A new multiplex PCR assay for the simultaneous detection of vancomycin-resistant enterococci from rectal swabs

Summary 

Objectives

This study describes the diagnostic performance of a recently available multiplex PCR-based kit for the simultaneous detection and identification of Enterococcus faecium, Enterococcus faecalis, vanA, vanB, vanC1 and vanC2/C3 genes, directly from rectal swabs constituting the most complete existing molecular assay currently available.

Methods

The diagnostic performance of this assay was evaluated by a multicenter study involving three independent public hospitals and consisted in the analysis of 187 rectal swabs from patients at high risk for vancomycin-resistant enterococci colonization.

Results

When bacteria culture was used as the gold standard, the sensitivity, specificity, positive and negative predicted values for the assay were 96.8%, 76.0%, 67.7% and 97.9%, respectively. When a composite reference standard consisting of culture and DNA sequencing of PCR products was used as the gold standard, the sensitivity, specificity, positive and negative predicted values for the PCR-based assay were 97.8%, 96.9%, 96.7% and 97.9%, respectively.

Conclusions

Based on these results, we conclude that this assay is considerably more sensitive than traditional microbiological methods for detecting vancomycin-resistant enterococci from rectal swabs. It is also much faster than culture. We believe that the implementation of this assay in routine clinical laboratories could help to reduce hospital-acquired vancomycin-resistant enterococci infections.

Keywords: Vancomycin-resistant enterococci, Molecular biology assay, Multiplex PCR, In vitro diagnostics, Control of hospital-acquired infections