Effects of subminimal inhibitory concentrations of ampicillin, chloramphenicol, and nitrofurantoin on the attachment of Escherichia coli to human uroepithelial cells in vitro.

An in vitro system with epithelial cells of the human urinary tract and Escherichia coli isolated from the urine of pateints with acute pyelonephritis was used for tests of the effect of antibacterial agents on bacterial adhesion. E. coli treated with subminimal inhibitory amounts of ampicillin attached less than untreated control bacteria. Subminimal inhibitory amounts of chloramphenicol and nitrofurantoin had no effect on adhesion of the 15 strains of E. coli tested. The combination of bacterial pretreatment with ampicillin and addition of antibodies to the adhesion test tube decreased adhesion more than did either treatment separately.