Multidrug-resistant Acinetobacter baumannii infections have become a threat for public health worldwide. The aim of the present study was to follow-up resistance patterns of Acinetobacter spp. bloodstream isolates in a Tertiary University Hospital over the last nine years, from 2014 to 2022. Susceptibility patterns were followed for the following antimicrobial agents: amikacin, gentamicin, tobramycin, ciprofloxacin, levofloxacin, imipenem, meropenem, tigecycline, trimethoprim/sulfamethoxazole, and colistin. Minimal inhibitory concentration (MIC) values to ampicillin/sulbactam, cefepime, ceftazidime, minocycline, piperacillin/tazobactam were evaluated from 2020 to 2023. During the study period, 853 Acinetobacter spp. bloodstream infections (BSIs) were recorded, accounting for 5.36% of all BSIs. A. baumannii was isolated in 795 cases (93.2%), during the study period. Most BSIs were recorded in adult intensive care units (ICU) (46.2%) and medical wards (42%). Among A. baumannii isolates, 4.5% were multidrug-resistant, 84.7% were extensively drug-resistant, and 8.5% were pandrug-resistant. Resistance to carbapenems was over 95%. Resistance to tigecycline increased significantly during the last years of the study (2020-2022); A. baumannii isolates with MIC ≤ 2 μg/mL accounted for 28.5% of all isolates. Resistance to colistin exhibited an increasing pattern up to 42.2% in 2022. Increasing resistance rates and the evolution of pandrug-resistant isolates call for the urgent application of preventive and response actions.
Keywords: A. baumannii; Acinetobacter; ICU infections; bloodstream infections; carbapenems; colistin; extensively drug-resistant; multidrug-resistant; pandrug-resistant; tigecycline.