2025, Vol. 5, Issue 2, Part B

Background: Pseudomonas aeruginosa is one such clinically relevant Gram-negative pathogen and it is involved with chronic biofilm-mediated infections and intrinsic antibiotic resistance. Its virulence depends mostly on the quorum sensing (QS) systems which regulate the production of such virulence factors as immune evasion, biofilm development and virulence factors. There is a prospect of decreasing the virulence of these bacteria by going after these couple of communication mechanisms without creating a selective pressure to develop resistance.

Objective: In this research, P. aeruginosa was selected as the main target of the dual-function nanotherapeutic platform that would interfere with the functioning of QS-regulated bacteria phenotype as well as boost the host immune defense.

Methods: The QS inhibitor furanone C-30, an immune-stimulatory ligand CpG-ODN or MPLA were surface-functionalized into a nanostructure (NP-DUAL) by encapsulated cores of PLGA and gold. All microbiological analysis was done using P. aeruginosa PAO1. AI-2 reporter based on assays and pyocyanin quantitation were used to measure QS activity. Biomass of a biofilm was calculated through crystal violet staining. In vitro immunological functions were determined by the use of RAW 264.7 macrophages and human dendritic cells. In vivo efficacy was studied in the mouse subcutaneous infection model by challenge of P. aeruginosa.

Results: Attachment interference on QS plays a very important role since NP-DUAL severely disrupted the QS signaling in P. aeruginosa, deactivating AI-2 by 72 %, pyocyanin 65 % and biofilm biomass by 66 %. There was also a broader activated immune response measured by higher levels of cytokine (TNF-alpha, IL 6, IL 12) secretion and acceleration of phagocytic bacterial killing of cells by the nanostructures. Treatment in vivo resulted in significant declines in the bacterial burden and tissue regeneration in infected mice.

Conclusion: The study proves that P. aeruginosa is a potential target of dual-action nano therapy. Our NP-DUAL system interferes with QS-driven virulence and provides an antimicrobials- neutral resistance, likely to chelate and reduce antimicrobials on the one hand, and it boosts and promotes host immunity on the other hand. The approach of focusing on bacterial interruption is by targeting pathogen coordination, and persistence as an important source of future antimicrobial innovation.