[Pivampicillin and ampicillin in experimental E. coli pyelonephritis].

The antimicrobiol activity of 6-[D(--)-alpha-aminophenylacetamido]-penicillanic acid-(pivaloyloxymethyl)-ester (privampicillin) was tested in comparison to ampicillin during the acute ascending pyelonephritis of the rat caused by E. coli. Two groups of rats were treated with different drug concentrations; group I:3 times 70 mg/kg/day pivampicillin and 3 times 50 mg/kg/day ampicillin, group II: 3 times 70 mg/kg/day pivampicillin and 3 times 150 mg/kg/day ampicillin; controls were inoculated three times daily with 1.0 ml physiological saline. A higher activity of pivampicillin was found in the first group as proved by bacterial counting in the left and the right renal parenchyma as well as in the urine. In the second group the efficacy of ampicillin was increased.