Outer Membrane Vesicle Production by Escherichia coli Enhances Its Defense against Phage Infection

Several studies have investigated the multifunctional characteristics of outer membrane vesicles (OMVs), but research on their role in mediating phage–bacteria interactions is limited. Employing Escherichia coli as a model, we engineered a mutant strain overproducing OMVs for protective experiments against phage infections. The addition of exogenous OMVs proved highly effective in safeguarding the bacterial host against various phages, mitigating predatory threats. Screening for phage-resistant strains and adsorption experiments revealed that inhibiting phage adsorption is a crucial pathway through which OMVs protect against phage predation. Although OMVs conferred tolerance to the phage-sensitive strains (those easily infected by phages), they could not restore the phage-resistant strains (those that effectively resist phage infection) to a sensitive phenotype. This study provides valuable insights for the future development of novel biotechnological approaches aimed at utilizing OMVs to protect fermentative strains and reduce the risk of phage contamination.