Clinical and molecular predictors of mortality in patients with carbapenem-resistant Acinetobacter baumannii bacteremia: A retrospective cohort study

/Purpose: To investigate the virulence profiles and identify clinical and microbiological predictors of mortality in patients with carbapenem-resistant Acinetobacter baumannii (CRAB) bacteremia. This retrospective cohort study enrolled adult patients with CRAB. Multivariate logistic regression was used to identify the predictors of 30-day mortality. All isolates were subjected to real-time polymerase chain reaction for virulence factors and genotyped using multilocus sequence typing. Among the 153 patients with CRAB bacteremia, 66% received appropriate definitive antibiotic therapy. The in-hospital and 30-day mortality rates were 58.3 and 23.5%, respectively. Ultimately, we enrolled 125 patients with CRAB bacteremia in the analysis, excluding early mortality cases. All CRAB isolates carried blaOXA-23 and blaOXA-51. The clinical strains belonged to 10 sequence types (STs), and the major genotypes were ST191, ST195, ST451, and ST784. The distribution of virulence factors included surface adhesion (Ata, 84.8%; ChoP, 7.2%), biofilm formation (OmpA, 76.8%), killing of host cells (AbeD, 99.2%), toxins (LipA, 99.2%), and conjugation (BfmR, 90.4%). In multivariate logistic regression analysis, hemodialysis due to acute kidney injury and moderate to severe thrombocytopenia were significant risk factors associated with 30-day mortality. However, microbiological factors were not significant predictors. Clinical factors such as hemodialysis due to acute renal injury and moderate to severe thrombocytopenia have a greater influence on mortality in CRAB bacteremia compared with microbiological factors.