Performance of the BD GeneOhmTM MRSA Test

Link: Performance of the BD GeneOhmTM MRSA Test Before and, During High-Volume Clinical Use -- Paule et al., 10.1128/JCM.00670-07 -- Journal of Clinical Microbiology.

We evaluated use of the BD GeneOhmTM MRSA (BD Diagnostics, San Diego, CA) real-time PCR assay for the detection of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization. The initial evaluation consisted of 403 paired nasal swabs and was done using the kit provided specimen preparation and an in-house lysis method that was specifically developed to accommodate large volume testing using a minimal amount of personnel time. One swab was placed into an achromopeptidase (ACP) lysis solution and the other was used for culture, then prepared according to the kit protocol. PCR was performed on both lysates with results compared to culture. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the PCR assay was 98%, 96%, 77%, and 99.7% with the kit lysate and 98%, 95%, 75% and 99.7% with the ACP lysate (p = NS). The second evaluation was done after implementation of all-admission surveillance using PCR with ACP lysis and a sampling of 1107 PCR negative samples and 215 PCR positive samples that were confirmed by culture. The results of this sampling showed a NPV of 99.9% and a PPV of 73.5% (prevalence = 6%), which were consistent with our initial findings. The BD GeneOhmTM MRSA assay is an accurate and rapid way to detect MRSA nasal colonization. When dealing with large specimen numbers, the ACP lysis method offers easier processing without negatively affecting the PCR assay sensitivity or specificity.