Document Detail

Assessment of Clostridium difficile infections by quantitative detection of tcdB toxin by use of a real-time cell analysis system.
MedLine Citation:
PMID:  20720023     Owner:  NLM     Status:  MEDLINE    
We explored the use of a real-time cell analysis (RTCA) system for the assessment of Clostridium difficile toxins in human stool specimens by monitoring the dynamic responses of the HS27 cells to tcdB toxins. The C. difficile toxin caused cytotoxic effects on the cells, which resulted in a dose-dependent and time-dependent decrease in cell impedance. The RTCA assay possessed an analytical sensitivity of 0.2 ng/ml for C. difficile toxin B with no cross-reactions with other enterotoxins, nontoxigenic C. difficile, or other Clostridum species. Clinical validation was performed on 300 consecutively collected stool specimens from patients with suspected C. difficile infection (CDI). Each stool specimen was tested in parallel by a real-time PCR assay (PCR), a dual glutamate dehydrogenase and toxin A/B enzyme immunoassay (EIA), and the RTCA assay. In comparison to a reference standard in a combination of the three assays, the RTCA had a specificity of 99.6% and a sensitivity of 87.5% (28 of 32), which was higher than the EIA result (P = 0.005) but lower than the PCR result (P = 0.057). In addition, the RTCA assay allowed for quantification of toxin protein concentration in a given specimen. Among RTCA-positive specimens collected prior to treatment with metronidazole and/or vancomycin, a significant correlation between toxin protein concentrations and clinical CDI severities was observed (R(2) = 0.732, P = 0.0004). Toxin concentrations after treatment (0.89 ng/ml) were significantly lower than those prior to the treatment (15.68 ng/ml, Wilcoxon P = 0.01). The study demonstrates that the RTCA assay provides a functional tool for the potential assessment of C. difficile infections.
Alex B Ryder; Ying Huang; Haijing Li; Min Zheng; Xiaobo Wang; Charles W Stratton; Xiao Xu; Yi-Wei Tang
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Publication Detail:
Type:  Comparative Study; Evaluation Studies; Journal Article     Date:  2010-08-18
Journal Detail:
Title:  Journal of clinical microbiology     Volume:  48     ISSN:  1098-660X     ISO Abbreviation:  J. Clin. Microbiol.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-10-29     Completed Date:  2011-02-10     Revised Date:  2013-05-28    
Medline Journal Info:
Nlm Unique ID:  7505564     Medline TA:  J Clin Microbiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4129-34     Citation Subset:  IM    
Departments of Pathology and Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-5310, USA.
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MeSH Terms
Bacterial Proteins / toxicity*
Bacterial Toxins / toxicity*
Bacteriological Techniques / methods*
Cells, Cultured
Clostridium Infections / diagnosis*
Clostridium difficile / pathogenicity*
Feces / chemistry
Fibroblasts / drug effects,  physiology
Sensitivity and Specificity
Reg. No./Substance:
0/Bacterial Proteins; 0/Bacterial Toxins; 0/toxB protein, Clostridium difficile

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