Is a two-step glutamate dehyrogenase antigen-cytotoxicity neutralization assay algorithm superior to the premier toxin A and B enzyme immunoassay for laboratory detection of Clostridium difficile?

Clinical Microbiology-Immunology Laboratories, UNC Hospitals, CB 7600, Chapel Hill, NC 27514, USA.
Journal of clinical microbiology (Impact Factor: 4.23). 05/2008; 46(4):1523-5. DOI: 10.1128/JCM.02100-07
Source: PubMed

ABSTRACT A two-step algorithm for the detection of Clostridium difficile by the use of C. Diff Quik Chek (TechLab, Blacksburg, VA) and a tissue culture cytotoxicity neutralization assay was found to be more sensitive than the widely used solid-phase enzyme immunoassay (EIA), the Premier toxin A and B EIA (Meridian Bioscience, Cincinnati, OH), and a newly developed, rapid single-test EIA for C. difficile toxins A and B (Tox A/B Quik Chek; TechLab).

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    ABSTRACT: Clostridium difficile is the most common cause of nosocomial infectious diarrhea. The incidence of C difficile infection (CDI) is increasing in both inpatients and outpatients, and outbreaks caused by a hypervirulent strain of C difficile are resulting in more severe disease. Moreover, community-associated CDI is occurring in persons who lack the traditional risk factors, which include antibiotic use, advanced age, and severe underlying disease. The clinical severity of CDI ranges from a mild, self-limited diarrheal illness to a fulminant, life-threatening colitis. Enzyme-linked immunosorbent assay is the most common laboratory method used for detection of C difficile toxins and can confirm the diagnosis within several hours. The choice of treatment should be based on disease severity. Oral metronidazole is generally regarded as the treatment of choice for mild to moderate CDI, while oral vancomycin is recommended for severe disease. Timely surgical intervention is important in patients who have severe complicated CDI.
    Infections in medicine 01/2009; 26(7):211-220. · 0.20 Impact Factor
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    ABSTRACT: Clostridium difficile infection (CDI) caused by toxigenic strains of C. difficile is primarily a nosocomial infection with increasing prevalence. Stool specimens are typically collected in Cary-Blair transport medium to maximize culture-based detection of common stool pathogens. The goal of this study was to establish an analytically accurate and efficient algorithm for the detection of CDI in our patient population using samples collected in Cary-Blair transport medium. In addition, we wished to determine whether the sensitivity and specificity of PCR was affected by freezing samples before testing. Using 357 specimens, we compared four methods: enzyme immunoassay for the antigen glutamate dehydrogenase (Wampole™ C. DIFF CHEK-60 Assay, GDH), toxin A and B enzyme immunoassay (Remel ProSpecT™ C. difficile Toxin A/B Microplate Assay, Toxin EIA), cell culture cytotoxicity neutralization assay (Bartels™ Cytotoxicity Assay, CT), and real-time PCR targeting the toxin B gene (BD GeneOhm™ Cdiff Assay, PCR). The analytic sensitivity and specificity of each as determined using a combined gold standard were as follows: GDH, 100% and 93.2%; Toxin EIA, 82.9% and 82.9%; CT, 100% and 100%; PCR (performed on frozen specimens) 74.3% and 96.6%; respectively. However, the sensitivity and specificity of PCR improved to 100% when performed on 50 fresh stool samples collected in Cary-Blair. While CT remains a sensitive method for the detection of CDI, GDH offers an excellent initial screening method to rule out CDI. While the performance of each assay did not appear to be affected by collection in Cary-Blair medium, PCR performed better using fresh specimens.
    Infectious disease reports 03/2011; 3(1):e5.
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    ABSTRACT: Background: Clostridium difficile (CD) is considered an important cause of diarrhoea associated with the antimicrobial treatment of infections. The pathogenicity of CD is due to toxins A and B, produced by toxigenic CD strains. Methods: We evaluated 3 methods for detecting CD toxins: the RIDASCREEN® enzyme immunoassay (EIA) (R-Biopharm) – one detecting toxins directly in the stool specimens and another detecting toxins from isolated CD strains – and 2 molecular methods, the illumigene™ loop-mediated isothermal amplification (LAMP) assay (Meridian) and RIDA®GENE polymerase chain reaction (PCR) assay (R-Biopharm), as direct identification methods from stool specimens. Toxigenic culture (TC) was used as the reference method. Results: Altogether 884 stool samples were analyzed, of which 253 (29%) were positive by TC. Six hundred and seventy-two specimens were tested by RIDASCREEN EIA, 430 were tested with the illumigene LAMP assay, and 212 were tested with the RIDA GENE PCR assay. CD toxin A and B antigen tests by EIA were very insensitive, both directly from stool specimens (2 series; 57–61%) and in isolated CD strains (53%); consequently the negative predictive value remained low (84–93% and 91%, respectively). Specificity, however, was very good at 98–100%. The 2 molecular methods detected CD toxin genes excellently and equally, resulting in sensitivities, specificities, and positive and negative predictive values of 98%, 100%, 100%, and 98%, respectively. Conclusions: Both molecular assays were easy to use, rapid, sensitive, and specific for the detection of toxigenic CD strains.
    Scandinavian Journal of Infectious Diseases 12/2012; 45(1). · 1.64 Impact Factor


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