Abstract
In recent years the advent and spread of diverse multidrug-resistant bacteria has become a serious concern not only in the medical field but also in public health. The dissemination of drug-resistant pathogens has been considerably hastened by human activities in the clinical practice, livestock, and aquaculture sectors. Therefore, there is an urgent need to explore novel classes of antimicrobial agents against resistant bacterial pathogens. Antimicrobial peptides (AMPs), or host defense peptides, are synthesized by ribosomal or non-ribosomal mechanisms, which are vital components of the innate immune system in fish. Fish epidermal mucus can serve as a source of unique peptides with a broad range of biological activities including antimicrobial activity towards multidrug-resistant pathogens, anticancer, wound healing, etc. AMPs derived from epidermal mucus are recognized as a novel class of antibiotics owing to their inimitable and multidimensional effects, including the low possibility for developing antimicrobial resistance, minimal cytotoxicity towards mammalian cells, high selective cytotoxicity against pathogens, low residual flesh, and the capacity to modulate the host immune responses. Additionally, the mucosal composition varies among fish species and is influenced by both endogenous and exogenous factors, which could be leveraged to identify new drugs in the future. This review investigates the AMPs produced by aquatic fish, their unique properties as potent therapeutic agents as well as classifications and biological activities.