Performance comparison of the cobas Liat and Cepheid GeneXpert systems for Clostridium difficile detection

PLoS One. 2018 Jul 24;13(7):e0200498. doi: 10.1371/journal.pone.0200498. eCollection 2018.

Abstract

Clostridium difficile infection (CDI) is a high burden and significant cause of healthcare-acquired infectious diarrhea in the United States (US). Timely and accurate diagnosis of CDI enables the rapid initiation of antibiotic therapy and infection control policies to minimize disease transmission. Polymerase chain reaction (PCR) assays have become a preferred modality for diagnosing CDI in the US. The cobas Liat Cdiff PCR test is a novel assay that can be performed on-demand for hospital-based testing with a rapid 20-minute turnaround time from specimen collection to result reporting. We compared the clinical performance of the cobas Liat Cdiff test to the previously introduced Xpert C. difficile/Epi test; both tests are FDA-cleared PCR assays that detect the toxin B (tcdB) gene of C. difficile. Prospectively collected and remnant stool specimens from 310 patients with suspected CDI were obtained for analysis. The cobas Liat Cdiff and Xpert PCR tests showed an overall percent agreement of 97.4% (302/310; 95% CI: 95.0-98.9). Low bacterial burdens of toxigenic C. difficile, indicated by significantly delayed PCR cycle threshold (Ct) values, explained most of the discordance. Positive and negative percent agreement of the cobas Liat Cdiff test compared to the Xpert PCR test were 94.5% (52/55) and 98.0% (250/255), respectively. The clinical performance of the cobas Liat Cdiff test, combined with its simplicity of use and rapid result reporting, provides a reliable option for clinical laboratory use.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Toxins / genetics
  • Clostridioides difficile / genetics
  • Clostridioides difficile / isolation & purification*
  • Clostridium Infections / diagnosis*
  • Diagnostic Tests, Routine*
  • Enterotoxins / genetics
  • Feces / microbiology*
  • Humans
  • Molecular Diagnostic Techniques*
  • Polymerase Chain Reaction
  • Prospective Studies
  • Sensitivity and Specificity

Substances

  • Bacterial Proteins
  • Bacterial Toxins
  • Enterotoxins

Grants and funding

Roche Molecular Systems, Inc. provided support in the form of salaries for selected authors [SC, ST, SKG, and JJS]. An F. Hoffman-La Roche Grant was awarded to Paul A Granato and Glen Hansen. Roche Molecular Systems, Inc. did not play a role in data collection, but played a supporting role in the study design, data analysis, decision to publish, and preparation of the manuscript. The specific roles of each author are articulated in the 'author contributions' section.