Experimental Pyelonephritis. IX. The Bacteriological Course and Morphological Consequences of Staphylococcal Pyelonephritis in the Rat, with Consideration of the Specificity of the Pathological Changes Observed

Although coliform bacteria are the organisms most commonly recovered from the urine of patients with pyelonephritis, they seldom cause infection in the absence of some kind of renal injury.' These bacteria are not suitable, therefore, for experiments designed to study alterations of structure and function attributable to infection alone. For these purposes it would seem preferable to employ microorganisms capable of establishing infection in normal kidneys, e.g. staphylococci. The present series of experiments was carried out in the rat since renal physiology and pathology have been studied extensively in this animal. Other investigations of staphylococcal pyelonephritis have been performed in mice or rabbits.2"'" Such species were considered unsatisfactory for these investigations since they are not well suited for studies of renal physiology and since the mortality is appreciable following production of extensive pyelonephritis with virulent staphylococci. This report describes the bacteriological and morphological course of staphylococcal pyelonephritis in normal rats. The alterations in renal function produced by this infection will be described in the paper which follows.