Experimental Pyelonephritis. VII. Evidence on the Mechanisms by Which Obstruction of Urine Flow Enhances Susceptibility to Pyelonephritis ‡

One of the key problems in the pathogenesis of pyelonephritis is to explain how obstruction of urine flow renders the kidney more susceptible to infection. Since urine is a good culture medium, slowing of its excretion doubtless provides opportunity for more luxuriant bacterial multiplication, but there are indications that other consequences of urinary obstruction favor the growth and survival of bacteria in the tissues of the kidney. The purpose of the present communication is to review the existing evidence on this subject, and to report some additional pertinent experiments. The latter include observations on the development of acute pyelonephritis when the urine contained a concentration of antibiotic sufficient to inhibit growth of bacteria, and a comparison of the relative degree of susceptibility conferred by obstructive lesions of different ages.