The Cepheid Xpert® MRSA/SA Blood Culture test is widely used for rapid molecular identification of Staphylococcus aureus directly from positive blood cultures with suggestive microscopy, and for upfront characterisation of methicillin susceptibility (MSSA) or resistance (MRSA). The assay targets proprietary sequences of the spa gene, a highly conserved genetic element present in virtually all S. aureus . It also incorporates targets for the mecA and staphylococcal cassette chromosome mec ( SCCmec ) genes, to differentiate MSSA and MRSA.
Kaur et al. (Sun,) studied this question.