Old drugs, new lifelines: An update on drug repurposing against multidrug-resistant Acinetobacter baumannii

Multidrug-resistant (MDR) Acinetobacter baumannii is a WHO priority pathogen that endures in hospitals and complicates care in intensive care units. Drug repositioning offers a faster path to therapies by reusing approved agents with known safety. This review compiles in vitro and in vivo evidences for repurposed candidates against MDR A. baumannii. Repurposing of anticancer drugs displayed bacterial load reduction and enhancement of polymyxin B through membrane permeabilization. Additionally, antiparasitics increased colistin efficacy by altering surface charge. Furthermore, central nervous system (CNS) agents contributed synergy with traditional antibiotics. Anti-inflammatory and other agents also showed promise: diclofenac enhanced colistin killing, desloratadine blocked growth and synergized with meropenem, and auranofin paired with pentamidine achieved bactericidal effects. Translating these signals will require attention to dosing, delivery, and safety, and rigorous clinical trials. In total, repurposing, particularly in rational combinations, could supply near-term options for severe MDR A. baumannii infections.