In this project, a light-emitting bacterium will be exposed to a series of commonly used antibiotic drugs and elucidate their specific role that affect recA/RAD51 gene, which engages in DNA recombination, as a cell cycle checkpoint. The mechanism by which bacteria respond to DNA-interacting drugs is by their potential to damage cellular DNA, which will be probed by specific induction of recA promoter coupled lux-genes against drugs that emit photons. These emitted photons by bacteria will illuminate the medium and the resulting DNA-damage-specific concomitant emission of photons will therefore be sensitively measured through a photomultiplier tube (PMT). This process will allow high-throughput screening for genotoxicity and carcinogenicity of a series of DNA-interacting drugs using previously programmed bioluminescent bacteria. The results obtained from this project will provide valuable information on drugs’ safety from exhibiting genotoxicity and carcinogenicity side-effects, which is currently limited.