In-vitro and in-vivo antibacterial activity of fleroxacin, a new fluorinated quinolone.

The in-vitro and in-vivo antibacterial activities of fleroxacin were compared with those of other new quinolones including NY-198. Fleroxacin showed potent activity against most members of the Enterobacteriaceae, Neisseria gonorrhoeae and Haemophilus influenzae, and good activity against Pseudomonas aeruginosa and staphylococci. Against these bacteria, the activity of fleroxacin was roughly comparable to that of norfloxacin, enoxacin, NY-198, and ofloxacin, but slightly less than that of ciprofloxacin. Fleroxacin strongly inhibited DNA supercoiling activity of DNA gyrase purified from Escherichia coli which may explain its high antibacterial activity. The protective effects of a single oral dose of fleroxacin in mice were greater than those of norfloxacin and comparable to or greater than that of ciprofloxacin, ofloxacin and NY-198 against systemic infections with Staphylococcus aureus, Esch. coli and Ps. aeruginosa, and Serratia marcescens.