Abstract

Introduction

Carbapenem-resistant Gram-negative bacteria (CR-GNB) represent a major global health challenge, associated with limited therapeutic alternatives and elevated mortality rates. This study aimed to evaluate factors linked to mortality in bloodstream infections (BSI) caused by CR-GNB and to compare the effectiveness of various treatment modalities.

Materials and Methods

We conducted a single-center, retrospective cohort study of all consecutive patients with hospital-acquired CR-GNB BSI treated in the intensive care unit (ICU) of a 1010-bed tertiary university hospital between 2019 and 2022. Demographic characteristics, severity scores, invasive procedures, antibiotic regimens, and 28-day mortality outcomes were collected.

Results

A total of 156 patients met the inclusion criteria. The mean age was 68.6±15.8 years, and 91 (58.3%) were male. The overall 28-day mortality rate was 52.5%. Mortality was significantly higher among patients who underwent mechanical ventilation (p<0.001) or central venous catheterization (p=0.005) and among those with solid organ malignancy (p<0.001), hematologic malignancy (p<0.001), or immunosuppressive therapy (p=0.024). Independent predictors of mortality included Charlson Comorbidity Index [odds ratio (OR), 1.55; 95% confidence interval (CI), 1.22-1.97; p<0.001], septic shock (OR, 6; 95% CI, 1.74-21.18; p=0.05), total parenteral nutrition (TPN) (OR, 202.7; 95% CI, 13.5-3036.9; p<0.001), length of ICU stay prior to bacteremia diagnosis (OR, 0.95; 95% CI, 0.91-0.99; p=0.04), and receipt of effective treatment based on antibiogram results (OR, 0.06; 95% CI, 0.01-0.34; p=0.002). Mortality did not differ remarkably between patients receiving combination therapy and those receiving monotherapy, nor between those who received appropriate empiric therapy and those who did not.

Conclusion

Where feasible, invasive procedures such as central venous catheterization and mechanical ventilation should be minimized. TPN should be reserved for cases where alternative nutritional support is not possible. Mortality was reduced by the administration of effective therapy guided by antibiogram results. Given the scarcity of effective agents, the development of new antibiotics remains an urgent priority.