Clinical characteristics, treatment outcomes, and risk factors for mortality in post-neurosurgical central nervous system infections caused by Acinetobacter baumannii: a retrospective cohort study.

BACKGROUND

Post-neurosurgical central nervous system infections (PCNSIs) caused by Acinetobacter baumannii pose a significant therapeutic challenge; however, comprehensive studies focusing on this specific scenario are limited. This study aims to analyze the clinical characteristics, treatment outcomes, and prognostic factors of patients with PCNSIs caused by Acinetobacter baumannii.

METHODS

A retrospective cohort study was conducted at Guangdong Sanjiu Brain Hospital from January 2020 to June 2025. Patients diagnosed with Acinetobacter baumannii PCNSIs were included and stratified into carbapenem-resistant Acinetobacter baumannii (CRAB) and carbapenem-susceptible Acinetobacter baumannii (CSAB) groups. Clinical data, treatment regimens, and outcomes were analyzed. The primary outcome was 28-day all-cause mortality. Variables selected by LASSO regression were entered into univariate and multivariate Firth's logistic regression models to identify risk factors associated with mortality.

RESULTS

A total of 47 cases were included in the study, with 37 (78.7%) attributed to CRAB and 10 (21.3%) to CSAB. The 28-day mortality rate for CRAB infections was 37.8% (14/37), while no deaths occurred in the CSAB group (P = 0.022). In the CRAB group, Kaplan-Meier analysis indicated that non-polymyxin B-based regimens were associated with significantly higher mortality (70.5%) compared to polymyxin B-based regimens (10.0%; P < 0.001). Univariate analysis revealed that drainage performed following infection (OR = 0.087, 95% CI:0.008-0.502, P = 0.005), polymyxin B-based regimen (OR = 0.059, 95% CI:0.009-0.274, P < 0.001) and mechanical ventilation (OR = 4.399, 95% CI:1.127-19.002, P = 0.033) differed significantly between the groups. Multivariate analysis identified polymyxin B-based regimen as an independent factor associated with lower 28-day mortality (OR = 0.075, 95% CI: 0.008-0.402, P = 0.002).

CONCLUSION

CRAB-related PCNSIs are associated with significantly higher mortality compared to CSAB infections. Polymyxin B-based therapy may be associated with improved survival outcomes, while mechanical ventilation may be associated with an increased risk of mortality, warranting heightened clinical vigilance. Although post-infection drainage showed a protective effect in univariate analysis, it did not retain statistical significance as an independent predictor in the multivariable model, suggesting only a potential benefit that requires further validation.

TRIAL REGISTRATION: Not applicable.