Xpert MRSA/SA SSTI

The Xpert MRSA/SA SSTI is an automated in vitro diagnostic test that detects Staphylococcus aureus (SA) and methicillin-resistant S. aureus (MRSA) DNA from skin and soft tissue infection swabs using real-time PCR. Results are provided in approximately 62 minutes and are intended to aid clinical diagnosis in conjunction with culture and other laboratory data, not to monitor treatment.

The device uses the same nucleic acid amplification technology (real-time PCR with specific primers and TaqMan probes targeting spa, mecA, and SCCmec sequences) as the predicate, with identical test automation, single-use disposable cartridge format, and internal controls (Sample Processing Control and Probe Check Control). The only technical difference is approximately 12 minutes longer turnaround time (62 vs. 50 minutes) due to instrument-specific thermal cycling profiles.

Not stated in this summary.

The modified device performs the same assay with identical technology and targets on the new GeneXpert Infinity System platform (versus the original Dx System). Verification studies showed 100% agreement in reportable results and no statistically significant differences in Ct values between Dx and Infinity instruments, demonstrating equivalent performance across the GeneXpert Instrument Systems family. The differences (expanded indications to include all GeneXpert platforms and slightly longer run time) do not raise new questions of safety or effectiveness because the underlying scientific technology and detection method remain fundamentally unchanged.