quinolone antibiotic

Quinolone antibiotics constitute a large group of broad-spectrum bacteriocidals that share a bicyclic core structure related to the substance 4-quinolone. They are used in human and veterinary medicine to treat bacterial infections, as well as in animal husbandry, specifically poultry production.

Quinolone antibiotics are classified into four generations based on their spectrum of activity and chemical modifications. The first-generation quinolones, such as nalidixic acid, primarily target Gram-negative bacteria and are mainly used for urinary tract infections. Second-generation quinolones introduced fluorine atoms into their structure, creating fluoroquinolones, which significantly expanded their antibacterial activity to include some Gram-positive bacteria. Third-generation fluoroquinolones further improved Gram-positive coverage, while fourth-generation fluoroquinolones offer broad-spectrum activity, including anaerobic bacteria.