Robust marine bacterium-mediated synthesis of Cu-ZnO nanocomposites: a novel antibiofilm and antivirulent strategy to combat carbapenem-resistant Acinetobacter baumannii

Aims The rapid emergence of carbapenem-resistant Acinetobacter baumannii (CRAB) poses a significant threat to global health security, with high mortality rates. This study aims to develop biofabricated copper-doped zinc oxide nanocomposites (Cu-ZnO NCs) using cell-free extracts from the marine-derived Stenotrophomonas maltophilia and to evaluate their antibacterial, antibiofilm, and anti-efflux efficacy against CRAB.Materials and methods The biofabricated NCs were synthesized at three different concentrations (0.5, 1, and 3%) and characterized using several techniques to determine their physicochemical and morphological properties. Biological assays, including antibacterial, antibiofilm, and anti-efflux assessments, were investigated using in vitro methods.Results The biofabricated 1% Cu-ZnO NCs (80 μg/mL) effectively reduced the virulence phenotypes in CRAB, including biofilm formation, slime, and EPS-associated carbohydrate production in a concentration-dependent manner. Microscopic analysis revealed the disruption of biofilm architecture. In addition, NCs attenuated the CRAB virulence factors by reducing phospholipase production and efflux pump function.Conclusion These findings highlight the importance of biofabricated Cu-ZnO NCs as a promising antivirulent approach for combating carbapenem-resistant Acinetobacter baumannii.