Acinetobacter baumannii in the Age of Antimicrobial Resistance: Clinical Impact, Therapeutic Approaches, and Vaccine Development.

Acinetobacter baumannii is a globally prevalent Gram-negative pathogen responsible for a substantial proportion of healthcare-associated infections, particularly in intensive care units. Its ability to persist in hospital environments, form biofilms on medical devices, and evade host immune responses has contributed to the rapid emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. This narrative review was conducted through a comprehensive literature search of PubMed, Scopus, Web of Science, and Google Scholar, focusing on studies published primarily over the past two decades. The review summarizes global epidemiology, vulnerable populations, mechanisms of antimicrobial resistance, clinical and economic impacts, and current and emerging therapeutic strategies. The advances in alternative treatments, including antimicrobial peptides, bacteriophage therapy, and vaccine development, are also discussed. In addition to summarizing existing knowledge, this review critically examines the key limitations underlying current therapeutic and vaccine strategies, including rapid resistance evolution, immune evasion, and antigenic variability. It further identifies major translational gaps and proposes future directions integrating systems biology and multitarget approaches. Although preclinical studies demonstrate the promising efficacy of several vaccine candidates, clinical trials in humans remain necessary to confirm their safety and effectiveness.