Antibiotic therapy is our major frontline treatment against bacterial related infectious diseases. A greater understanding of factors that can affect antibiotic efficacy is a critical step in order to improve the therapy. Using the quinolone family as drug models, we investigate how environmental and genetic variation can change the sensitivity profiles of bacterial cells. Bacterial lethality induced by the quinolone drugs occurs through the formation of DNA double stranded breaks. However, the exact mechanism by which those drug-induced DNA breaks form is incompletely understood. The precise characterization of the DNA damage induced by this drug family will allow us to understand quinolone activity at a more systemic level.