Performance characteristics of the Cepheid Xpert vanA assay for rapid identification of patients at high risk for carriage of vancomycin-resistant Enterococci

J Clin Microbiol. 2012 Nov;50(11):3659-63. doi: 10.1128/JCM.01776-12. Epub 2012 Sep 12.

Abstract

We compared the performance characteristics of culture and the Cepheid Xpert vanA assay for routine surveillance of vancomycin-resistant enterococci (VRE) from rectal swabs in patients at high risk for VRE carriage. The Cepheid Xpert vanA assay had a limit of detection of 100 CFU/ml and correctly detected 101 well-characterized clinical VRE isolates with no cross-reactivity in 27 non-VRE and related culture isolates. The clinical sensitivity, specificity, positive predictive value, and negative predictive value of the Xpert vanA PCR assay were 100%, 96.9%, 91.3%, and 100%, respectively, when tested on 300 consecutively collected rectal swabs. This assay provides excellent predictive values for prompt identification of VRE-colonized patients in hospitals with relatively high rates of VRE carriage.

Publication types

  • Evaluation Study

MeSH terms

  • Bacterial Proteins / genetics*
  • Bacteriological Techniques / methods*
  • Carbon-Oxygen Ligases / genetics*
  • Carrier State / diagnosis*
  • Carrier State / microbiology
  • Enterococcus / genetics*
  • Enterococcus / isolation & purification
  • Feces / microbiology
  • Gram-Positive Bacterial Infections / diagnosis*
  • Gram-Positive Bacterial Infections / microbiology
  • Humans
  • Predictive Value of Tests
  • Reagent Kits, Diagnostic*
  • Sensitivity and Specificity
  • Vancomycin Resistance*

Substances

  • Bacterial Proteins
  • Reagent Kits, Diagnostic
  • VanA ligase, Bacteria
  • Carbon-Oxygen Ligases