Membrane Protein Mechanisms in Antibiotic Resistance of Acinetobacter baumannii

Acinetobacter baumannii is a Gram‐negative pathogen notorious for hospital‐acquired infections and formidable multidrug resistance. Central to this resilience are membrane‐associated proteins that control antibiotic influx and efflux, localise inactivation enzymes and modulate virulence. Porins such as CarO and OprD regulate entry of carbapenems and other β-lactams, with mutations or downregulation diminishing drug uptake. Outer membrane protein A (OmpA) contributes both to membrane integrity and biofilm formation, indirectly affecting local antibiotic concentrations. Efflux systems spanning the inner and outer membranes further expel diverse antibiotics, often working in concert with membrane permeability changes. Outer membrane vesicles (OMVs) pack enzymes like metallo-β-lactamases, disseminating resistance factors to neighbouring cells. Protein–protein interaction networks anchor carbapenemases at porin sites, ensuring efficient hydrolysis of incoming drugs. These mechanisms intertwine with regulatory pathways and horizontal gene transfer, driving rapid adaptation. Understanding the structural and functional diversity of these membrane proteins offers routes to novel therapeutics, from inhibitors targeting porin–enzyme complexes to vaccines directed against surface antigens.

Research from Nature Portfolio

In-depth network analysis of a multidrug‐resistant clinical strain revealed that outer membrane porins and associated carbapenemases form stable interaction hubs. These interactions localise antibiotic‐inactivation enzymes at porin channels, ensuring rapid hydrolysis of incoming carbapenems and highlighting porin–enzyme complexes as potential drug targets. A separate study established validated reference genes for precise quantification of membrane protein gene expression by reverse transcription quantitative PCR. Using these controls, researchers accurately measured changes in OmpA levels in polymyxin‐resistant and sensitive strains, laying groundwork for detailed expression profiling of membrane proteins under antibiotic stress.

Membrane Protein Mechanisms in Antibiotic Resistance of Acinetobacter baumannii publication trend

The graph below shows the total number of articles in membrane protein mechanisms in antibiotic resistance of acinetobacter baumannii across all publications each year (not limited to Nature Index journals).

Technical terms

Outer membrane protein (OMP): A protein embedded in the outer membrane of Gram-negative bacteria involved in transport, structural stability and interactions with the environment.

Porin: A subclass of OMP forming water-filled channels that permit passive diffusion of small molecules, including certain antibiotics.

Outer membrane vesicle (OMV): Spherical, bilayered fragments shed from the bacterial outer membrane carrying lipids, proteins and resistance enzymes.

Carbapenemase: An enzyme capable of hydrolysing carbapenem antibiotics, rendering them ineffective.

Persister cell: A transient, dormant bacterial subpopulation tolerant to high antibiotic concentrations without genetic resistance.

Efflux pump: A membrane-spanning protein complex that actively transports antibiotics and other toxic compounds out of the cell.

References

1. In vivo protein interaction network analysis reveals porin-localized antibiotic inactivation in Acinetobacter baumannii strain AB5075. Nature Communications (2016).
2. Selection and validation of reference genes suitable for gene expression analysis by Reverse Transcription Quantitative real-time PCR in Acinetobacter baumannii. Scientific Reports (2024).
3. Increased ompW and ompA expression and higher virulence of Acinetobacter baumannii persister cells. BMC Microbiology (2023).
4. Outer membrane vesicles of carbapenem-resistant clinical Acinetobacter baumannii isolates protect both the vesicle-producing bacteria and non-resistant bacteria against carbapenems. Microbiological Research (2025).
5. The Outer Membrane Proteins OmpA, CarO, and OprD of Acinetobacter baumannii Confer a Two-Pronged Defense in Facilitating Its Success as a Potent Human Pathogen. Frontiers in Microbiology (2020).