What is the principal molecular action of quinolones and fluoroquinolones on bacterial DNA replication?

• A. They competitively inhibit bacterial DNA polymerase by mimicking deoxynucleotide triphosphates and are therefore strictly bacteriostatic.
• B. They methylate bacterial DNA, preventing DNA polymerase binding and halting replication without causing breaks.
• C. They bind bacterial topoisomerase/gyrase and block religation of cut DNA, producing lethal double-strand breaks.
• D. They incorporate into DNA as false nucleotides causing chain termination during replication in both bacteria and human cells.

Answer: (C)