INTERNALIZATION OF ESCHERICHIA-COLI INTO HUMAN KIDNEY EPITHELIAL-CELLS - COMPARISON OF FECAL AND PYELONEPHRITIS-ASSOCIATED STRAINS

A gentamicin survival assay, using primary human renal epithelial cell s and Escherichia coli strains isolated from the feces of asymptomatic individuals and from the urine or blood of patients with acute pyelon ephritis, was used to investigate bacterial. internalization as a mode l for renal parenchymal invasion in pyelonephritis. E. coli strains, r egardless of their origin, efficiently entered into human renal epithe lial cells, a process inhibited by cytochalasin D. While the percentag e of survival of nonhemolytic: pyelonephritis isolates did not differ from that of fecal isolates, survival of hemolytic pyelonephritis stra ins was lower than that of nonhemolytic strains, perhaps as a conseque nce of the greater cytotoxicity of hemolytic strains. There was no evi dence of intracellular multiplication of E. coli. These results demons trate that human renal epithelial cells are capable of efficient uptak e of E. coli regardless of the source of the bacteria.