Efficacy and Safety of Three Colistin Regimens in the Treatment of Nosocomial Pneumonia Caused by Carbapenem-Resistant Organisms: A Single Centre, Open Label, Prospective Cohort Study

Background The optimal route of colistin administration for treating carbapenem-resistant organisms (CRO) nosocomial pneumonia remains unclear. The objective of this study was to assess the efficacy and safety of three distinct regimens that are based on colistin. Methods 98 patients with nosocomial pneumonia caused by CRO who received colistin treatment in the intensive care unit were included in this prospective cohort study. Based on the route of administration, patients were categorized into three groups: inhalation (IH), combined intravenous plus inhalation (IV + IH), and intravenous (IV). Clinical efficacy was the primary outcome at the end of the treatment. Secondary outcomes involved 28-day all-cause mortality, microbiological response, nephrotoxicity, and duration of hospital stay. Results The clinical efficacy rates were 70.0% for the IH group, 64.7% for the IV + IH group, and 64.3% for the IV group, with no significant differences observed ( P  = 0.834). Patients in the IH group achieved significantly better microbiological outcomes compared to those in the IV group ( P  = 0.009). However, no substantial differences were observed among the groups regarding 28-day all-cause mortality, duration of hospital stay, or incidence of acute kidney injury. Moreover, higher APACHE II scores, the existence of sepsis, and the occurrence of acute kidney injury were identified as factors related to clinical treatment failure. Conclusion In the treatment of nosocomial pneumonia caused by CRO, inhaled administration demonstrated non-inferior clinical efficacy compared to systemic administration and was associated with a higher incidence of microbiological eradication.