Efficacy and Nephrotoxicity of Polymyxin B for Carbapenem-resistant Gram-negative Bacilli: A Single-center, Retrospective, Observational Study

OBJECTIVE To analyze the efficacy and renal toxicity of polymyxin B(PMB) in the treatment of carbapenem-resistant gram-negative bacilli(CR-GNB), and to provide scientific basis for the rational use of PMB.

METHODS This retrospective study included adult patients diagnosed with CR-GNB infection between October 1, 2021, and July 31, 2022, who received intravenous PMB therapy for ≥72 h for the first time at The First Affiliated Hospital, Zhejiang University School of Medicine. The patients’ baseline data, clinical efficacy, and acute kidney injury(AKI) were statistically analyzed.

RESULTS After screening, 90 out of 353 patients were included. The CR-GNB infected with PMB therapy was 30.9%(21/68), the 28 d mortality rate was 36.4%(32/88), and the total incidence of AKI was 36.2%(25/69). Subgroup analysis indicated that, PMB bacterial clearance rate(33.3% vs 25.0%), 28 d mortality rate(41.4% vs 26.7%) and AKI incidence rate(44.2% vs 23.1%) in ICU group showed a numerical trend higher than that in the non-ICU group; however, none of these differences reached statistical significance. In the ICU group, PMB treatment was mainly used for carbapenem-resistant Acinetobacter baumannii and respiratory tract infections. Multivariate logistic regression analysis showed that C-reactive protein level before treatment and receiving renal replacement therapy were independent risk factors for 28 d mortality during PMB treatment.

CONCLUSION PMB has limited efficacy in eradicating the pathogen of CR-GNB infection, but it still shows certain efficacy in clinical treatment. The potential nephrotoxicity of PMB should be closely monitored during administration.