Abstract: The present invention relates to methods and compositions for the modulation of bacterial topoisomerase enzymes within bacterial cells. More specifically, the present invention relates to bacterial assays wherein the levels of bacterial topoisomerase enzymes or the levels of target sites within the enzymes are varied within bacterial test strains in order to screen for compounds that target, i.e., interact with the topoisomerase enzymes, causing DNA damage and hence, bacterial growth inhibition and/or cell death. The present methods and compositions are useful for the identification and characterization of novel therapeutic antibacterial compounds.