Experimental pyelonephritis in dogs.

Both E. coli and S. aureus were simultaneously injected into the left renal arteries of 55 female dogs. The arteries were occluded for 10 minutes prior to the injection and 10 minutes after. The renal veins were occluded during the injection and for 10 minutes after. Ten animals did not survive longer than 24 hours. Ten of 45 developed neither renal lesions nor bacteriuria; of the remaining 35 which did, five were killed on each of the second, seventh and fourteenth days, and their renal lesions were assessed. Eighteen of the remaining 2 which developed bacteriuria were killed 3 to 12 weeks following surgery when bacteria could no longer be recovered from the urine. Only two dogs had persistent bacteriuria 12 weeks after surgery. All animals which developed bacteriuria had gross lesions in the left kidney but not the right. Naturally occurring renal lesions were found in 17 of 78 random-source dogs at laparotomy. E. coli was cultured from the urine of five of these dogs but not from the kidneys. These lesions were morphologically similar to experimental ones. It is concluded that with this method renal lesions similar to spontaneous ones can be produced, but care must be taken to exclude the relatively large percentage of random-source dogs with naturally occurring lesions from any study. Various forms of infectious nephritis have been reported to be among the commonest diseases of dogs (1, 2). The successful production of chronic pyelonephritis in dogs depends on a variety of factors in addition to injecting bacteria into either the renal artery or ureter. Thus, ureteral obstruction, renal anoxia and reduced pulse pressure increased the susceptibility to renal infection (3, 4, 6, 7, 8). Our laboratory has been concerned with the production of experimental pyelonephritis in dogs so that the efficacy of various treatments could be studied. The present work was undertaken to standardize methods of producing the disease and to compare experimental renal lesions with naturally occurring ones.