The quinolones are a family of synthetic
Chemical synthesis
In chemistry, chemical synthesis is purposeful execution of chemical reactions to get a product, or several products. This happens by physical and chemical manipulations usually involving one or more reactions...

 broad-spectrum antibiotic
Broad-spectrum antibiotic
The term broad-spectrum antibiotic refers to an antibiotic that acts against a wide range of disease-causing bacteria. A broad-spectrum antibiotic acts against both Gram-positive and Gram-negative bacteria, in contrast to a narrow-spectrum antibiotic, which is effective against specific families of...

s. The term quinolone(s) refers to potent synthetic chemotherapeutic antibacterials.

The first generation of the quinolones begins with the introduction of nalidixic acid
Nalidixic acid
Nalidixic acid is the first of the synthetic quinolone antibiotics...

 in 1962 for treatment of urinary tract infections in humans. Nalidixic acid was discovered by George Lesher and coworkers in a distillate during an attempt at chloroquine synthesis.

They prevent bacterial DNA from unwinding and duplicating.