[Effects of subinhibitory concentrations of pefloxacine on hemolysin production and adherence of urinary Escherichia coli].

The in vitro effect of subinhibitory concentrations of pefloxacin on E. coli's production of hemolysin and adherence to eucaryotic cells was studied. Six uropathogenic E. coli strains, with mannose-resistant and/or mannose-sensitive adhesins were tested. All strains produced an alpha-hemolysin and were susceptible to pefloxacin (0.125 less than or equal to MIC less than or equal to 0.250 mg/l). The effect on hemolysin production was studied using microtitration plates to determine the concentration inhibiting 50% of E. coli's hemolytic activity. The inhibition of adhesion was tested following adhesion of E. coli to uroepithelial cells. Sub-MICs of pefloxacin strongly inhibited the production of alpha-hemolysin and adhesion of E. coli regardless of adhesin type. A correlation between the inhibition of hemolysin production and the inhibition of adhesion to uroepithelial cells was found for four E. coli strains.