Final answer:
Quinolone and fluoroquinolone antibiotics function by inhibiting the bacterial DNA gyrase and topoisomerase IV, enzymes necessary for DNA unwinding and replication.
Step-by-step explanation:
Quinolone and fluoroquinolone antibiotics target and inhibit the function of bacterial DNA gyrase and topoisomerase IV. These are critical enzymes that facilitate the unwinding of DNA, which is a necessary step for DNA replication. By blocking this process, quinolones prevent bacteria from replicating their DNA, thus inhibiting bacterial growth and reproduction.
DNA gyrase, in particular, is a type II topoisomerase that relieves strain while double-stranded DNA is being unwound, which is essential for processes such as transcription and replication. Fluoroquinolones, being potent inhibitors of these enzymes, show effective antibacterial activity, especially against Gram-negative bacteria, but also some Gram-positive and anaerobic bacteria in later generations of the drug.
The enhancements made to the original quinolone structure have augmented their potency and broadened their spectrum of activity resulting in fluoroquinolones like ciprofloxacin and levofloxacin, which are widely used in treating various infections