Clinical outcomes and mortality in carbapenem-resistant versus susceptible Klebsiella pneumoniae bloodstream infections in intensive care units

BACKGROUND: Carbapenem-resistant Klebsiella pneumoniae (CRKP) has emerged as a major global health threat due to increasing prevalence, limited treatment options, and high associated mortality rates. Bloodstream infections (BSIs) caused by CRKP, particularly in intensive care units (ICUs), pose significant clinical challenges. This study aimed to evaluate the risk factors and mortality outcomes of CRKP compared to carbapenem-susceptible K. pneumoniae (CSKP) BSIs. METHODS: This retrospective study included 189 adult ICU patients with K. pneumoniae BSIs from 2017 to 2025. Patients were classified into CRKP and CSKP groups based on antimicrobial susceptibility. Demographic, clinical, and microbiological data were analyzed. Independent risk factors for CRKP BSIs were identified using multivariable logistic regression, and predictors of mortality were evaluated using Cox proportional hazards regression. Survival outcomes were assessed using Kaplan-Meier analysis. RESULTS: Of the 189 patients, 113 (59.8%) had CRKP-BSI and 76 (40.2%) had CSKP-BSI. In multivariable logistic regression analysis, immunosuppressive therapy (odds ratio [OR]: 4.19, 95% confidence interval [CI]: 1.61-12.30, p = 0.005), mechanical ventilation (OR: 3.81, 95% CI: 1.69-9.03, p = 0.002), ICU hospitalization within the previous three months (OR: 2.60, 95% CI: 1.27-5.48, p = 0.01) were identified as independent risk factors for CRKP infections. No significant differences were observed between the two groups regarding age, gender, severity scores (p > 0.05). In the multivariable Cox regression analysis, age ≥ 65 years (Hazard Ratio [HR]: 1.54, 95% CI: 1.02-2.32, p = 0.041) and mechanical ventilation (HR: 2.26, 95% CI: 1.38-3.70, p = 0.001) were identified as independent risk factors for mortality. Kaplan-Meier analysis showed no significant difference in 28-day survival between patients with CRKP and CSKP BSIs in ICUs (log-rank p = 0.45). CONCLUSIONS: Recent ICU hospitalization, immunosuppression, and mechanical ventilation appear to be important factors associated with CRKP-BSIs, whereas age ≥ 65 years and mechanical ventilation were independently associated with increased mortality among patients with K. pneumoniae BSIs in ICU patients. CLINICAL TRIAL: Not applicable.