to fluid challenge, partial or complete ileus, toxic megacolon or CT evidence of severe disease, lactate >5 mmol/L.






Recommended treatment (if no additional risk factors)

Alternative to be used if:

High risk of recurrence (e.g. elderly/frail, need for ongoing concomitant antibiotics)


Symptoms not improving after the 1st 7 days of Vancomycin electronic Medicines Compendium information on Vancomycin treatment

within 12 weeks of previous symptom resolution

after 12 weeks of previous symptom resolution


Duration: 10 days

Duration: 10 days

Non-severe to moderate

ORAL/NG 2 Vancomycin electronic Medicines Compendium information on Vancomycin 125mg 6 hourly

Fidaxomicin electronic Medicines Compendium information on Fidaxomicin1 200mg 12 hourly

Fidaxomicin electronic Medicines Compendium information on Fidaxomicin1  200mg 12 hourly

Vancomycin electronic Medicines Compendium information on Vancomycin 125mg 6 hourly OR ORAL/NG Fidaxomicin1 200mg 12 hourly


Vancomycin electronic Medicines Compendium information on Vancomycin 125mg 6 hourly



Fidaxomicin electronic Medicines Compendium information on Fidaxomicin1 200mg 12 hourly


Fidaxomicin electronic Medicines Compendium information on Fidaxomicin1 200mg 12 hourly

UNLESS received fidaxomicin1 within previous 28 days - in which case use ORAL/NG2
Vancomycin electronic Medicines Compendium information on Vancomycin 125mg 6 hourly

Life-threatening/profound ileus

Vancomycin electronic Medicines Compendium information on Vancomycin 500mg 6 hourly AND IV metronidazole 500mg 8 hourly

AND urgent surgical review to consider colectomy

AND consider non-antimicrobial adjuncts above.

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If the patient has more than one relapse/recurrence of CDI (i.e. 3 or more CDI episodes) then start treatment as per above guidance for a second episode and refer to infectious diseases for advice as pulse tapered vancomycin3, FMT or bezlotoxumab may be considered.

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Review stool sample results and stop CDI treatment if C. difficile screen/toxin negative. If on-going diarrhoea then send samples for other causes of diarrhoea (if not already done so).

If on-going clinical suspicion of CDI but C. difficile toxin negative, then discuss the case with infectious diseases and/or microbiology.

Clinical judgement is needed to review whether C. difficile treatment is ineffective, note that diarrhoea may take 1 to 2 weeks to resolve.

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Patients should not be offered probiotics, prebiotics or antibiotics for the prevention of CDI.

All antibiotic treatment should be regularly reviewed and stopped if no longer required.

Robust hand hygiene and IPC procedures should be followed for ALL patients. Patients with C. difficile infection and colonisation should be advised to maintain good hand hygiene themselves for prevention of further relapses.

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  1. Pregnancy: Fidaxomicin should be avoided in pregnancy. Vancomycin electronic Medicines Compendium information on Vancomycin may be used in pregnancy if the risk outweighs the benefit. Note for life-threatening C. difficile infection, metronidazole may also be used in pregnancy if the risk outweighs the benefit.
  2. Oral/enteral preparations:
    1. Vancomycin is available as a capsule to be administered orally. The injection is also licensed to be administered orally and information on how to do this can be found in the Patient Information Leaflet.  A liquid preparation may be prepared by pharmacy if needed. Contact your ward pharmacist to order this.
    2. Fidaxomicin electronic Medicines Compendium information on Fidaxomicin granules are available for patients unable to swallow tablets. Fidaxomicin electronic Medicines Compendium information on Fidaxomicin tablets may be crushed and dispersed for administration enterally, including via feeding tubes, however it should be noted that this method is unlicensed and the patient should be informed of this.
  3. Pulse tapered vancomycin regimen which may be given for recurrent CDI: after the initial 10 days treatment: vancomycin 125mg QDS 1 week, then 125mg TDS 1 week, then BD 1 week, then OD 1 week, then alternate days 1 week, then every 3 days for 1 week then stop.


Record: 1254
Clinical condition:

Clostridioides difficile infection (CDI)

Target patient group: Adults (>18 Years of age)
Target professional group(s): Pharmacists
Secondary Care Doctors
Adapted from:

Evidence base

  • NICE: Clostridioides difficile infection:antimicrobial prescribing NICE guideline [NG199] Published 23/07/21
  • UKHSA: Clostridioides difficile: guidance, data and analysis. The characteristics, diagnosis, management, surveillance and epidemiology of Clostridioides difficile (C.difficile). Last updated 6/09/21
  • NHS England Commissioning Criteria Policy Immunoglobulin 2021 (available electronically:
  • NICE Medical technologies consultation document – Faecal microbiota transplant for recurrent Clostridioides difficile infection. March 2022. Guidelines in Development (GID-MT566) - expected publication 30.08.22.

Approved By

Improving Antimicrobial Prescribing Group

Document history

LHP version 2.1

Related information

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