Adherence of E. coli to bladder epithelia in compromised mice and plasma endotoxin level

Abstract

The role of bacterial adherence in association with complicated urinary tract infections (UTI) and the correlation between bacterial adherence and plasma endotoxin (ET) levels were experimentally investigated by using mouse UTI models. Mice with foreign bodies induced in the bladder or voiding dysfunction were more susceptible to UTI than untreated mice. But diabetic or granulocytopenic mice were little susceptible to UTI in comparison with other two models. Adherence activities of 6 strains of E. coli to mice bladder epithelia in the 4 compromised models showed no difference when compared with those in normal control. Binding patterns of 8 kinds of lectins and mouse uromucoid polyclonal antibody to the mice bladder epithelia in compromised models appeared to be almost the same as those in the normal bladder epithelia. These results suggested that the reason for the susceptibility to UTI in the compromised mice was not necessarily explained based on the increased adherence of E. coli due to qualitative or quantitative changes in receptors on the bladder mucosa. Impairment of other host defense mechanisms may be considered in this regard. Three strains of E. coli expressing type 1 pili adhered to the bladder epithelia in greater numbers in vivo than non piliated strains. E. coli No. 113 strain expressing both type 1 and p pili appeared to be the most virulent in vivo among all 6 strains. Plasma ET levels increased 6 to 24 hours after inoculation of 2 strains of E. coli expressing only type 1 pili or p pili, while a little increase in the levels was observed in mice inoculated with non piliated E. coli. Bacterial adherence to the bladder epithelia may play an important role for the increase in ET levels.