Two Decades of Successful SAR-Grounded Stories of the Novel Bacterial Topoisomerase Inhibitors (NBTIs)

The emergence of bacterial resistance against life-saving medicines has forced the scientific community and pharmaceutical industry to take actions in the quest for novel antibacterials. These should not only overcome the existing bacterial resistance but also provide at least interim effective protection against emerging bacterial infections. Research into DNA gyrase and topoisomerase IV inhibitors has become a particular focus, with the description of a new class of bacterial topoisomerase type II inhibitors known as "novel bacterial topoisomerase inhibitors", NBTIs. Elucidation of the key structural modifications incorporated into these inhibitors and the impact these can have on their general physicochemical properties are detailed in this review. This defines novel bacterial topoisomerase inhibitors with promising antibacterial activities and potencies, which thus represent one potential example of the future "drugs for bad bugs", as identified by the World Health Organization.