Population analysis profiles at 240 h profiling the emergence of resistant subpopulations grown on polymyxin B-containing agar for the regimens shown in Figure 3. PMB, polymyxin B; DOR, doripenem. Control, bacterial subpopulations present at time 0 h (without any treatment); DOR (25 mg/L q8h) monotherapy, DOR traditional monotherapy (fCmax of 25 mg/L every 8 h); PMB (2 mg/L CI) monotherapy, PMB traditional monotherapy (fCss of 2 mg/L administered as a continuous infusion); PMB (5 mg/L CI) monotherapy, fCss of 5 mg/L administered as a continuous infusion; PMB (2 mg/L CI) + DOR Burst (25 mg/L q8h for 24 h), combination of PMB traditional (fCss of 2 mg/L continuous infusion) and DOR ‘burst’ (fCmax of 25 mg/L every 8 h × 3 doses followed by no DOR thereafter); PMB (2 mg/L CI) + DOR (25 mg/L q8h), combination of PMB traditional (fCss of 2 mg/L continuous infusion) and DOR (fCmax of 25 mg/L every 8 h); PMB Burst (2 mg/L CI on day 1) + DOR (25 mg/L q8h), combination of PMB ‘burst’ (fCss of 5 mg/L continuous infusion for 24 h followed by no PMB thereafter) and DOR (fCmax of 25 mg/L every 8 h); PMB Burst (5 mg/L CI on day 1) + DOR (25 mg/L q8h), combination of PMB ‘burst’ (fCss of 2 mg/L continuous infusion for 24 h followed by no PMB thereafter) and DOR (fCmax of 25 mg/L every 8 h); PMB Front-Loading (5 mg/L CI on day 1 then 2 mg/L CI thereafter) + DOR (25 mg/L q8h), combination of PMB ‘front-loading’ (fCss of 5 mg/L continuous infusion for 24 h followed by fCss of 2 mg/L thereafter) and DOR (fCmax of 25 mg/L every 8 h). This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.