Clostridioides difficile PCR Tcdb Cycle Threshold predicts toxin EIA positivity but not severity of infection

Regan Mah; Kerstin Locher; Theodore S Steiner; Aleksandra Stefanovic

doi:10.1016/j.anaerobe.2023.102755

Clostridioides difficile PCR Tcdb Cycle Threshold predicts toxin EIA positivity but not severity of infection

Anaerobe. 2023 Aug:82:102755. doi: 10.1016/j.anaerobe.2023.102755. Epub 2023 Jul 3.

Authors

Regan Mah¹, Kerstin Locher², Theodore S Steiner³, Aleksandra Stefanovic⁴

Affiliations

¹ Faculty of Medicine, University of British Columbia, 899 W 12th Ave, Vancouver, BC V5Z 1M9, Canada. Electronic address: rsmah@ualberta.ca.
² Department of Pathology and Laboratory Medicine, University of British Columbia, Rm. G227 - 2211 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada. Electronic address: kerstin.locher@vch.ca.
³ Division of Infectious Diseases, University of British Columbia, Rm. C328 Heather Pavilion East, VGH 2733 Heather Street, Vancouver, BC, Canada. Electronic address: tsteiner@mail.ubc.ca.
⁴ Division of Medical Microbiology and Virology, St. Paul's Hospital, Providence Room 2150, 1081 Burrard Street, Vancouver, BC V6Z 1Y6, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Providence Room 2150, 1081 Burrard Street, Vancouver, BC V6Z 1Y6, Canada. Electronic address: astefanovic@providencehealth.bc.ca.

PMID: 37406762
DOI: 10.1016/j.anaerobe.2023.102755

Abstract

Background: Diagnosis of Clostridioides difficile Infection (CDI) entails compatible clinical presentation and laboratory findings. We evaluated real-time polymerase chain reaction (qPCR) cycle threshold (C_T) as a predictor for disease severity and TcdB enzyme immunoassay (EIA) results.

Methods: Inpatients or emergency department patients who tested positive for tcdB gene by PCR were evaluated. Patients' stools underwent testing for GDH and TcdA/B by EIA. Medical health records were reviewed for demographic, clinical presentation, laboratory, treatment and outcome data. Severity of CDI was calculated using various severity score indexes.

Results: The median C_T of cases was 32.05 ± 5.45. The optimal cut-off for predicting toxin EIA positivity and severe CDI based on chart review was 32.6 and 29.8, respectively, with the area under the receiver operator characteristics curve (AUC) of 0.74 and 0.60 respectively.

Conclusion: C_T value was an acceptable predictor for EIA toxin but less so for clinical severity. Our study potentially supports a diagnostic algorithm including C_T value to reduce the number of EIA toxin assays performed.

Keywords: Clostridioides difficile; Cycle_threshold; EIA_Toxin; Polymerase_chain_reaction.

MeSH terms

Bacterial Proteins / analysis
Bacterial Proteins / genetics
Bacterial Toxins* / analysis
Bacterial Toxins* / genetics
Clostridioides / genetics
Clostridioides difficile* / genetics
Clostridium Infections* / diagnosis
Feces / chemistry
Humans
Immunoenzyme Techniques
Real-Time Polymerase Chain Reaction

Substances

Bacterial Toxins
Bacterial Proteins