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Clostridioides difficile Toxin B PCR Cycle Threshold as a Predictor of Toxin Testing in Stool Specimens from Hospitalized Adults

Lee, Sean and Nanda, Neha and Yamaguchi, Kenichiro and Lee, Yelim and She, Rosemary C. (2022) Clostridioides difficile Toxin B PCR Cycle Threshold as a Predictor of Toxin Testing in Stool Specimens from Hospitalized Adults. Antibiotics, 11 (5). Art. No. 576. ISSN 2079-6382. PMCID PMC9137712. doi:10.3390/antibiotics11050576.

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Rapid, accurate detection of Clostridioides difficile toxin may potentially be predicted by toxin B PCR cycle threshold (tcdB Cₜ). We investigated the validity of this approach in an inpatient adult population. Patients who tested positive by C. difficile PCR (Cepheid GeneXpert) from December 2016 to October 2020 (n = 368) at a tertiary medical center were included. All stool samples were further tested by rapid glutamate dehydrogenase (GDH)/toxin B EIA and cell cytotoxin neutralization assay (CCNA). Receiver operating characteristic curves were analyzed. The area under the curve for tcdB Cₜ predicting toxin result by EIA was 0.795 (95% confidence interval (CI) 0.747–0.843) and by CCNA was 0.771 (95% CI 0.720–0.822). The Youden Cₜ cutoff for CCNA was ≤27.8 cycles (sensitivity 65.0%, specificity 77.2%). For specimens with Cₜ ≤ 25.0 cycles (n = 115), CCNA toxin was positive in >90%. The negative predictive value of tcdB Cₜ for CCNA was no greater than 80% regardless of cutoff chosen. In summary, very low Cₜ values (≤25.0) could have limited value as a rapid indicator of positive toxin status by CCNA in our patient population. A broad distribution of Cₜ values for toxin-negative and toxin-positive specimens precluded more robust prediction. Additional data are needed before broader application of Cₜ values from qualitatively designed assays to clinical laboratory reporting.

Item Type:Article
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URLURL TypeDescription CentralArticle
Nanda, Neha0000-0002-2919-7316
Lee, Yelim0000-0002-9943-1796
Additional Information:© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( Received: 1 April 2022 / Revised: 19 April 2022 / Accepted: 20 April 2022 / Published: 26 April 2022. (This article belongs to the Special Issue Clostridioides difficile Infection, 2nd Volume) This research received no external funding. The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board of University of Southern California (Protocol HS-16-00402, approved July 2016). Informed Consent Statement. Patient consent was waived due to the study involving no more than minimal risk to subjects and the determination that the waiver would not adversely affect the rights and welfare of subjects. Data Availability Statement. The data presented in this study are available in the Supplementary Materials. The authors declare no conflict of interest.
Subject Keywords:neutralization assay; toxin immunoassay; receiver operating characteristic curve
Issue or Number:5
PubMed Central ID:PMC9137712
Record Number:CaltechAUTHORS:20220428-901560000
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Official Citation:Lee, Sean, Neha Nanda, Kenichiro Yamaguchi, Yelim Lee, and Rosemary C. She. 2022. "Clostridioides difficile Toxin B PCR Cycle Threshold as a Predictor of Toxin Testing in Stool Specimens from Hospitalized Adults" Antibiotics 11, no. 5: 576.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:114519
Deposited By: George Porter
Deposited On:28 Apr 2022 22:23
Last Modified:31 May 2022 18:20

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