Serious Threat of Antibiotic Resistance in Fish Microflora: A Critical Review

Abstract

Antimicrobial resistance (AMR) has emerged as one of the most serious biological threats affecting aquatic ecosystems, aquaculture sustainability, food security, and public health. The extensive use of antibiotics in aquaculture for therapeutic, prophylactic, and metaphylactic purposes has accelerated the selection of resistant microorganisms within fish-associated microbiota. Fish microflora, particularly the gut, gill, skin, and environmental microbial communities associated with culture systems, serve as reservoirs of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). These resistance determinants can spread through horizontal gene transfer, facilitating the emergence of multidrug-resistant pathogens with implications extending beyond aquatic environments. Recent studies have demonstrated the widespread occurrence of tetracycline, sulfonamide, quinolone, β-lactam, and aminoglycoside resistance genes in aquaculture systems worldwide. The dissemination of ARGs through water, sediments, feeds, fish products, and aquatic wildlife has strengthened concerns regarding the role of aquaculture in the global AMR crisis. Modern metagenomic investigations have further revealed the complexity of fish-associated resistomes and their connectivity with environmental and human-associated microbial communities. This review critically examines the development of antibiotic resistance within fish microflora, the mechanisms underlying resistance acquisition, global distribution patterns, ecological and public health implications, and emerging mitigation strategies. Emphasis is placed on the One Health framework, which recognizes the interconnectedness of human, animal, and environmental health in addressing AMR. Current evidence indicates that antibiotic resistance in fish microflora is no longer a localized aquaculture problem but a global environmental and public health challenge requiring coordinated international intervention.