Evaluation of a new enzyme immunoassay for Clostridium difficile toxin A (original) (raw)
Related papers
Enzyme immunoassay for detection of antibody to toxins A and B of Clostridium difficile
Journal of Clinical Microbiology, 1983
An enzyme immunoassay (enzyme-linked immunosorbent assay [ELISA]) to detect hamster antibody to toxins A and B of Clostridium difficile was developed in which toxin preparations are used to coat the solid phase. The specificity of the assay was supported by blocking tests with the toxin preparations and proteins from a nontoxigenic strain. Sera from immunized and control hamsters were tested by this technique, and results were compared with those from a cytotoxicity neutralization assay. Antibody to toxins A and B assayed by ELISA showed a close quantitative correlation with antibody titers obtained by cytotoxicity neutralization. The ELISA assays described appear to provide a sensitive, specific, and practical method to define the prevalence of antibody to C. difficile toxins. These assays could be readily applied to human sera to examine and study the immune response of patients with C. difficile-induced disease. Clostridium difficile has been implicated as
Concordance Between Two Enzyme Immunoassays for the Detection of Clostridium difficile Toxins
Archives of Medical Research, 2010
Background and Aims. The diagnosis of Clostridium difficile-associated disease (CDAD) is based on the detection of toxins from stool samples. There are several immunoassays for this purpose. The aim of this study was to determine the concordance between the two immunoassays and their performance in comparison to the toxigenic culture as part of the initial evaluation of a suspected case of CDAD. Methods. All fecal samples submitted for detection of C. difficile toxins during a 5-month period to our laboratory were analyzed by two immunoassays, VIDAS Toxin CDA/B assay (BioMerieux) and ImmunoCard Toxins A/B (Meridian Bioscience). We cultured on cycloserine-cefoxitin-fructose agar and PCR was used for detection of toxigenic genes. Real-time PCR was performed directly from samples to detect the tcdC gene. Results. At the end of the study we processed 230 samples, 13 were positive using VI-DAS CDA/B (5.6%), and 14 using ImmunoCard A/B (6.0%); k coefficient was 0.857. With ImmunoCard A/B we obtained a sensitivity of 80%, a specificity of 99%, positive predicitive value (PPV) 86% and negative predictive value (NPV) 98%, as compared to toxigenic culture. For VIDAS CDA/B we obtained a sensitivity of 90%, a specificity of 98%, PPV 69% and NPV 99%, compared to the same standard. There were seven undetermined results (3.0%) by VIDAS CDA/B. Five of these had a positive culture and all the patients had symptoms of CDAD. Considering these undetermined results as positive, we calculated a sensitivity of 93%, specificity of 97%, PPV 71% and NPV of 99% for this test, and a k of 0.856. Both immunoassays showed similar results and are suitable for the initial evaluation of patients with suspected CDAD. Conclusions. Our data suggest that an undetermined result of VIDAS CDA/B should be considered as positive if CDAD is suspected. Additionally, both immunoassays showed similar results and are suitable for the initial evaluation of patients with suspected CDAD. Ó 2010 IMSS. Published by Elsevier Inc.
Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases, 2015
The optimal approach in laboratory diagnosis of Clostridium difficile infection (CDI) is still not well defined. Toxigenic culture (TC) or alternatively fecal toxin assay by cell cytotoxicity neutralization assay are considered the gold standard, but these methods are time-consuming and labor intensive. In many medical centers diagnosis of CDI is therefore still based on fecal toxin A/B enzyme immunoassay (EIA) directly from stool alone, balancing cost and speed against limited diagnostic sensitivity. The aim of the study was to assess in which patient population the additional workload of TC is justified. All consecutive stool specimens submitted for diagnosis of suspected CDI between 2004 and 2011 at a tertiary care center were examined by toxin-EIA and TC. Clinical data of patients with established diagnosis of CDI were collected in a standardized case-report form. From 12'481 stool specimens submitted to the microbiological laboratory, 480 (3.8%) patients fulfilled CDI crite...
Journal of Clinical Microbiology, 1993
Four commercial enzyme immunoassays (EIAs) for the detection of Clostridium difficile toxin A have recently been developed and marketed (Premier, Meridian Diagnostics, Cincinnati, Ohio; VIDAS, bioMerierux Vitek, Inc., Hazelwood, Mo.; Tox-A-Test, TechLab, Blacksburg, Va.; and Bartels, Baxter Diagnostics, McGaw Park, Ill.). The performances of these EIAs were compared with those of the tissue culture cytotoxicity assay and a definition of C. difficile-associated disease based on both laboratory and clinical criteria for 329 clinical specimens. Two EIAs (Premier and VIDAS) showed good overall agreement (96 and 95%, respectively) with the cytotoxicity assay. However, they were less sensitive (84 and 71%, respectively) than the Bartels (94%) or Tox-A-Test (93%) EIAs. The Bartels and Tox-A-Test assays were much less specific, resulting in poor positive predictive values (56%) of the two assays when compared with that of the cytotoxicity assay. Tox-A-Test had the added drawback of having a...