[Piperacillin in in vitro-in vivo combination].

Launched two years ago, piperacillin is administered either alone or combined with other antibiotics. Broadening the antibacterial spectrum, looking for synergism and preventing the emergence of resistant mutants constitute a major preoccupation, especially in immunodepressed patients, and an indication for combined antibiotic therapy. The most effective combination, justified by in vitro tests, consists of a beta-lactam antibiotic and an aminoglycoside. In vitro studies have demonstrated an antagonistic effect between two beta-lactam antibiotics, and mutants have been isolated in vivo. The results obtained with the piperacillin-vancomycin combination are not as good as those obtained with previous combinations. The advent of new compounds, such as aztreonam, fluorinated quinolones and beta-lactamase inhibitors offers hopes of excellent results.