Mechanisms Driving Antimicrobial Resistance in Aquaculture

Aquaculture is a rapidly growing industry, with worldwide production reaching new levels. Intensive aquaculture often leads to the occurrence of bacterial diseases, which cause large economic losses. Antibiotics are the first choice for the treatment of these diseases, but their frequency or improper use results in the development of antimicrobial resistance. The aim of this study was to present the mechanisms of antimicrobial resistance to the most widely used groups of antibiotics, such as quinolones, tetracyclines, and phenicols, for controlling bacterial diseases in fish. The selective pressure exerted by these pharmaceuticals drives the emergence of resistant bacterial strains and the horizontal transfer of genes encoding this resistance. The transmission of resistant pathogens from aquaculture to other animals and humans is well documented, which complicates the treatment of emerging bacterial diseases. Hence, the aquatic environment is a major reservoir of resistant bacteria, genes, and antimicrobials. Efforts should be made to stop the excessive and improper use of antibiotics in aquaculture and encourage farmers to use alternative means for the prevention and control of bacterial diseases. Several alternative strategies can be employed in aquaculture as substitutes for antibiotics, thereby mitigating the development of antimicrobial resistance. Among the most prominent alternative measures are vaccines, immunostimulants, and bacteriophage therapy. Encouraging the adoption of sustainable farming practices plays a critical role in fostering optimal conditions for aquaculture systems, thereby mitigating disease outbreaks and obviating the need for antibiotic treatments. Antimicrobial resistance is effectively mitigated through the implementation of a holistic One Health approach, which systematically curtails the emergence and dissemination of resistant bacteria while safeguarding human and animal health.