Kinetically monitoring the expression of alpha-toxin using an HLA promoterluciferase reporter fusion in Staphylococcus Aureus

Staphylocoocus aureus is an important pathogen and can cause both human and animal infections. The continual emergence of drug resistant, notably methicillin resistant S. aureus isolates from hospitalized patients and in the community, as well as in livestock farms has produced a serious public health burden. The availability of a sensitive approach to monitor temporal gene expression or regulation enables us to elucidate molecular mechanism of resistance and pathogenesis. In this study, we chose bacterial luciferase (LuxABCDE) as a reporter and created a promoter-lux fusion in different S. aureus isolates, determined the transcriptional levels of alpha-toxin gene (hla) using a luminometer, and found that the temporal expression and the intensity of bioluminescence vary in different isolates carrying the same hla promoter-lux reporter. The results indicate that the luciferase-driven bioluminescence reporter provides a powerful tool for temporal examination of gene expression and regulation.