Background: Escherichia coli is the bacterium most commonly isolated from the urine of patients with urinary tract infection (UTI). Recurrent episodes of UTI lead to renal interstitial scarring. In interstitial fibrosis and scarring, infiltration of mononuclear cells has been reported to play a key role.
Materials and methods: We evaluated the effect of two strains of E. coli--the pathogenic BH-5 and the plasmidless, nonfimbriated HB-101-on human monocyte and murine macrophage apoptosis.
Results: E. coli BH-5 enhanced apoptosis in a time- and dose-dependent manner. 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 its virulence and play a role in renal interstitial scarring.