Fig. 2. Piperacillin and tazobactam concentrations measured by LC-MS in supernatants from community cultures with and without plasmid, or sterile medium, after 0, 6 and 24 h of incubation.

Concentrations are shown relative to the mean 0 h concentration in the control treatment (see Methods). Bars represent means (n = 3) and “BDL” signifies below detection limit for the compounds.