Polymyxin Including Therapy Versus Colistin Including Therapy In The Therapy Of Carbapenem-Resistant Gram-Negative Infections: A Retrospective Matched Cohort Study

Abstract

BACKGROUND-AIM: In this retrospective matched cohort study, we aimed to compare the clinical outcomes of polymyxin b (PMXB) including therapy receiving cases with colistin receiving cases on culture-proven carbapenem-resistant Gram-negative infections (CPCRGNI). METHOD: This study was performed at a 1800+ bedded tertiary-care hospital. Adult patients with culture proven CRCRGNI (bacteremia, pneumonia etc.) treated with PMXB or colistin including regimens between August 2016 and October 2023 were included.Matching was performed as one PMXB matched to minimum 1 or 2 colistin whenever possible according to the clinical sample infecting strain was yielded (pneumonia vs. pneumonia etc.) RESULTS: A total of 210 patients(72 (36,00%)female, aged 60,26±17,44),79 cases in PMXB group and 131 cases in colistin group diagnosed with CRCRGNI.Sixty strains had colistin susceptibility data and 56(93.3%) strains were sensitive to colistin.OMM in overall cohorts (56.96% in PMXB 58,01% in colistin p:0.881), overall acute kidney injury, overall microbiological success, and overall clinical success at the end of therapy did not differ significantly(Table). OMM in the overall UTI(3/6 50,0% vs 9/12 75,0% p0.288) and pneumonia subgroups(23/35 65,71% vs 46/70 65,71% p:1) were also similar. Both treatment group OMM were similar in Acinetobacter and Klebsiella subgroups, but significantly lower with PMXB in Pseudomonas subgroup (Table).OMM was also similar within known colistin-sensitive cases(34/56 -60,71%) vs others(77/154- 50,0%)(p:0.168). Interestingly, OMM in overall UTI(OMM 3/6-50% vs 7/12-58.3%) was not significantly different, but in favor of PMXB. CONCLUSIONS: PMXB including therapy resulted nonsignificntly less OMM than colistin cohort and significantly less OMM in Pseudomonas subgroup. Nephrotoxicity was nonsignificantly less in PMXB cohort.

Keywords

• polymyxin
• multidrug resistance
• carbapenem resistance