Faculty Collaboration Database

Evaluation of Copan FecalSwab as Specimen Type for Use in Xpert C. difficile Assay. J Clin Microbiol 2017 Oct;55(10):3123-3129

Date

08/11/2017

Pubmed ID

28794179

Pubmed Central ID

PMC5625397

DOI

10.1128/JCM.00369-17

Scopus ID

2-s2.0-85030127876 (requires institutional sign-in at Scopus site)   8 Citations

Abstract

Liquid-based microbiology (LBM) devices incorporating flocked swabs and preservation medium ease transport of specimens and improve specimen yield compared to traditional fiber wound swabs; however, the performance of LBM collection devices has not been evaluated in many molecular assays. It is unclear how the differences in matrix and specimen loading with an LBM device will affect test performance compared to traditional collection devices. The purpose of this study was to evaluate the performance of specimens collected in FecalSwab transport medium (Copan Diagnostics, Murrieta, CA) compared to unpreserved stool using the Cepheid Xpert C. difficile assay (Cepheid, Sunnyvale, CA). Results equivalent to unpreserved stool samples were obtained when 400 μl of FecalSwab-preserved stool was employed in the Xpert assay. The positive and negative percent agreement of specimens inoculated with FecalSwab medium (n = 281) was 97.0% (95% confidence interval [CI], 90.9 to 96.4%) and 99.4% (95% CI, 96.4 to 99.9%), respectively, compared to reference results obtained using unpreserved stool. Throughout this study, only four discrepant results occurred when comparing preserved specimens to unpreserved stool specimens in the Xpert C. difficile PCR assay. Post discrepant analysis, using the BD MAX Cdiff assay, the specificity and sensitivity both increased to 100%. The high positive and negative percent agreements observed in this study suggest that stool preserved in FecalSwab media yields equivalent results to using unpreserved stool when tested on the Xpert C. difficile assay, allowing laboratories to adopt this liquid-based microbiology collection device.

Author List

Mashock MJ, Faron ML, Buchan BW, Ledeboer NA

Authors

Blake W. Buchan PhD Professor in the Pathology department at Medical College of Wisconsin
Nathan A. Ledeboer PhD Vice Chair, Professor in the Pathology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Bacterial Toxins
Clostridium Infections
Enterotoxins
Feces
Humans
Molecular Diagnostic Techniques
Preservation, Biological
Sensitivity and Specificity
Specimen Handling