Scarring as a factor affecting the eradication of microorganisms from the kidney in pyelonephritis.

The inability of antimicrobial agents to penetrate scarred renal tissue may explain some therapeutic failures. We examined the effect of scarring on antimicrobial therapy by using a unique animal model in which both kidneys were infected to the same degree but only one kidney was scarred. Scar formation could not explain the failure of ampicillin or nitrofurantoin to eradicate renal infection, but co-trimoxazole was less effective in the presence of tissue damage and scar formation than in their absence.