Acquiescent renal infection.

The relationship between bacterial infection of the renal parenchyma with Escherichia coli and the establishment of pathologic lesions has been investigate experimentally. Infection was established in one kidney and the bacteriologic, pathologic and immunologic features of infection were compared in the pyelonephritic and contralateral unmanipulated kidney. Whereas active bacterial infection was associated with pathologic changes in the pyelonephritic kidney, a poor correlation was found between bacterial growth and the gross pathology and histopathologic changes in the contralateral kidney. The conclusion from these studies is that infection of the kidney is not always associated with pathologic changes. The term "acquiescent infection" has been used to describe this host-parasite relationship in which active, persistent, bacterial infection is not associated with pathologic lesions. Evidence is presented that bacteria in the contralateral unmanipulated kidney are present in the renal parenchyma and that bacterial proliferation can be induced following renal trauma. Activation of infection and bacterial proliferation did not always result in histopathologic damage to the kidney and was not associated with an increase in serum antibody.