High‐Yield Outer Membrane Vesicles Derived From Probiotics as a Nanoplatform for Precise Treatment and Prophylaxis of <i>Pseudomonas aeruginosa</i> Infection

Bacterial outer membrane vesicles (OMVs) are emerging as promising platforms for drug delivery and immunotherapy. However, bacteria only secrete a small amount of OMVs during the growth process, which seriously restricts their large-scale application. Here, a series of high-yield OMVs mutants is developed based on probiotic Escherichia coli Nissle 1917 (EcN). The mutant strain (EcNΔtolRΔmlaE) with the highest OMVs yield reported so far is identified and characterized, and its OMVs yield is 180.8 times that of the wild-type strain. More importantly, a high-yield OMVs mutant (EcNΔtolAΔnlpI) that derived OMVs can significantly improve the secretion efficiency of exogenous proteins is screened and engineered for enhanced scalability and versatility. Leveraging this platform, the prepared TOB-PslG-mOMVs nanoantibiotics, co-delivering glycosyl hydrolase (PslG) and tobramycin (TOB), synergistically disrupt biofilms and demonstrate potent antibacterial effects against Pseudomonas aeruginosa. Additionally, the prepared FI-mOMVs nanovaccines displaying the OprF_190-342-OprI_21-83 antigenic epitope fusion protein (FI) of P. aeruginosa can effectively induce robust humoral immune and cellular immune responses and significantly enhance protection against bacterial infection. Therefore, the OMVs nanoplatform thus represents a transformative approach, opening new avenues for combating multi-drug-resistant bacteria through innovative nanoantibiotic and nanovaccine technologies.