P05. Predictive factors of early and late mortality and evaluation of therapeutic efficacy in patients with bacteremia associated with MDR Acinetobacter baumannii: the Itaca (Italian advances on carbapenem-resistant Acinetobacter) study

Carbapenem-resistant Acinetobacter baumannii (CRAB) infection, especially bacteremia, represents a major challenge for clinicians due to high morbidity and mortality rates.

This is an observational, prospective, multicenter study conducted in 52 Italian centers for 18 months in hospitalized patients who developed clinically significant infection and concomitant bacteremia with CRAB. Patients aged >18 years with microbiological isolates from CRAB blood cultures, who developed a clinical syndrome in the absence of other isolates, and who received targeted antibiotic therapy for at least 24 hours were enrolled. The primary objective of the study was the analysis of factors that could predict mortality at 14 and 30 days after the development of infection.

During study period, 398 patients were enrolled. Out of these, 140 (35.2%) were male, the mean age was 67 years, and the mean Charlson Comorbidity Index was 5 points. The source of bacteremia was primary in 34.8% of patients, CVC-related in 19.1%, secondary to hospital-acquired pneumonia in 23.6% and ventilator-associated pneumonia in 22.5%. Other sources were intra-abdominal, urinary or skin and soft tissue infection. Overall, 89/398 (22.3%) died at 14 days and 107/398 (26.8%) at 30 days. At univariate analysis, follow-up blood cultures were more frequently negative in survivors (75.3%) compared to non survivors (48%) at 14 days (P = 0.008); cefiderocol containing-regimen was associated with survival at 14 days (P < 0.001). At logistic regression analysis, therapeutic failure (OR 4.03, CI 95% 2.16–7.5, P < 0.001, primary bacteremia (OR 2.1, CI 95% 1.1–3.7, P = 0.01), and previous colonization by Acinetobacter baumannii (OR 3.5, CI 95% 1.7–7.3, P < 0.001) were independently associated with 30-day mortality, while respiratory improvement after 72 hours from targeted therapy (OR 0.25, CI 95% 0.13–0.49, P < 0.001) with 30-day survival.

data highlighted factors associated with death or survival in bacteremic CRAB infections. These observations represent an important advance in the management of this difficult-to-treat infections.