<prompt> Mechanism of action of ciprofloxacin in gram negative bacteria:-Inhibition of mycolic acidInhibition of topoisomerase IVInhibition of DNA gyraseInhibition of helicase  <response>: MECHANISM OF FLUOROQUINOLONES FQ In gram negative bacteria, FQ inhibit DNA gyrase by binding to its A subunit and interfere with cutting and resealing function. In gram positive bacteria, FQ inhibit similar enzyme DNA topoisomerase IV. 