Epidemiological Analysis of Health Care–associated Infections Caused by Acinetobacter Baumannii in a Tertiary Trauma Hospital, 2021–2024

Acinetobacter baumannii is an opportunistic bacterium with notable ability to acquire resistance to multiple antibiotic classes and is frequently associated with health care–associated infections (HAIs). Despite its severity, there is no consensus on the ideal therapeutic regimen, and choice often considers individual patient and institutional characteristics. This study aims to conduct an epidemiological analysis of A. baumannii HAIs in a tertiary trauma hospital. A retrospective study of HAIs caused by A. baumannii between 2021 and 2024. Osteomyelitis cases were excluded. A total of 159 HAIs were reviewed. The sample was predominantly male (79.9%), with a predominance of ages 18–39 years (37.1%). The main reasons for hospitalization were trauma (38.4%) and neurological conditions (19.5%), including traumatic brain injury. Nearly all patients used some invasive device prior to infection (98.7%), with mechanical ventilation the most frequent (91.2%). Antibiotics were used before infection onset in 74.8% of patients. The main infection site was the lung (76.7%), followed by bloodstream (6.3%). Increased resistance to some antimicrobials was observed, notably: amikacin from 51.3% (2021) to 88.2% (2024); meropenem from 76.3% to 94.1%; and polymyxin B from 1.3% to 29.4%. Among patients who received antibiogram-guided therapy, monotherapy and dual therapy were used in 52.8% and 43% of cases, respectively. Polymyxin B (56.9%), meropenem (37.5%), and amikacin (25%) were the most used antimicrobials, and most cases had treatment duration between 6 and 10 days (49.3%). Although only 9.5% of patients received treatment considered inadequate, overall mortality was high (42.1%), reaching 58.8% in 2024. The population studied—young, otherwise healthy men hospitalized for trauma—differs from populations in other studies. Even so, the association of A. baumannii infection with neurological injuries, prior antimicrobial use, and invasive devices aligns with current literature. The high mortality rate reinforces the bacterium’s role as a marker of severity in critically ill patients, and understanding epidemiological factors is essential to improve management of these infections.