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Clostridium difficile GDH and Toxin (Bacteriology)

C. difficile is a Gram positive, spore forming, strictly anaerobic rod, so named because of the difficulty in original culture and characterisation. Toxigenic strains produce large protein toxins A and B, both being major virulence factors. Most disease associated with C. difficile is intestinal though C. difficile may be isolated from blood or tissues.

General information

Collection container (including preservatives): Collect specimens in appropriate CE marked leak proof containers and transport specimens in sealed plastic bags.

Clostridium difficile

Specimen type: Faeces

Collection: Specimen may be passed into a clean, dry, disposable bedpan or similar container and transferred into a CE marked leak proof container. The specimen is unsatisfactory if any residual soap, detergent or disinfectant remains in the pan.

Specimen transport: Compliance with current postal and transportation regulations is essential.

Clinical samples should be collected into a sterile leak-proof container in a sealed plastic bag.  Specimens should be transported and processed as soon as possible. If processing is delayed refrigeration is preferable to storage at room temperature.

Type and volume of sample: A liquid specimen of 1-2 mL is sufficient for culture and toxin detection.
1 gram (large pea-size) of unformed specimen.

Special precautions: Formed stools are unsuitable for investigation for C. difficile.

Laboratory information

Measurement units: Not applicable

Biological reference units: Not applicable

Turn round time for provisional result (working days): 1 day

Turn round time to final result (working days): 2 days. 95% of samples tested for C. difficile (GDH) are reported within 24 hrs.

Clinical information

Clinical decision points: Not applicable

Factors known to significantly affect the results: The detection of C. difficile is dependent on the number of organisms present in the sample, reliable results are dependent on correct specimen collection, handling, and storage.


Interpretation of toxin results in children less than 2 years old should be treated with caution.


Clostridium difficile Ribotyping Service

The Manchester Laboratory has been identified as one of six Regional Laboratories to provide a Clostridium difficile ribotyping service as part of the Clostridium difficile Ribotyping Network (CDRN).  Ribotyping will be provided for the North West Region and we will eventually have funding for up to 1,000 isolates per year.

Prior to sending your specimens to Manchester, please contact ALL of the named individuals listed below via email to ensure that specimens comply with the acceptance policy and that the CDRN forms are completed with all of the information needed.  The current turn around time is 14 days.

Dr E Kaczmarski
Tel: 0161 276 5699 
Dr A Dodgson
Tel: 0161 276 6010 
Dr K Dodgson Tel: 0161 276 5746
Dr A Birtles Tel: 0161 276 5689 



Specimens will not be accepted unless all patient/sample data has been entered onto the CDRN web system and the sample is accompanied by a completed Specimen Request Form, generated from the CDRN web system.

Copies of the following documents are available from https://nww.cdrn.nhs.uk and http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/ClostridiumDifficile

  • Guidance document with selection criteria
  • Guidance document for access to the ribotyping service
  • Clostridium difficile specimen request form (one form for each specimen)
  • Guidance on storage of faecal specimens

(Last reviewed October 24th 2017)