Comparative colistin sulfate vs. polymyxin B in patients with carbapenem-resistant organism bloodstream infections.

OBJECTIVES

To compare the efficacy and safety of colistin sulfate (CS) vs. polymyxin B (PMB) sulfate in treating patients with carbapenem-resistant organism bloodstream infections (CRO-BSI).

METHODS

We conducted a retrospective cohort study of adult patients with CRO-BSI (January 2022-June 2025) treated with intravenous CS or PMB. The primary outcome was 28-d all-cause mortality. Secondary outcomes were clinical treatment response, microbiological clearance and acute kidney injury (AKI). We used 1:1 propensity-score matching to balance baseline covariates and performed multivariate Cox regression to adjust for potential confounders.

RESULTS

After matching (60 patients per group), 28-d mortality was similar between CS and PMB (33% vs. 30%; P = 0.70). Clinical effectiveness (35% vs. 28%) and microbiological clearance (68% vs. 62%) did not differ significantly (all P > 0.4). In contrast, AKI was less frequent with CS (13% vs. 28%; P = 0.043). Multivariate Cox analysis confirmed no significant mortality difference (adjusted HR for CS vs. PMB, 0.68; 95% CI 0.33-1.40; P = 0.293).

CONCLUSIONS

CS and PMB were equally effective in treating patients with CRO-BSI, but the CS group experienced a lower rate of AKI.