In vitro activity of ceftolozane/tazobactam in combination with other classes of antibacterial agents

The synergy observed for some antibacterial combinations in this study supplements the currently available information for combination therapy and may suggest new directions for treating challenging cases. Some synergistic effects may be attributed, at least in part, to the ESBL-inhibitory activity of tazobactam, although this remains to be proven. The mechanisms of the other synergistic interactions observed also require further elucidation. Ceftolozane/tazobactam did not adversely affect the activity of, and was not affected by, other antibacterial agents given concurrently. In vivo studies will be needed to substantiate these results and to determine their clinical relevance.