Abstract
The effect of subinhibitory concentrations of ciproftoxacin, lomeftoxacin, norfloxacin, ofloxacin, and sparfloxacin on urease activity and on cell surface hydrophobicity of urea-splitting bacteria was examined. Quinolones at 0.5 MICs demonstrated variable effects on bacterialurease activity. Norfloxacin inhibited enzyme activity in Proteus vulgaris and Proteus mirabilis, while other quinolones had no effects. In Morganella morgan ii, sparfloxacin and ciprofloxacin enhanced urease activity, particularly at the initial phase ofgrowth. All quinolones tested showed no marked effect on urease activity by Providencia rettgeri. Quinolones at the same concentrations induced an increase in the cell surface hydrophobicity, which was strain-dependent. There was no correlation between urease inhibition and cell surface hydrophobicity. Inhibition of urease activity by quinolones, in addition to their antibacterial activities, may prevent the progression of urinary tissue damage and stone formation.