Azelaic Acid as a Novel Antivirulence Agent Against Pseudomonas aeruginosa: In silico, In vitro and In vivo Efficacy and Biocompatibility

Abstract

Pseudomonas aeruginosa is an opportunistic pathogen whose virulence is largely regulated by quorum sensing (QS), making this system an attractive target for anti-virulence therapies. Azelaic acid (AzA), a naturally occurring dicarboxylic acid widely used in dermatology, has not previously been investigated as a QS inhibitor. This study evaluated the antibacterial and anti-virulence activities of AzA against reference strains and multidrug-resistant clinical isolates of P. aeruginosa, together with its preliminary safety profile and potential molecular interactions with key QS proteins. Minimum inhibitory concentrations (MICs) ranged from 250 to 1000 {micro}g/mL. At sub-inhibitory concentrations, AzA significantly reduced the production of pyocyanin, elastase, protease and alginate in a dose-dependent manner without affecting bacterial viability. Molecular docking predicted favorable interactions of AzA with LasI, LasR, PqsD and PqsR, supporting a potential modulation of QS-associated pathways. Chemoinformatic analyses predicted favorable drug-likeness and safety characteristics, while PBMC viability remained above 90% and hemolysis below 4% within the anti-virulence concentration range. In the Tenebrio molitor infection model, AzA significantly increased larval survival and reduced in vivo pyocyanin production in both the reference strain Pa14 and a multidrug-resistant clinical isolate. Collectively, these findings provide the first evidence that AzA attenuates QS-regulated virulence in P. aeruginosa through complementary in vitro, in silico and in vivo approaches while exhibiting a favorable preliminary safety profile. These results support the repositioning of AzA as a promising anti-virulence candidate for the development of adjunctive therapeutic strategies against multidrug-resistant P. aeruginosa infections.