GatifloxacinS1340

Gatifloxacin has somewhat better in vitro activity against M. tuberculosis than moxifloxacin, and both are much more active than levofloxacin. Gatifloxacin is against M. tuberculosis ATCC 35801 with MICs of 0.125 μg/mL. ^[1] Gatifloxacin possesses potent inhibitory activities against bacterial type II topoisomerases (50% inhibitory concentration [IC50] = 13.8 mg/mL for S. aureus topoisomerase IV; IC50 = 0.109 mg/mL for E. coli DNA gyrase) but the lowest activity against HeLa cell topoisomerase II (IC50 = 265 mg/mL) among the quinolones tested. ^[2] Gatifloxacin is synergic with the beta-lactams piperacillin, cefepime and meropenem, and with gentamicin against some drug-resistant pathogens. ^[3] Gatifloxacin, an 8-methoxyfluoroquinolone, inhibits a staphylococcal efflux pump. Gatifloxacin combined with Ciprofloxacinplus shows synergy by the Etest method for 6 (19%) of the 31 P. aeruginosa isolates using a summation fractional inhibitory concentration of < or = 0.5 for synergy. ^[4] Gatifloxacin is two-fold less potent than ciprofloxacin, and the same as or two-fold more potent than ofloxacin against Enterobacteriaceae. Gatifloxacin is highly potent (MIC90s, 0.03-0.06 mg/L) against Haemophilus influenzae, Legionella spp., Helicobacter pylori and has at least eight-fold better anti-chlamydial and anti-mycoplasma potency (gatifloxacin MIC90s, 0.13 mg/L). ^[5]