Escherichia coli promotes macrophage apoptosis

Background: Escherichia coli is the bacterium most commonly isolated from t he urine of patients with urinary tract infection (UTI), Recurrent episodes of Un lead to renal interstitial scarring. In interstitial fibrosis and sc arring, infiltration of mononuclear cells has been reported to play a key r ole. Materials and Methods: We evaluated the effect of two strains of E. coli-th e pathogenic BH-5 and the plasmidless, nonfimbriated HB-101-on human monocy te and murine macrophage apoptosis, Results: E, coli BH-5 enhanced apoptosis in a time- and dose-dependent mann er. It also promoted necrosis in a time- and dose-dependent manner. Strain HB-101 promoted monocyte apoptosis in a dose-dependent manner. However, the magnitude of HB-101-induced monocyte apoptosis was lower than BH-5-induced macrophage apoptosis, Conclusion: The ability of E. coli to induce apoptosis may contribute to it s virulence and play a role in renal interstitial scarring.