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Comparison of Efficacy and Safety of Colistimethate Sodium and Polymyxin B in the Treatment of Bloodstream Infection Caused by Carbapenem-Resistant Gram-Negative Bacteria: A Retrospective Study

Year: 2025

Type: article

Abstract: Background: This study aimed to compare the efficacy and safety of colistimethate sodium (CMS) and polymyxin B (PMB) in treating carbapenem-resistant Gram-negative bacteria (CR-GNB)-induced bloodstream infection (BSI) based on real-world data. While international studies on CMS and PMB have yielded conflicting results, there is a lack of direct comparative data from Chinese cohorts, where the pathogen distribution may influence outcomes. Methods: A retrospective analysis was conducted on 373 Chinese patients with CR-GNB-induced BSI who received CMS-containing therapy (n=132) or PMB-containing therapy (n=241) between Dec 2021 and Dec 2023. Propensity score matching was used to balance the two groups at a ratio of 1:2. The primary outcome was clinical success. The secondary outcomes included inpatient days, in-hospital mortality, 28-day all-cause mortality, and incidence of adverse events. Statistical analysis was performed with Wilcoxon rank sum test, Student’s t -test, chi-square test, and Fisher’s exact test as appropriate. Results: In this cohort, Acinetobacter baumannii was the predominant pathogen (53.4%). No significant differences were observed in efficacy outcomes between the two groups (p> 0.05). For safety, the difference in hyperpigmentation incidences between the two groups was statistically significant (CMS vs PMB: 0.0% vs 6.36%, p =0.04). Incidences of hypersensitivity, neurotoxicity, and nephrotoxicity were similar between groups (p> 0.05). A longer treatment course (> 12 days), while associated with a higher incidence of hyperpigmentation, was linked to significantly improved clinical outcomes, including higher success rate, reduced in-hospital mortality, and lower 28-day all-cause mortality (p< 0.05). Conclusion: This study provides the first large, real-world comparative evidence from a Chinese cohort with CR-GNB BSIs. In this setting, CMS and PMB demonstrated comparable efficacy. The critical difference lay in the safety profile, with CMS associated with a markedly lower incidence of hyperpigmentation. This finding provides a tangible basis for antibiotic stewardship, positioning CMS as a valuable first-line polymyxin option. Keywords: bloodstream infection, colistimethate sodium, carbapenem-resistant Gram-negative bacteria, polymyxin B

Source: Infection and Drug Resistance

DOI: 10.2147/idr.s555233