Prevalence and Antimicrobial Resistance of Acinetobacter baumannii Isolates at Lebanese Hospital Geitaoui-University Medical Center: A Five-Year Study (2017-2021)

Acinetobacter baumannii is a critical opportunistic pathogen known for causing serious healthcare-associated infections and exhibiting alarming levels of antimicrobial resistance. This study aims to determine the prevalence and antimicrobial resistance patterns of A. baumannii isolates at Lebanese Hospital Geitaoui-University Medical Center over a five-year period. Clinical isolates of A. baumannii collected between 2017 and 2021 were analyzed. Patient gender, specimen type, year of isolation, and susceptibility profiles were obtained from electronic medical records. Bacterial identification was performed using API 20NE and VITEK system. Antimicrobial susceptibility testing against 14 antibiotics was performed using the Kirby-Bauer disk diffusion method and complemented by the VITEK2 automated system, with interpretations based on CLSI guidelines. A total of 492 A. baumannii isolates were identified from 9,626 clinical samples (5.11%). Prevalence increased from 2.92% in 2017 to 9.48% in 2021. The majority of isolates were recovered from sputum samples, followed by blood, swabs, and urine specimens. Infections were more common in males (67%) than females (33%). The isolates exhibited high levels of multidrug resistance. Only tigecycline and colistin retained 100% effectiveness throughout the study period. The increasing prevalence and extensive antimicrobial resistance of A. baumannii underscore the urgent need for national surveillance programs, stricter infection control protocols, and updated antimicrobial guidelines.