Evaluation of penicillin in conjunction with acetohydroxamic acid in treatment of experimental Corynebacterium renale pyelonephritis

Abstract

The therapeutic efficacies of procaine penicillin G and acetohydroxamic acid, when administered alone or in combination, were evaluated in rats with experimentally induced pyelonephritis at 24 h and 4 days after intrabladder inoculation with Corynebacterium renale. Penicillin alone prevented the development of pyelonephritis when administered in a once daily dose of 50 000 units for 5 days beginning within 24 h of infection challenge. However, if therapy was not initiated until the 4th day after induction of infection, pyelonephritis ensued which could not be differentiated from untreated rat pyelonephritis. Acetohydroxamic acid, when administered by itself in a once daily dose of 100 mg for 5 days, was completely ineffective whether therapy was started at 24 h or 4 days after initiation of infection. On the other hand, the combination of penicillin and acetohydroxamic acid prevented progression of pyelonephritic infection and facilitated healing when rat kidneys were examined at 14 and 30 days after initiation of infection. The kidneys of those rats sacrificed at 30 days after cessation of treatment revealed the presence of increased interstitial fibrous connective tissue in the renal medulla suggesting prior damage followed by recovery and repair. In vitro studies on the action of penicillin and acetohydroxamic acid against C. renale revealed no signs of synergism or antagonism.