effect of subminimal inhibitory concentrations of antibiotics on adhesion of Escherichia coli

The influence of subminimal inhibitory concentrations of gentamicin, pipracillin and ciprofloxacin on hemagglutination of ten Escherichia coli isolates curried P-adhesion fimbriae were studies. Gentamicin rendered the bacteria totally to non hemagglutining pipracillin decrease hemagglutination ability to 40% at the concentrations of the MIC12.5 MIC25 and MIC50. Whereas ciprofloxacin had no effect on adhesion at the concentration of the MIC12.5 and MIC25 but the hemagglutination ability were decreased to 50% at MIC50. In titration, pipracillin slightly reduced the hemagglutination capability compared with the control. In contrast, ciproftoxacin markly increased the hemagglutimtion capability with all treatments. These results suggest, that the greatest effect of antibiotics at the DNA translation stage, by interfering with formation of fimbriae. In addition to that, no correlation were observed between hemagglutination ability and MICs values of piprecillin or ciprofloxacin as well as between fimbriae formation and the two kinds of antibiotics

Role of Tamm-Horsfall protein in the binding and in vivo phagocytosis of type 1 fimbriated Escherichia coli by mouse peritoneal macrophages

Tamm-Horsfall glycoprotein (THP) contains manno-oligosaccharides that are recognized by type 1 fimbriae (F1) of Escherichia coli. In the present study, we examined the in vivo phagocytic activity of mouse peritoneal macrophages after treatment of bacteria with THP. At low THP concentrations (12.5 æg/ml and 50 æg/ml) no significant difference was observed in the phagocytosis of E. coli F1+. However, at high THP concentrations (500 æg/ml and 1250 æg/ml) we obtained a reduction of bacterial phagocytosis by mouse peritoneal macrophages