The Efficacy and Tolerability of Colistin Versus Non-Colistin Antimicrobial Regimens Among Hospitalized COVID-19 Patients with Multidrug-Resistant Bacterial Superinfection: An Observational Multicenter Study.

Background and Objectives: Bacterial infections amongst COVID-19 patients could be associated with worsened outcomes. This study aimed to investigate the efficacy of colistin antibiotic in multidrug-resistant (MDR) Gram-negative (-ve) secondary bacterial infections among hospitalized COVID-19 patients. Materials and Methods: In this multicentered retrospective study, we analyzed data from the medical records of 116 patients diagnosed with COVID-19 infection and secondary Gram-negative MDR bacterial respiratory infections. Results: We compared those assigned to colistin versus non-colistin-based antimicrobial therapy. The two arms of the study were similar in baseline clinical features, demographics, and Gram-negative pathogens' distribution. Acinetobacter baumannii (51.7%) was the major pathogen, followed by Klebsiella pneumonia (26.7%). Patients who received colistin-based antimicrobial regimen showed a non-significant difference compared to non-colistin antimicrobial (NCA) therapy (p > 0.05) in the main outcomes. Nephrotoxicity was significantly higher in the IV colistin group, compared to the control (34.1% and 15.3%, p = 0.018). There were substantial differences observed in the levels of serum creatinine and urea among the study arms (p = 0.029 and <0.001, respectively). Conclusions: The combination of colistin with other antimicrobial agents showed comparable results to that of NCA regimens in hospitalized COVID-19 patients with superinfections with multidrug-resistant bacterial isolates; however, there was a notably elevated incidence of nephrotoxicity with colistin antimicrobial therapy. Further randomized controlled trials are needed to assess the therapeutic benefits and tolerability of colistin antimicrobial therapy.