Abstract: Aim To study in vitro the antibacterial activity of domestic sparfloxacin (SPLX) and compare it with other four quinolones including lomefloxacin (LMLX), ciprof lox acin (CPLX), ofloxacin(OFLX) and enox acin(ENX).Methods Minimal inhibitory concentrations(MIC) were determined by means of agar disk dilution method.The susceptibility was defined acco rding to NCCLs.Results SPLX was the most active one in the quinolones against all tested st rains. Its MIC₉₀ was less or equal to 2 mg·L^-1, while the MIC₉₀ of LMLX、CPLX、OFLX and ENX were 16、 16、16 and 32 mg·L^-1, respecti rely.The geomet ric means of MIC (MIC_g) of SPLX (0.179 mg·L^-1) were significant lower than MIC_g of LMLX、OFLX and ENX and slightly lower than that of CPLX.The susceptible rate of G⁺ cocci was 100%, significantly higher than that of controlled quinolones.Conclusion The antibacterial spectrum of SPLX is wider and the activity against clinical isolates is higher than that of other quinolones.

Key words: sparfloxacin, antibacterial activity in vitro