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The BD GeneOhm™ VanR Assay is a qualitative in vitro test for the rapid detection of vancomycin-resistance (vanA and vanB) genes directly from perianal or rectal swabs. The BD GeneOhm™ VanR Assay detects the presence of the vanA and vanB genes that can be associated with vancomycin-resistant enterococci (VRE). The assay is performed on an automated real-time PCR instrument with perianal or rectal swabs from individuals at risk for VRE colonization. The BD GeneOhm™ VanR Assay can be used as an aid to identify, prevent and control vancomycin-resistant colonization in healthcare settings. The BD GeneOhm™ VanR Assay is not intended to diagnose VRE infections nor to guide or monitor treatment for VRE infections. Concomitant cultures are necessary to recover organisms for epidemiological typing, susceptibility testing and for further confirmatory identification.

Following specimen lysis, the vanA and vanB genetic targets, if present, are amplified. Amplification of the Internal Control (IC), a DNA fragment of 294-bp including a 254-bp sequence not found in VRE, will also take place unless PCR inhibitory substances are present. The amplified DNA targets are detected with molecular beacon probes, hairpin-forming single-stranded oligonucleotides labelled at one end with a quencher and at the other end with a fluorescent reporter dye (fluorophore). In the absence of target, the fluorescence is quenched. In the presence of target, the hairpin structure opens upon beacon/target hybridization, resulting in emission of fluorescence. For the detection of the vanA amplicon, the molecular beacon probe contains the fluorophore FAM at the 5' end and the nonfluorescent quencher moiety DABCYL at the opposite 3' end of the oligonucleotide. For the detection of the vanB amplicon, the molecular beacon probe contains the fluorophore Texas Red at the 5' end and the quencher DABCYL at the 3' end. For the detection of the IC amplicon, the molecular beacon probe contains the fluorophore TET at the 5' end and the quencher DABCYL at the 3' end. Each beacon-target hybrid fluoresces at a wavelength characteristic of the fluorophore used in the particular molecular beacon probe. The amount of fluorescence at any given cycle, or following cycling, depends on the amount of specific amplicon present at that time. The SmartCycler® software simultaneously monitors the fluorescence emitted by each molecular beacon probe, interprets all data, and provides a final result at the end of the cycling program.