Enhanced control of pathogenic Vibrio spp. in aquaculture using phages capable of disrupting biofilms outside their host range

ABSTRACT Vibrio species are among the most devastating pathogens in aquaculture, causing substantial economic losses. Their capacity to form resilient, often multispecies biofilms confers exceptional resistance to conventional antimicrobials. While bacteriophages represent a promising alternative for combating biofilm-associated infections, phages exhibiting potent antibiofilm activity against Vibrio spp. remain scarce. In this study, we isolated and characterized two novel lytic phages, VpT and VpR, specific to multidrug-resistant Vibrio parahaemolyticus . Genomic and phylogenetic analyses identified VpT and VpR as members of a novel viral family and a novel species within the class Caudoviricetes , respectively. Remarkably, beyond exhibiting potent biofilm prevention and disruption capabilities against their host strains, both phages effectively degraded preformed biofilms by eight non-host Vibrio species as well as complex multi-species Vibrio communities. This host range-independent, cross-species biofilm degradation activity highlights their potential for controlling complex polymicrobial biofilms. Moreover, VpT and VpR appear to employ distinct infection strategies, and when applied as a cocktail, they synergistically enhanced antimicrobial efficacy by suppressing bacterial regrowth, thereby addressing a key limitation of phage therapy. Our findings establish these phages as promising biocontrol agents against Vibrio infections and biofilm-associated challenges in aquaculture systems. IMPORTANCE The effective control of Vibrio infections in aquaculture remains a major challenge, largely due to the resilience of multispecies biofilms against conventional antimicrobial treatments. This study identifies two novel lytic phages, VpT and VpR, which not only prevent and disrupt biofilms formed by phage-sensitive, multidrug-resistant Vibrio parahaemolyticus but also degrade preformed biofilms of multiple phage-insensitive Vibrio species and complex mixed-species Vibrio communities. Notably, their distinct and synergistic infection mechanisms enhance antimicrobial efficacy by suppressing bacterial regrowth, thereby addressing a critical limitation of current phage therapies. These findings underscore the strong potential of these phages as next-generation biocontrol agents for combating complex Vibrio biofilms and enhancing pathogen control in aquaculture systems.