Emerging Threat of Vibrio alginolyticus in Mediterranean Aquaculture: Virulence, Antibiotic Resistance, and Innovative Control Strategies

Vibrio alginolyticus is an opportunistic marine pathogen increasingly associated with disease outbreaks in Mediterranean aquaculture, affecting fish, shrimp, and shellfish. The semi-enclosed nature of the Mediterranean Sea, combined with rising seawater temperatures and intensive farming practices, creates favorable conditions for the persistence and spread of Vibrio alginolyticus. This review explores the bacterium’s major virulence mechanisms, including biofilm formation, quorum sensing (QS), adhesion, and antimicrobial resistance (AMR). The widespread use of antibiotics in Mediterranean aquaculture has contributed to the emergence of resistant strains and environmental contamination, underscoring the urgent need for sustainable alternatives. Promising control strategies include phage therapy supported by the isolation of numerous lytic phages and vaccination, which, even in autogenous formulations, can reduce antibiotic dependence. Probiotics, particularly Bacillus and Lactobacillus species, enhance host immunity and larval survival through competitive exclusion and immune modulation. The interplay between QS, biofilm resilience, and phage–host dynamics highlights the complexity of Vibrio alginolyticus pathogenesis in this region. Integrating genomic tools, proteomics, and advanced diagnostics within a Mediterranean-specific framework will be crucial for sustainable disease management and food security.