The bactericidal activity of gemifloxacin (SB-265805).

The bactericidal activity and mechanisms of action of the new fluoroquinolone gemifloxacin were investigated against the laboratory strains Escherichia coli KL16, Staphylococcus aureus E3T and Streptococcus pneumoniae C3LN4. Gemifloxacin was found to be highly bactericidal against these bacteria, producing a biphasic dose-response curve typical of the fluoroquinolones. This novel fluoroquinolone was more bactericidal than all other fluoroquinolones so far tested (ciprofloxacin, ofloxacin, enoxacin, lomefloxacin, levofloxacin, clinafloxacin, trovafloxacin, DV-7751 and sitafloxacin) against S. aureus and was more bactericidal than most other fluoroquinolones against E. coli or Str. pneumoniae. These data show gemifloxacin to be an improved member of the fluoroquinolone class of antibacterial agents.