Real-time cellular analysis coupled with a specimen enrichment accurately detects and quantifies clostridium difficile toxins in stool Journal Article
| Authors: | Huang, B.; Jin, D.; Zhang, J.; Sun, J. Y.; Wang, X.; Stiles, J.; Xu, X.; Kamboj, M.; Babady, N. E.; Tang, Y. W. |
| Article Title: | Real-time cellular analysis coupled with a specimen enrichment accurately detects and quantifies clostridium difficile toxins in stool |
| Abstract: | We describe here the use of an immunomagnetic separation enrichment process coupled with a modified real-time cellular analysis (RTCA) system (RTCA version 2) for the detection of C. difficile toxin (CDT) in stool. The limit of CDT detection by RTCA version 2 was 0.12 ng/ml. Among the consecutively collected 401 diarrheal stool specimens, 53 (13.2%) were toxin-producing C. difficile strains by quantitative toxigenic culture (qTC); bacterial loads ranged from 3.00 × 101 to 3.69 × 106 CFU/ml. The RTCA version 2 method detected CDT in 51 samples, resulting in a sensitivity of 96.2%, a specificity of 99.7%, and positive and negative predictive values of 98.1% and 99.4%, respectively. The positive step time ranged from 1.43 to 35.85 h, with <24 h for 80% of the samples. The CDT concentrations in stool samples determined by RTCA version 2 correlated with toxigenic C. difficile bacterial load (R2 = 0.554, P = 0.00002) by qTC as well as the threshold cycle (R2 = 0.343, P = 0.014) by real-time PCR. A statistically significant correlation between the CDT concentrations and the clinical severity of CDI was observed (P = 0.015). The sensitivity of the RTCA version 2 assay for the detection of functional toxins in stool specimens was significantly improved when the immunomagnetic separation enrichment process was incorporated. More than 80% positive results can be obtained within 24 h. The stool specimen CDT concentration derived using the RTCA version 2 assay correlates with clinical severity and may be used as a marker for monitoring the status of CDI. Copyright © 2014, American Society for Microbiology. All Rights Reserved. |
| Keywords: | adolescent; adult; child; controlled study; aged; unclassified drug; major clinical study; diarrhea; nonhuman; diagnostic accuracy; sensitivity and specificity; disease severity; quantitative analysis; intermethod comparison; immunoassay; real time polymerase chain reaction; clostridium difficile infection; vancomycin; bacterium culture; metronidazole; predictive value; feces analysis; diagnostic test accuracy study; limit of detection; diagnostic kit; bacterial load; bacterial toxin; human; male; female; priority journal; article; clostridium difficile toxin; fidaxomicin; immunomagnetic separation enrichment; polymerase chain reaction system; real time cellular analysis; real time cellular analysis system; toxin analysis |
| Journal Title: | Journal of Clinical Microbiology |
| Volume: | 52 |
| Issue: | 4 |
| ISSN: | 0095-1137 |
| Publisher: | American Society for Microbiology |
| Date Published: | 2014-04-01 |
| Start Page: | 1105 |
| End Page: | 1111 |
| Language: | English |
| DOI: | 10.1128/jcm.02601-13 |
| PROVIDER: | scopus |
| PUBMED: | 24452160 |
| PMCID: | PMC3993479 |
| DOI/URL: | |
| Notes: | Cited By (since 1996):1 -- Export Date: 1 May 2014 -- CODEN: JCMID -- Source: Scopus |
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