Ciprofloxacine is a synthetic fluoroquinolone that is antibiotic with a very wide range of effects. The mechanism that leads to the bactericidal effect is partially unexplained, known the gyrase inhibiting effect. The gyrase of bacteria is responsible for DNA replication and cell division. Ciprofloxacin works mainly in gram-negative germs and especially in Pseudomonas aeruginosa. It is listed as a reserve antibiotic in GI infections. The drug was developed by Bayer.