Anderson TL, McGregor A. Evaluation of the Clearview Clostridium difficile Toxin A Test and various selective culture media in comparison with the cytotoxin assay for the diagnosis of Clostridium difficile-associated diarrhoea.
Pathology 2003;
35:244-7. [PMID:
14506970 DOI:
10.1080/0031302031000123236]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
AIM
Clostridium difficile is the major pathogen associated with nosocomial diarrhoea. We evaluated the performances of a commercially available toxin A enzyme immunoassay (EIA; Clearview C. difficile Toxin A Test), culture and tissue culture cytotoxin assay in the diagnosis of C. difficile-associated diarrhoea.
METHODS
Comparative test performance was determined from data obtained from 166 faecal samples. The initial analysis compared the performance of toxin A EIA and culture with that of cytotoxin assay, this being defined as a 'laboratory gold standard'. A second analysis compared the individual performance of the toxin A EIA, culture and cytotoxin assay using a combined clinical and laboratory diagnostic assessment as a 'clinical gold standard'. In a parallel, study three selective culture media were compared.
RESULTS
From the initial analysis, the sensitivity and specificity of the methods were, respectively, 84.6 and 65.4% for the toxin A EIA, and 38.5 and 93.5% for culture. From the second analysis, the sensitivity and specificity of the methods were, respectively, 100 and 67.5% for the toxin A EIA, 63.6 and 96.7% for culture and 72.7 and 98.0% for cytotoxin assay. Media containing d-cycloserine 250mg/L and cefoxitin 8mg/L performed best, growing 88.2% of the isolates.
CONCLUSION
The toxin A EIA we evaluated had poor specificity in the diagnosis of C. difficile-associated diarrhoea. We conclude that in our laboratory the combination of culture and cytotoxin assay is a preferred approach to the diagnosis of C. difficile-associated diarrhoea.
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