In vitro activity of 6 fluoroquinolones against Ureaplasma urealyticum

Objective: To determine the susceptibility of clinical Ureaplasma urealyticum (Uu) isolates to fluoroquinolones and provide experimental data for clinical therapy. Methods:Broth microdilution method was used for susceptibility testing of 88 isolates of Uu to 6 fluoroquinolones. Results:Among 6 fluoroquinolones, sparfloxacin and gatifloxacin were the most active agents against Uu, MIC 50 being 0.25μg/ml and 0.5μg/ml, respectively; with MIC 90 being 4μg/ml for both. Levofloxacin and ofloxacin were less active, MIC 50 being 1μg/ml, 2μg/ml and MIC 90 being 4μg/ml, 8μg/ml, respectively. Norfloxacin and Ciprofloxacin had the least activity against Uu. Conclusions: New fluoroquinolones such as sparfloxacin, levofloxacin and gatifloxacin show greater activity against Uu than the older agents do; Uu is resistant to older fluoroquinolones in varing degree.