Experimental pyelonephritis. 13. On the ability of water diuresis to induce susceptibility to E. coli bacteriuria in the normal rat.

There is considerable evidence in man to indicate that bacteria ascend from the bladder to the kidney within the lumen of the ureter, thereby accounting for the principal pathway by which bacteria reach the kidney to produce pyelonephritis.`8 Although much is known about factors that permit the establishment of bacteria infection in the kidney, very little is known about the circumstances that permit bacteria to persist in the bladder urine in the absence of underlying kidney infection. The disappearance of large numbers of bacteria instilled within the normal bladder is rapid and efficient.`6 During the course of experiments designed to test the effect of water diuresis on unilateral pyelonephritis, it was noticed that bacteria were commonly found in the opposite kidney of animals drinking large amounts of fluid and only rarely in animals on a normal water intake. It appeared that water diuresis facilitated the spread of bacteria within the urinary system. Studies were undertaken, therefore, to investigate the effect of water diuresis on bacteria placed within the bladder lumen. The present report describes the outcome of these experiments. The experimental animals were male Sprague-Dawley rats weighing 250-350 grams. The test microorganism has been used in this laboratory for many years and the culture techniques and quantitative bacteriological techniques have all been described previously.' In brief, the inoculum employed was an appropriate dilution in saline of a four and one-half hour broth culture of E. coli. Bacterial viable units were enumerated by serial dilution and pour plate techniques. Inoculation of bacteria into the lumen of the dome of the bladder was carried out after NembutallO anesthesia, through a mid-line abdominal incision. The bladder was punctured with a 27-gauge needle and its contents aspirated prior * Associate Professor of Medicine.