Comparative activities of norfloxacin and fleroxacin in experimental infections due to Salmonella typhimurium and Escherichia coli.

Norfloxacin and fleroxacin displayed similar in-vitro activity against test strains of Escherichia coli (MIC 0.06 mg/l) and Salmonella typhimurium (0.125 mg/l). Septicaemic infection of mice with E. coli could be almost cured by quinolones but not by ampicillin. Fleroxacin was more potent than norfloxacin. Infection of mice with S. typhimurium was much more difficult to treat. In spite of higher doses the bacterial counts remained at a considerable level. Again, fleroxacin was more active in vivo than norfloxacin.