From computational screening to in vitro validation: exploring antimicrobial peptides against Pseudomonas aeruginosa.

Advanced therapeutics such as antimicrobial peptides (AMPs) represent promising alternatives for combating antimicrobial resistance due to their diverse mechanisms of action, including membrane disruption and interference with bacterial resistance systems. Pseudomonas aeruginosa is recognized as a priority pathogen because of its intrinsic and acquired resistance to multiple antibiotics, largely mediated by the overexpression of efflux pump systems such as MexAB-OprM. In this study, an extensive in-silico screening approach was employed to identify AMPs capable of interacting with the MexB efflux pump protein. Molecular docking and molecular dynamics simulations identified Omiganan, SAAP-148, and their engineered variants as promising candidates with strong binding affinity toward MexB. Selected peptides were synthesized and evaluated in vitro against clinical and reference strains of P. aeruginosa. The peptides exhibited minimum inhibitory concentrations ranging from 8 to 64 μg/mL. Flow cytometric analysis using propidium iodide uptake and scanning electron microscopy confirmed membrane disruption in peptide-treated cells. Cytotoxicity assays demonstrated comparatively low toxicity for Omiganan and SAAP-148_SM1 in HEK293 and HepG2 cell lines. Collectively, these findings highlight the potential of rationally designed antimicrobial peptides as modulators of efflux-mediated resistance. The identified peptides provide a foundation for further optimization and in vivo evaluation as potential therapeutic agents or antibiotic adjuvants against multidrug-resistant P. aeruginosa infections.