Structural features of new quinolones and relationship to antibacterial activity against Gram-positive bacteria.

A major recent focus of quinolone antibacterials has been the development of agents with enhanced activity against Gram-positive bacteria. The extensive research efforts have enabled a better definition of the structural features of quinolones that offer the best combination of clinical efficacy and reduced resistance selection in Gram-positive bacteria. This review considers the structural features of new quinolones and relationship to antibacterial activity against Gram-positive bacteria, while trying to position them in the context of recent and possible future advances based on an understanding of their chemical structure and how these impact on target specificity, avoidance of efflux and prevention of emergence of quinolone-resistant mutants in Gram-positive bacteria.