title: Levofloxacin in vitro activity: results from an international comparative study with ofloxacin and ciprofloxacin.
abstract: Levofloxacin, the S-(-)-isomer of ofloxacin, was compared to ofloxacin and ciprofloxacin against > 6000 recent clinical isolates of Gram-positive and Gram-negative bacteria from six different countries. This international multicenter study demonstrated a high level of antibacterial activity of levofloxacin against all the members of Enterobacteriaceae [minimum inhibitory concentration (MIC)50s, < or = 0.03 to 0.12 mg/L] except Providencia rettgeri (MIC50, 2 mg/L), and Providencia stuartii (MIC50, 1 mg/L). Oxacillin-susceptible staphylococci (MIC50s, 0.12 to 0.25 mg/L), enterococci (MIC50s, 0.5 to 2 mg/L), and streptococci (MIC50s, 0.5 mg/L) were also susceptible to levofloxacin, but most isolates of oxacillin-resistant staphylococci had MICs of > or = 4 mg/L. Levofloxacin was also active against non-enteric Gram-negative bacilli, including Acinetobacter species (MIC50s, < or = 0.03 to 1 mg/L), Pseudomonas species (MIC50s, 0.5 to 1 mg/L) and Xanthomonas maltophilia (MIC50, 0.5 mg/L). Overall, levofloxacin inhibited 50% and 90% of all the tested strains at the concentrations of 0.12 and 4 mg/L, respectively. The activity of levofloxacin was generally two-fold greater than ofloxacin and equal to or slightly less potent than ciprofloxacin.
authors.affiliation: Department of Laboratory Medicine, Kumamoto University Medical School, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Yamane
authors.forename: R N
authors.initials: RN
authors.lastname: Jones
authors.forename: R
authors.initials: R
authors.lastname: Frei
authors.forename: D J
authors.initials: DJ
authors.lastname: Hoban
authors.forename: A C
authors.initials: AC
authors.lastname: Pignatari
authors.forename: F
authors.initials: F
authors.lastname: Marco
mesh_terms: D001208:Asia; D002939:Ciprofloxacin / Q000494:pharmacology*; D005060:Europe; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D006801:Humans; D064704:Levofloxacin; D008826:Microbial Sensitivity Tests; D009656:North America; D015242:Ofloxacin / Q000031:analogs & derivatives / Q000494:pharmacology*; D013020:South America
chemical_list: D002939:Ciprofloxacin; D064704:Levofloxacin; D015242:Ofloxacin