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C. difficile infection (CDI)

Clostridium difficile, a spore-forming bacterium, is the major cause of healthcare associated diarrhoea in developed countries (1-3).

C. difficile is widely underdiagnosed (4). The largest ever epidemiological study of CDI in Europe, EUCLID, showed a 48-fold variation in country-specific testing rates and highlighted that 23 % of CDI cases were underdiagnosed. This means about 40.000 missed CDI diagnoses per year in the 482 laboratories that participated in the study. The true number of undiagnosed or misdiagnosed CDI was, however, assumed to be much greater considering that there are about 8.000 hospitals in Europe. Absence of clinical suspicion of CDI and the poor sensitivity of diagnostic testing methods were considered the reasons behind the CDI underdiagnosis.

Updates to C. difficile diagnostic guidelines

The European Society of Clinical Microbiology and Infectious Diseases (ESCMID) has recently released new guidelines on best practice methods to diagnose C. difficile infection (5). The latest document updates the original 2009 guidelines and includes recommendations concerning the use of new diagnostic technologies such as nucleic acid amplification tests (NAAT). The study that underpins the new guidelines was initiated in June 2014. 

The authors of the C. difficile diagnostic guidelines (5) strongly recommend using a two-step algorithm approach for routine C. difficile testing. According to the authors, single, standalone tests, are not reliable. Two different algorithms to test C. difficile were described:

  • The testing begins with either a NAAT or GDH EIA test. Positive test results should be followed up with a toxin A/B EIA test to confirm the result.
  • The testing begins with both a GDH EIA and toxin A/B EIA test. If both tests are positive, CDI is likely to be present. If GDH is positive and toxin A/B negative, NAAT or toxigenic culture (TC) can be done.

The updated recommendation points out that the clinical signs and symptoms will have to be taken into account with all patients when making a diagnosis.

The updated ESCMID’s guideline was published in August 2016 in Clinical Microbiology and Infection.

Make the most of your resources

Orion GenRead® C. difficile, a novel NAAT test, can be used as a part of recommended two-step algorithm for routine C. difficile testing.The test can be used for identification of toxigenic C. difficile directly from a faecal sample collected from a patient suspected of having CDI.

The Orion GenRead C. difficile test targets the toxin B gene (tcdB) of C. difficile pathogenicity locus (PaLoc). It is a flexible benchtop solution consisting of a small instrument and the ready-to-use Orion GenRead C. difficile kit. The system enables accurate and affordable nucleic acid based testing for C. difficile with the result available in less than one hour. 

The Orion GenRead C. difficile test is a tool for optimal management of patients suspected of having CDI and it promotes efficient use of healthcare resources.

Orion GenRead C. difficile


Published August 30, 2016 


  1. Magill S.S., Edwards, J.R., Stat, M., Bamberg, W., Beldavs, Z.G., Dumyati, M.S.G., Kainer, M.A., Lynfield, R., Maloney, M., McAllister-Hollod, L., Nadle, J., Ray, S.M., Thompson, D.L, Wilson, L.E. & Fridkin, S.K.  (2014). Multistate Point-Prevalence Survey of Health Care-Associated Infections. The New England Journal of Medicine; 370:1198-208.
  2. Surawicz C.M., Brandt, L.J., Binion, D.G., Ananthakrishnan, A.N., Curry, S.R., Gilligan, P.H., McFarland, L.V., Mellow, M. & Zuckerbraun, B.S. (2013). Guidelines for Diagnosis, Treatment, and Prevention of Clostridium diffi cile Infections. The American Journal of Gastroenteroly, 108, 478–498.
  3. Awad M.M., Johanesen, P.A., Carter, G.P., Rose, E. & Lyras, D. (2014). Clostridium difficile virulence factors: insights into an anaerobic spore-forming pathogen. Gut Microbes, 5(5), 579-593.
  4. Davies K.A., Longshaw, C.M., Davis, G.L., Bouza, E., Barbut, F., Barna, Z., Delmée, M., Fitzpatrick, F., Ivanova, K., Kuijper, E., Macovei, I.S., Mentula, S., Mastrantonio, P., von Müller, L., Oleastro, M., Petinaki, E., Pituch, H., Norén, T., Nováková, E., Rupnik, M., Schmid, D. & Wilcox, M.H. (2014). Underdiagnosis of Clostridium difficile across Europe: the European, multicentre, prospective, biannual, point-prevalence study of Clostridium difficile infection in hospitalised patients with diarrhoea (EUCLID). The Lancet Infectious Diseases, 14, 1208-1219.
  5. Crobach, M.J.T., Planche, T., Eckert, C., Barbut, F., Terveer, E.M., Dekkers, O.M., Wilcox, M.H. & Kuijper, E.J. (2016). European Society of Clinical Microbiology and Infectious Diseases: update of the diagnostic guidance document for Clostridium difficile infection. Clinical Microbiology and Infection, 22, S63-S81.