Background: Accurate diagnostic methods for Clostridium difficile infection (CDI) are required for
optimal patient management, appropriate implementation of infection control measures and
surveillance. An assay that also provides rapid results, is easy to implement in a routine diagnostic
lab and is cost-effective would be ideal. Laboratory testing for Clostridium difficile infection is
rapidly evolving. Recently published literature has shown that immunoassays for toxin detection,
whilst being cheap and easy to implement, lack sensitivity. Molecular diagnostics that are sensitive
and provide rapid results are now available. However, the high cost of these assays is of concern. As
reflected in the literature the optimal test or testing algorithm for Clostridium difficile infection
diagnosis is not clear.
Objectives: This study aimed to compare the performance of a real-time PCR assay and two
immunoassays, and to establish the optimal testing strategy for Charlotte Maxeke Johannesburg
Academic Hospital (CMJAH).
Methods: Using toxigenic culture as the gold standard, the Roche PCR assay for the detection of the
tcdC gene, the Immuno Card Toxins A & B immunoassay and the C. Diff Quik Chek Complete
immunoassay were evaluated as stand alone assays and as part of testing algorithms.
Results: The sensitivity, specificity, positive predictive value and negative predictive value of the
various assays and algorithms ranged from 38% to 81%, 98% to 100%, 92% to 100% and 85% to
95%, respectively. The charge per sample tested varied widely depending on the assay and algorithm
used. The maximum turnaround time ranged between four and twenty four hours.
Conclusion: The algorithm combining glutamate dehydrogenase and toxin immunoassay testing of
all samples followed by PCR testing of only a subset of samples, performed the best, providing
accurate results rapidly and cost-effectively.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/13905 |
| Date | 20 February 2014 |
| Creators | Nana, Trusha |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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