Antimicrobial Resistance Mechanisms in Pseudomonas aeruginosa

Pseudomonas aeruginosa employs a multilayered defence against antimicrobial agents, combining intrinsic features, adaptive responses and acquired mutations. Intrinsic resistance arises from a low-permeability outer membrane and constitutive expression of efflux pumps that expel diverse compounds. Adaptive resistance involves biofilm formation, activation of stress-response pathways and phenotypic tolerance that transiently reduce susceptibility without genetic change. Acquired resistance is driven by mutations or horizontal gene transfer leading to overexpression of efflux systems (for example MexAB-OprM and MexXY), production of antibiotic-inactivating enzymes (β-lactamases, aminoglycoside-modifying enzymes), modification of drug targets (such as LPS alterations conferring colistin resistance) and loss or alteration of porins. Two-component regulatory systems and global transcriptional regulators (MexZ, MexT, AmpR, PmrAB, CzcRS) coordinate these pathways and may influence virulence and host adaptation. Small RNAs and quorum-sensing circuits further integrate environmental signals with resistance gene expression. In the context of chronic infections such as cystic fibrosis lung disease or intensive-care settings, selective pressures from antibiotic therapy and host defences accelerate the evolution of multi-drug resistance, posing a major global health challenge and underscoring the need for novel therapeutic strategies.

Research from Nature Portfolio

Recent studies have elucidated the interplay between efflux regulation and tissue colonisation. Mutations in the mexZ regulator not only upregulate the MexXY pump to confer low-level aminoglycoside tolerance, but also disrupt balance with MexAB, leading to overproduction of a quorum-sensing lectin that promotes epithelial invasion and protects bacterial aggregates from multiple antibiotics within a human airway model. Separately, the genetic pathways to high-level resistance against antimicrobial peptides such as colistin have been mapped by experimental evolution and whole-genome sequencing. These experiments reveal that resistance requires concerted mutations across multiple loci, with key transcriptional regulators acting as epistatic nodes that potentiate subsequent changes. This work highlights the predictability of evolutionary routes to peptide resistance and informs strategies to forestall or reverse the emergence of pan-resistant strains.

Antimicrobial Resistance Mechanisms in Pseudomonas aeruginosa publication trend

The graph below shows the total number of articles in antimicrobial resistance mechanisms in pseudomonas aeruginosa across all publications each year (not limited to Nature Index journals).

Technical terms

Efflux pump: Protein complex that expels antibiotics and other toxins from the bacterial cell.

Two-component system: Sensor-regulator pair that detects environmental stimuli and modulates gene expression.

Biofilm: Surface-attached microbial community embedded in a protective extracellular matrix.

Quorum sensing: Cell-to-cell signalling mechanism that coordinates group behaviours including virulence and resistance.

Epistasis: Interaction between mutations whereby one change influences the effect of another on resistance.

References

1. The Building Blocks of Antimicrobial Resistance in Pseudomonas aeruginosa: Implications for Current Resistance-Breaking Therapies. Frontiers in Cellular and Infection Microbiology (2021).
2. Mutations in the efflux pump regulator MexZ shift tissue colonization by Pseudomonas aeruginosa to a state of antibiotic tolerance. Nature Communications (2024).
3. The evolution of antimicrobial peptide resistance in Pseudomonas aeruginosa is shaped by strong epistatic interactions. Nature Communications (2016).
4. Multidrug resistance in Pseudomonas aeruginosa: genetic control mechanisms and therapeutic advances. Molecular Biomedicine (2024).
5. Uncovering a new family of conserved virulence factors that promote the production of host‐damaging outer membrane vesicles in Gram‐negative bacteria. Journal of Extracellular Vesicles (2025).
6. Mutations in mexT bypass the stringent response dependency of virulence in Pseudomonas aeruginosa. Cell Reports (2024).