Assessment of Effective Antimicrobial Regimens and Mortality-Related Risk Factors for Bloodstream Infections Caused by Carbapenem-Resistant Acinetobacter baumannii

OBJECTIVE: This study aimed to determine the clinical features, risk factors, and effective antimicrobial therapy for Carbapenem-resistant Acinetobacter baumannii (CRAB) bloodstream infection (BSI). METHODS: This was a retrospective analysis of data from patients with CRAB bacteremia in a Chinese tertiary hospital between January 2012 and October 2021. Risk factors, predictors of 30-day mortality, and effective antimicrobial therapy for CRAB BSI were identified using logistic and cox regression analyses. RESULTS: Data from 276 patients with Acinetobacter baumannii (AB) BSI were included, of whom 157 (56.9%) had CRAB BSI. The risk factors that were significantly associated with CRAB BSI included previous intensive care unit (ICU) stay (P < 0.001), immunocompromised status (P < 0.001), cephalosporin use (P = 0.014), and fluoroquinolone use (P = 0.007). The 30-day mortality of the CRAB BSI group was 49.7% (78/157). ICU stay after BSI (P = 0.047), sequential organ failure assessment (SOFA) score ≥10 (P < 0.001), and multiple organ failure (MOF) (P = 0.037) were independent predictors of 30-day mortality. Among antibiotic strategies for the treatment of patients with CRAB BSI, we found that definitive regimens containing cefoperazone/sulbactam were superior to those without cefoperazone/sulbactam in reducing the 30-day mortality rate (25.4% vs 53.4%, P = 0.005). After propensity score matching, we observed a significant increase in the 30-day mortality (77.8%vs 33.3%, P = 0.036) in patients receiving tigecycline monotherapy compared to those receiving cefoperazone/sulbactam monotherapy. The mortality rate of patients receiving tigecycline with cefoperazone/sulbactam was also higher than that of patients receiving cefoperazone-sulbactam monotherapy; however, the difference was not significant (28.6%vs 19.0%, P = 0.375). CONCLUSION: The severity of patient conditions was significantly associated with mortality in patients with CRAB BSI. Those Patients treated with cefoperazone/sulbactam had better clinical prognoses, and tigecycline should be used with caution.