[In vitro studies with piperacillin. Effectiveness against enterobacteriaceae and pseudomonas aeruginosa compared to other antibiotics (author's transl)].

The in vitro activity of piperacillin, a new semisynthetic penicillin was compared with the inhibitory effect of other broad-spectrum penicillins and beta-lactamase stable cephalosporins. The examination was carried out by agar diffusion test with 1699 gram-negative strains. The antibacterial activity of piperacillin was generally superior to that of the other penicillins. Less than one per cent. of pseudomonas aeruginosa strains tested was resistant against piperacillin. Only klebsiella spp. showed a higher sensitivity against cefoxitin and cefuroxime.