Impact of COVID-19 on epidemiology and mortality risk factors in patients with carbapenem-resistant Acinetobacter baumannii bloodstream infections in a tertiary care hospital in Thailand

Objective: To investigate the epidemiology of Acinetobacter baumannii isolates and bloodstream infections (BSIs) during the COVID-19 pandemic. Methods: A. baumannii isolated from clinical specimens were identified between 2019 and 2023. The quarterly incidence of carbapenem-resistant A. baumannii (CRAB) was described. Hospital-wide carbapenem consumption was quantified as defined daily doses (DDD). Risk factors for CRAB acquisition and 30-day all-cause mortality in CRAB BSIs were determined. Results: A total of 400 new CRAB cases were identified. The incidence of total CRAB clinical isolates fluctuated (P = 0.68), while the incidence of CRAB BSIs increased (P = 0.04). No correlation was found between CRAB incidence and hospital-wide carbapenem consumption (P = 0.93). There were 75 CRAB BSI cases and 47 non-carbapenem-resistant A. baumannii (NCRAB) BSI cases. Prior antibiotic exposure (aOR 8.67; P < 0.001) and presence of multidrug-resistant organisms (MDROs) within 90 days (aOR 4.63; P = 0.02) were significantly associated with CRAB BSI acquisition. CRAB BSIs had higher 30-day mortality (66.67%) than NCRAB BSIs (25.53%) (aHR 0.83, 95% CI 0.26–2.59; P = 0.74). Pitt bacteremia score (aHR 1.20; P = 0.01) and recent COVID-19 infection (aHR 2.86; P = 0.03) were independent predictors of mortality in CRAB BSIs. Conclusions: The incidence of total CRAB clinical isolates fluctuated, while the incidence of CRAB BSIs significantly increased. Previous antimicrobial exposure and presence of MDROs within 90 days were risk factors for CRAB. Pitt bacteremia score and recent COVID-19 infection were linked to higher CRAB BSI mortality.