[Relation of the chelating property of nitroxoline, the surface hydrophobicity and the inhibition of bacterial adherence].

Nitroxoline or 5-nitro-8-hydroxyquinoline acts by a chelating effect with various metallic divalent cations. The chelating property of nitroxoline has been proposed as an hypothesis to explain the activity of this drug, at sub-MIC, on the inhibition of bacterial adherence. Nitroxoline (MIC/4) does not inhibit fimbriae synthesis but its antibacterial activity on E. coli 387 (MS/MS) was decreased by the addition of MgCl2 (50 mM) and CaCl2 (10 mM). The chelating effect of nitroxoline is mainly due to the presence of the nitrous radical in position 5. Nitroxoline would act at the outer membrane level of the bacterial cell-wall by a chelating effect preferentially with Mg++ than Ca++. Furthermore, nitroxoline (MIC/8) increases the bacterial surface hydrophobicity of E. coli 38 in contrast to EDTA (MIC/4). The both products inhibit the bacterial adherence to cells with the same manner.