Which antibiotic listed is known to inhibit DNA synthesis?

The antibiotic that inhibits DNA synthesis is trimethoprim. It works by targeting the bacterial enzyme dihydrofolate reductase, which is essential for the synthesis of tetrahydrofolate, a precursor necessary for DNA and RNA synthesis. By inhibiting this enzyme, trimethoprim effectively disrupts nucleic acid production, leading to a halt in bacterial growth.

Fusidic acid, on the other hand, primarily inhibits protein synthesis by interfering with the elongation factor G during the translation process. Ceftriaxone is a broad-spectrum cephalosporin antibiotic that disrupts bacterial cell wall synthesis, contributing to its bactericidal activity, but it does not directly inhibit DNA synthesis. Rifampicin is associated with the inhibition of RNA synthesis by binding to bacterial RNA polymerase, thus preventing transcription rather than affecting DNA synthesis directly.