Outer membrane vesicles in Vibrio species: Roles in biofilm formation and pathogenesis

Outer membrane vesicles (OMVs) have been increasingly recognized as common mediators of bacterial physiology in Gram-negative bacteria, including Vibrio species. The degree and function of OMV production can differ among strains and even within a single species. The secretion of OMVs is a prevalent trait among many Vibrio species, particularly in pathogenic organisms such as Vibrio cholerae, Vibrio vulnificus, and Vibrio parahaemolyticus. The OMVs released by these organisms are often associated with infection, transport of virulence factors into host cells, defense against stress, biofilm formation, flagella rotation, transportation of active enzymes, signaling molecules in the surrounding environment, and facilitating bacterial translocation. All of these are advantageous to the bacteria. These OMVs also possess immunogenic properties that regulate the innate and adaptive immune responses, which are beneficial to host cells. Few species, such as Vibrio ordalii, Vibrio coralliilyticus, Vibrio natriegens Vibrio alginolyticus, and Vibrio europaeus, have been recently studied for the first time that secrete OMVs; future research is necessary to determine any other activities that these vesicles may possess beyond those that are now documented.