Resistance to ciprofloxacin is due to:

Ref: Goodman & Gillman's 13th ed. P 1016* Ciprofloxacin is one of the fluoroquinolones along with norfloxacin, ofloxacin, levofloxacin, spartloxacin, etc.* MOA of quinolones: The quinolone antibiotics target bacterial DNA gyrase and topoisomerase IV.* The quinolones inhibit gyrase-mediated DNA supercoiling at concentrations that correlate well with those required to inhibit bacterial growth.* Mutations of the gene that encodes the A subunit of the gyrase can confer resistance to these drugs.