An electron microscopic study of the interaction between vesical epitherlium and E. Coli.

Interaction between rat bladder epithelium and Escherichia coli was observed using the transmission electron microscope. As a first step, the bacterial cell coat attaches to the cell coat of the luminal membrane. Then, the luminal membrane enfolds to envelope the bacterium and take it within the cytoplasm. The unit membranes covering the bacteria are destroyed and some of these bacteria are found to be deformed and probably dead in the cytoplasm. Finally, the superficial epithelial cells invaded by many bacteria are collapsed and desquamated into urine. However, these epithelia show a rather prompt recovery and form the normal three layers within 24 hr after inoculation. This experiment suggests one of the defense mechanisms of the vesical epithelium againts E. coli. It is likely that the onset of clinical cystitis may be prevented by the same mechanism during the occasional bacterial invasion of the bladder.