RESUMEN
Among the major bacterial secretions, outer membrane vesicles (OMVs) are significant and highly functional. The proteins and other biomolecules identified within OMVs provide new insights into the possible functions of OMVs in bacteria. OMVs are rich in proteins, nucleic acids, toxins and virulence factors that play a critical role in bacteria-host interactions. In this review, we discuss some proteins with multifunctional features from bacterial OMVs and their role involving the mechanisms of bacterial survival and defence. Proteins with moonlighting activities in OMVs are discussed based on their functions in bacteria. OMVs harbour many other proteins that are important, such as proteins involved in virulence, defence, and competition. Overall, OMVs are a power-packed aid for bacteria, harbouring many defensive and moonlighting proteins and acting as a survival kit in case of an emergency or as a defence weapon. In summary, OMVs can be defined as bug-out bags for bacterial defence and, therefore, survival.