Abstract: Abstract: Objective　To investigate the clinical efficacy of polymyxin B based combination therapy on patients with carbapenem-resistant gram-negative bacterial (CR-GNB) sepsis. Methods　Clinical data of 48 patients with sepsis who used polymyxin B as the basis for combination therapy of CR-GNB infection were retrospectively analyzed. (1) According to the time from specimen collecting for inspection to the start of the use of polymyxin B, patients were divided into the early group (≤7 days, n=30) and the delayed group (＞7 days, n=18). (2) According to the duration of polymyxin B therapy, patients were divided into the ≤ 7 days group (n=16) and the ＞7 days group (n=32). (3) According to the different combination of polymyxin B-based therapy, patients were divided into the tegacyclin group (n=23), the carbapenem group (n=9) and the other drug groups (piperacillin tazobactam, cefoperazone sulbactam, ciprofloxacin and etimicin, n=16). The total bacterial clearance rate, effective rate and 28-d mortality were compared between groups. Results (1) The total bacterial clearance rate (76.7% vs. 44.4%, χ2=5.107, P＜0.05) and the efficacy rate (73.3% vs. 44.4%, χ2=4.006, P＜0.05) after therapy were higher in the early group than those in the delayed group. There was no significant difference in the 28-day mortality between the two groups (30.0% vs. 38.9%, χ2=0.400, P＞0.05). The total bacterial clearance rate (78.1% vs. 37.5%, χ2=7.696, P＜0.01), efficacy rate (75.0% vs. 37.5%, χ2= 6.400, P＜0.05) and 28-day mortality (21.9% vs. 56.3%, χ2=5.672, P＜0.05) were significantly improved in the therapy duration ＞7-day group compared with the therapy duration ≤ 7-day group. (3) In the combination therapy of polymyxin B, total bacterial clearance rate (69.6% vs. 66.7% vs. 56.3%, χ2=0.823), efficacy rate (69.6% vs. 55.6% vs. 56.3%, χ2=1.051) and 28-day mortality (26.1% vs. 33.3% vs. 43.8%, χ2=1.390) showed no significant difference between the tegacyclin group, the carbapenem group and the other drug groups (all P＞0.05). Conclusion　Polymyxin B should be used in combination with other anti-infective drugs in the early stage and sufficient course of therapy for patients with CR-GNB infected sepsis.

Key words: sepsis, polymyxin B, carbapenem-resistant Gram-negative bacteria, combination therapy, clinical efficacy