What mechanism of action does ciprofloxacin utilize to exert its antibacterial effect?

Ciprofloxacin exerts its antibacterial effect primarily through the inhibition of DNA gyrase, an essential enzyme in bacterial DNA replication. DNA gyrase is a type II topoisomerase that introduces negative supercoils into DNA, which is crucial for the relaxation of supercoiled DNA ahead of the replication fork. By interfering with this process, ciprofloxacin prevents proper DNA replication and transcription, ultimately leading to bacterial cell death.

The specificity of ciprofloxacin for bacterial DNA gyrase is key to its effectiveness as an antibiotic, as this target is not present in human cells, allowing for selective toxicity against bacteria. This mechanism is central to the action of fluoroquinolones, the class of antibiotics to which ciprofloxacin belongs, making it particularly useful in treating various bacterial infections.