Clostridium difficile (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
Collection container (including preservatives):
Collect specimens in appropriate CE marked leak proof containers
and transport specimens in sealed plastic bags.
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
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.
Measurement units: Not applicable
Biological reference units: Not applicable
Turn round time for provisional result (calendar
days): 24 hrs
Turn round time to final result (calendar
days): 48-72 hrs. 95% of samples tested for C.
difficile (GDH) are reported within 24 hrs.
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.
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.
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
- 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