Diagnostic accuracy of the Cepheid GeneXpert vanA/vanB assay ver. 1.0 to detect the vanA and vanB vancomycin resistance genes in Enterococcus from perianal specimens

Erin S Marner; Donna M Wolk; Jeanne Carr; Carolyn Hewitt; Lorraine L Dominguez; Thomas Kovacs; Desiree R Johnson; Randall T Hayden

doi:10.1016/j.diagmicrobio.2010.11.005

Diagnostic accuracy of the Cepheid GeneXpert vanA/vanB assay ver. 1.0 to detect the vanA and vanB vancomycin resistance genes in Enterococcus from perianal specimens

Diagn Microbiol Infect Dis. 2011 Apr;69(4):382-9. doi: 10.1016/j.diagmicrobio.2010.11.005.

Authors

Erin S Marner¹, Donna M Wolk, Jeanne Carr, Carolyn Hewitt, Lorraine L Dominguez, Thomas Kovacs, Desiree R Johnson, Randall T Hayden

Affiliation

¹ University of Arizona, Tucson, AZ 85724-5059, USA.

PMID: 21396533
DOI: 10.1016/j.diagmicrobio.2010.11.005

Abstract

Rapid detection of vancomycin-resistant enterococci (VRE) carriers could be useful to health care facilities to minimize transmission. To that end, we compared the performance of the Cepheid GeneXpert vanA/vanB assay with that of direct and broth-enriched culture methods for detection of VRE from perianal swabs. Enterococci were cultivated on Enterococcosel™ agar with 8 μg/mL vancomycin, Bile Esculin Azide Agar with 6 μg/mL vancomycin, and Bile Esculin Azide Enterococcosel Broth. Compared to the reference standard (combination of direct agar plating, broth-enriched culture, and clinical chart review), the sensitivity, specificity, positive predictive value, and negative predictive value of the vanA/vanB assay were 96.4%, 93.0%, 92.0%, and 96.9%, respectively (n=184). The 95% limit of detection was 100 colony-forming units (CFU)/mL for vanA and 114 CFU/mL for vanB. In summary, the GeneXpert vanA/vanB assay is a rapid and accurate method to identify vanA/vanB-colonized patients for VRE screening programs that use perianal swab specimens.

Publication types

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

MeSH terms

Anal Canal / microbiology*
Bacterial Proteins / genetics*
Bacteriological Techniques / methods*
Carbon-Oxygen Ligases / genetics*
Cell Culture Techniques
Enterococcus / enzymology
Enterococcus / genetics*
Enterococcus / isolation & purification
Gram-Positive Bacterial Infections / diagnosis
Gram-Positive Bacterial Infections / microbiology*
Humans
Molecular Diagnostic Techniques / methods*
Polymerase Chain Reaction
Predictive Value of Tests
Reproducibility of Results
Time Factors

Substances

Bacterial Proteins
VanA ligase, Bacteria
VanB protein, Enterococcus
Carbon-Oxygen Ligases