The membrane composition defines the spatial organization and function of a major Acinetobacter baumannii drug efflux system

Acinetobacter baumannii is one of the world's most problematic nosocomial pathogens. The combination of its intrinsic resistance and ability to acquire resistance markers allow this organism to adjust to antibiotic treatment. Despite being the primary barrier against antibiotic stress, our understanding of the A. baumannii membrane composition and its impact on resistance remains limited. In this study, we explored how the incorporation of host-derived polyunsaturated fatty acids (PUFAs) is associated with increased antibiotic susceptibility. Functional analyses of primary A. baumannii efflux systems indicated that AdeB-mediated antibiotic resistance was impacted by PUFA treatment. Molecular dynamics simulations of AdeB identified a specific morphological disruption of AdeB when positioned in the PUFA-enriched membrane. Collectively, we have shown that PUFAs can impact antibiotic efficacy via a vital relationship with antibiotic efflux pumps. Furthermore, this work has revealed that A. baumannii's unconditional desire for fatty acids may present a possible weakness in its multidrug resistance capacity.