[N-Formimidoyl-thienamycin in Animal Studies].

The beta-lactam antibiotic thienamycin is rather unstable and is metabolized in man by renal dehydropeptidase-I. The derivatives of the antibiotic, especially N-formimidoyl-thienamycin (MK-0787) are reported to be more resistant. The antibacterial activity of N-formimidoyl-thienamycin was tested by means of the infection- and therapy model of the acute, occlusive pyelonephritis in rats. Cefotaxime was used as control agent. Even with a low dosage a clear anti-bacterial activity was proved with the E. coli- as well as especially with the Pseudomonas pyelonephritis. In our tests N-formimidoyl-thienamycin was more potent than cefotaxime.