The continued emergence
of bacterial resistance has created an
urgent need for new and effective antibacterial agents. Bacterial
type II topoisomerases, such as DNA gyrase and topoisomerase IV (topoIV),
are well-validated targets for antibacterial chemotherapy. The novel
bacterial topoisomerase inhibitors (NBTIs) represent one of the new
promising classes of antibacterial agents. They can inhibit both of
these bacterial targets; however, their potencies differ on the targets
among species, making topoIV probably a primary target of NBTIs in
Gram-negative bacteria. Therefore, it is important to gain an insight
into the NBTIs key structural features that govern the topoIV inhibition.
However, in Gram-positive bacteria, topoIV is also a significant target
for achieving dual-targeting, which in turn contributes to avoiding
bacterial resistance caused by single-target mutations. In this perspective,
we address the structure–activity relationship guidelines for
NBTIs that target the topoIV enzyme in Gram-positive and Gram-negative
bacteria.