Prospective, multicenter evaluation of the BD GeneOhm VanR assay for direct, rapid detection of vancomycin-resistant Enterococcus species in perianal and rectal specimens

Am J Clin Pathol. 2010 Aug;134(2):219-26. doi: 10.1309/AJCPR1K0QFLBJSNH.

Abstract

The BD GeneOhm VanR assay (BD Diagnostics, San Diego, CA), a qualitative test for the rapid detection of vancomycin-resistant enterococci (VRE) from rectal and/or perianal swabs, combines integrated nucleic acid extraction and automated polymerase chain reaction for the detection of vanA and/or vanB gene sequences. We studied 1,027 perianal and rectal swab specimens from 3 geographically distinct US sites (prevalence rates, 13.1%-25.8%). Direct swab specimens were tested by the assay and compared with direct culture. The sensitivity, specificity, and positive and negative predictive values of the assay were 93.2%, 81.9%, 54.4%, and 98.1%, respectively. The specificity was limited largely due to false-positives in the vanB portion of the assay. Specificity with perianal swabs was significantly greater than with rectal swabs, 87.1% vs 74.7%, respectively (P < .0001). When used only to detect resistance conferred by vanA, the assay was 88.3% (158/179) sensitive and 95.8% (802/837) specific, with positive and negative predictive values of 81.9% and 97.4%, respectively. The assay is a simple, rapid, and acceptable method for screening for VRE in a variety of populations in which vanA is the predominant genotype. Samples positive for the vanB genotype should be confirmed by culture owing to the apparent high number of false-positive results.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anal Canal / microbiology*
  • Bacterial Proteins / isolation & purification
  • Carbon-Oxygen Ligases / isolation & purification
  • DNA, Bacterial / analysis
  • Enterococcus / isolation & purification*
  • False Positive Reactions
  • Female
  • Humans
  • Male
  • Polymerase Chain Reaction / methods*
  • Prevalence
  • Reagent Kits, Diagnostic*
  • Rectum / microbiology*
  • Sensitivity and Specificity
  • Vancomycin Resistance*

Substances

  • Bacterial Proteins
  • DNA, Bacterial
  • Reagent Kits, Diagnostic
  • VanA ligase, Bacteria
  • VanB protein, Enterococcus
  • Carbon-Oxygen Ligases