[Inhibition of bacterial adhesion of uropathogenic Escherichia coli strains by the urine of patients treated with nitroxoline].

The present study evaluates the effects of sub-inhibitory concentrations of nitroxoline, (oxyquinoline derivative) widely used in the treatment of uncomplicated, urinary tract infections, on the adherence of uropathogenic strains of Escherichia coli. These bacterial strains showed mannose sensitive and/or mannose resistant hemagglutinating activity (HA). In the presence of nitroxoline and at sub-MIC concentrations, inhibition of adherence is 90% (MIC/4), 87% (MIC/8), and 70% (MIC/16), whatever HA's are expressed by the E. coli strains. The inhibitory effect on adherence is also observed in the urine after oral administration of 400 mg of nitroxoline. The concentrations of nitroxoline in the urine are determined by microbiological assay (anti-bacterial activity) and by physico-chemical assay (total nitroxoline and free nitroxoline). The percentages of inhibition are related to the concentrations of free and conjugated nitroxoline. For a 1/16 dilution of urine, the inhibitory effect is 70% and 87% respectively 1 h 30 and 2 h 30 after oral administration of nitroxoline. After 5 h, a similar inhibitory effect is observed for a 1/2 dilution of urine. These results justify the performance of a clinical trial on the prophylaxis of recurrent urinary tract infections by nitroxoline.