Object:To study in vitro antibacterial activity of prulifloxacin against pathogenic bacteria of respiratory tract and urinary tract infections.Methods:The minimum inhibitory concentration(MIC) of prulifloxacin and levofloxacin against 221 pathogenic bacteria of respiratory tract and urinary tract infections was determined by agar dilution method.Results:MIC50

MIC90 and the susceptible rate of prulifloxacin were≤0.03~1μg/ml

0.5~4μg/ml and 67%~100%

respectively.Those of levofloxacin were 0.125~2μg/ml

0.5~8μg/ml and 61%~100%

respectively.MIC90 of prulifloxacin was half that of levofloxacin against Escherichia coli

Enterobacter cloacae

Pseudomonas aeruginosa and Moraxella catarrhalis.MIC90 of prulifloxacin was equal to that of levofloxacin against Klebsiella pneumoniae

Proteus spp

Staphlococcus epidermidis

Streptococcus pneumoniae and Enterococus faecalis.MIC90 of prulifloxacin was two times that of levofloxacin against Haemophilus influenzae and Staphylococcus aureus.Conclusion:Prulifloxacin had a broad-spectrum antibacterial activity against pathogenic bacteria of respiratory tract and urinary tract infections.