Mortality-related Risk Factors And Assessment Of Effective Antimicrobial Regimens For Bloodstream Infections Caused By Carbapenem-Resistant Acinetobacter Baumannii

Objective:This study aimed to investigate the drug resistance characteristics of Acinetobacter baumannii(AB)causing bloodstream infection,determine the clinical features,risk factors,and effective antimicrobial therapy for Carbapenem-resistant Acinetobacter baumannii bloodstream infection(CRAB-BSI).Methods:This was a retrospective analysis of data from patients with AB bacteremia in the Second Affiliated Hospital of Nanchang University between January 2012 and October 2021.The drug resistance characteristics and clinical features of the CRAB and non-CRAB groups were compared using the chi-square test.Risk factors,predictors of 30-day mortality,and effective antimicrobial therapy for CRAB-BSI were identified using logistic analyses.Results:Data from 276 patients with Acinetobacter baumannii bloodstream infection(AB-BSI)were included,of whom 157(56.9%)had CRAB-BSI.CRAB isolates showed significantly higher resistance rates to b-lactam/enzyme inhibitors,cephalosporins,quinolones,aminoglycosides,tigecycline and cotrimoxazole than non-CRAB strains.Patients with CRAB-BSI had more distinct hospital exposures and more serious conditions than those with non-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 was49.7%(78/157).ICU stay after BSI(P = 0.003),sequential organ failure assessment(SOFA)score ≥10(P = 0.001),and multiple organ failure(MOF)(P = 0.003)were independent predictors of 30-day mortality.Among antibiotic strategies for the treatment of patients with CRAB BSI,we found that definitive regimens containing efoperazone-sulbactam were superior to those without cefoperazone-sulbactam in reducing the 30-day mortality rate(25.4% vs.51.2%,P = 0.005).In subsequent analysis,we observed a significant increase in the 30-day mortality(66.7% vs.21.6%,P = 0.033)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(31.8% vs.21.6%,P = 0.221).Conclusion:More distinct hospital exposure before bacteremias increases the risk of CRAB-BSI.Patients with CRAB-BSI treated with cefoperazone-sulbactam had better clinical prognoses,and tigecycline should be used with caution.