Comparison of pneumonia and nonpneumonia-related Acinetobacter baumannii complex bacteremia: A single-center retrospective study

Abstract

Acinetobacter baumannii complex (ABC) is a group of increasingly prevalent opportunistic pathogens that cause a variety of life-threatening nosocomial infections, especially in the intensive care unit (ICU). This study assessed the differences between pneumonia- and non-pneumonia-related ABC bacteremia and possible independent risk factors for 30-day mortality. The clinical data of ICU patients diagnosed with ABC bacteremia at a tertiary care hospital from January 2009 to December 2020 were collected, and sorted into groups of ABC bacteremia with and without pneumonia. Significant changes in the incidence of ABC bacteremia and antibiotic resistance were observed over the 12-year study. Compared with nonpneumonia-related ABC bacteremia, pneumonia-related ABC bacteremia was associated with a higher rate of hypertension, less prior tigecycline use, more carbapenem-resistant (CR) strains, and a higher 30-day mortality rate. In multivariate analysis, immunosuppression, higher APACHE II score, and SOFA score were independent risk factors for 30-day mortality. Moreover, the risk of death was 1.919 times higher in the pneumonia-related group. Although pneumonia-related ABC bacteremia had worse outcomes, it was not an independent risk factor for death statistically. Immunosuppression and disease severity levels increased the risks of death in ICU patients with ABC bacteremia.