A fluoroquinolone antibiotic widely used as an antimicrobial and immunomodulatory agent; functions by inhibiting DNA A fluoroquinolone antibiotic widely used as an antimicrobial and immunomodulatory agent; functions by inhibiting DNA gyrase (a type II topoisomerase) and topoisomerase IV, the enzymes responsible for negative supercoiling of chromosomes and DNA strand separation, thus blocking initiation of bacterial replication.