Vibrio alginolyticus: an emerging marine pathogen at the intersection of aquaculture, public health, and antimicrobial resistance

Abstract

Vibrio alginolyticus is a halophilic, Gram-negative marine bacterium that has emerged as a significant opportunistic pathogen affecting both marine animals and humans. As one of the most abundant vibrios in coastal and estuarine environments worldwide, V. alginolyticus causes substantial economic losses in aquaculture through vibriosis in fish, shrimp, and shellfish, while also being responsible for wound infections, otitis externa, and occasionally gastroenteritis in humans following seawater exposure or seafood consumption. The pathogenesis of V. alginolyticus is multifactorial, involving an arsenal of virulence determinants including secretion systems (type III, type VI, and type II), haemolysins, adhesins, biofilm formation, quorum sensing-regulated factors, and the recently recognized contributions of non-coding RNAs and outer membrane vesicles. Recent genomic analyses have revealed considerable genetic diversity among isolates and identified a ubiquitous presence of β-lactam resistance genes, raising concerns about natural resistance and the potential for horizontal gene transfer. The interplay between rising seawater temperatures, intensive aquaculture practices, and increasing antimicrobial resistance has positioned V. alginolyticus as an emerging pathogen of growing concern. This Review synthesizes current knowledge on the epidemiology, genomics, virulence mechanisms, host interactions, and control strategies of V. alginolyticus , with an emphasis on the molecular determinants of pathogenesis, including the regulatory networks governing adhesion, biofilm formation, and metabolic adaptation, and the challenges posed by antimicrobial resistance. We also discuss promising alternative control approaches, including phage therapy, vaccination, and probiotic strategies, and identify key knowledge gaps that warrant future investigation.