[Antibacterial activity of the combination of cefoperazone piperacillin]

The effect of the combination cefoperazone plus piperacillin was tested against 131 clinical isolates of gram-positive and gram-negative bacteria by checkerboard titration and by determining the serum bactericidal activity. The interaction was synergistic against 9% of the strains in vitro and partially synergistic against 48%. In the serum bactericidal tests bactericidal titers higher than 1:8 were obtained with the combination one hour after administration. No antagonism was observed either in the in vitro tests or in tests of serum bactericidal activity.