Escherichia coli outer membrane vesicles: Bacterial virulence, antibiotic resistance, host interactions, and applications in biomedical platforms.

Escherichia coli is a clinically significant Gram-negative pathogen, and the emergence of multidrug-resistant and highly virulent strains poses a grave threat to public health. Outer membrane vesicles (OMVs) are spherical nanostructures secreted by Gram-negative bacteria and composed of the outer membrane and a suite of encapsulated bioactive components, including proteins, lipopolysaccharides, and nucleic acids. Research indicates that OMVs play pivotal roles in pathogenic mechanisms, antimicrobial resistance transmission, and host-pathogen interactions. This review systematically elucidates the biogenesis mechanisms and molecular composition of E. coli OMVs while thoroughly examining their core biological functions in virulence, resistance, and immune modulation. Additionally, this review evaluates the translational potential of OMVs in vaccine development, biomolecular delivery, and tumor therapy. In summary, a comprehensive understanding of the biological properties and functions of E. coli OMVs is crucial for developing innovative OMV-based strategies for infection control, diagnosis, and therapy, thereby providing valuable directions for future research.