Procedures
CR-GNB infection
The time from the diagnosis of CR-GNB infection to entering the trial and receiving polymyxin B treatment should not exceed 48 h. In the high-dose (HD) group, patients received 150 mg of polymyxin B (Shanghai First Biochemical Pharmaceutical Co., Ltd.) intravenously as a loading dose and 75 mg every 12 h as an initial maintenance dose, while in the low-dose (LD) group, patients received 100 mg of polymyxin B intravenously as an initial loading dose and 50 mg every 12 h as an initial maintenance dose. For TDM, blood samples were withdrawn from all dosages during the second and seventh dosages. Two blood samples were collected immediately before the infusion (2 mL, CBefore analysis, the supernatant collected from blood samples was stored at − 80 °C. The plasma concentrations of polymyxin B, B1 and B2, were determined using a validated ultra-performance liquid chromatography-tandem mass spectrometry in our hospital laboratory, and the plasma concentration of polymyxin B was the sum of the above two polypeptides [The limited sampling strategies of AUCIf the ssAUC