Enhancement of 5-fluorouracil uptake into the bacterial cell by piperacillin.

The antibacterial activity of 5-fluorouracil, an antineoplastic agent, was found to be enhanced by piperacillin, a beta-lactam antibiotic, resulting in a synergism. It was considered that the synergism was caused by an increase of 5-fluorouracil uptake into the bacterial cell. On the other hand, amount of piperacillin bound to penicillin binding protein (PBP) did not change when 5-fluorouracil was added. The morphological change of the cell was due to the 5-fluorouracil when synergism appeared between 5-fluorouracil and piperacillin.