Bacterial Pathogenesis in Various Fish Diseases: Recent Advances and Specific Challenges in Vaccine Development

Abstract

Aquaculture is a fast-growing food sector but is plagued by a plethora of bacterial pathogens that infect fish. The rearing of fish at high population densities in aquaculture facilities makes them highly susceptible to disease outbreaks, which can cause significant economic loss. Thus, immunity development in fish through vaccination against various pathogens of economically important aquaculture species has been extensively studied and has been largely accepted as a reliable method for preventing infections. Vaccination studies in aquaculture systems are strategically associated with the economically and environmentally sustainable management of aquaculture production worldwide. Historically, most licensed fish vaccines have been developed as inactivated pathogens combined with adjuvants and provided via immersion or injection. In comparison, live vaccines can simulate a whole pathogenic illness and elicit a strong immune response, making them better suited for oral or immersion-based therapy methods to control diseases. Advanced approaches in vaccine development involve targeting specific pathogenic components, including the use of recombinant genes and proteins. Vaccines produced using these techniques, some of which are currently commercially available, appear to elicit and promote higher levels of immunity than conventional fish vaccines. These technological advancements are promising for developing sustainable production processes for commercially important aquatic species. In this review, we explore the multitude of studies on fish bacterial pathogens undertaken in the last decade as well as the recent advances in vaccine development for aquaculture.

Biofilm formation and auto-aggregation abilities of novel targeted aqua-probiotics

“…Fish vibriosis is widespread in the seas and brackish waters, affecting both marine and coastal freshwater fish of various species, including salmon, cod, eel, herring, perch, and flounder [71]. Along with fish vibriosis, Aeromonas septicemia, edwardsiellosis, columnaris and streptococcus, as well as a number of other diseases, are largely responsible for economic losses in aquaculture production [72][73][74][75][76][77][78][79][80][81][82][83][84].…”

Dissecting the heat stress altering immune responses and skin microbiota in fish in a recirculating aquaculture system in Singapore

“…The genera, Marinobacterium, Marivivens, Pseudoalteromonas, Pseudomonas, Tenacibaculum, and Vibrio had significantly increased relative abundance in moribund fish. Among these genera, Pseudomonas, Tenacibaculum, and Vibrio are well-known fish opportunistic bacteria that can cause infection (46)(47)(48). Notably, the microbiota of both fin and kidney had a slight decrease in relative abundance of Streptococcus, another genus that causes illness in barramundi (49,50).…”

Comprehensive Similarity Algorithm and Molecular Dynamics Simulation-Assisted Terahertz Spectroscopy for Intelligent Matching Identification of Quorum Signal Molecules (N-Acyl-Homoserine Lactones)

“…The deterioration of the aquatic environment and the development of intensive highdensity aquaculture models have resulted in the increased occurrence of aquatic bacterial diseases [1]. The sustainable development of modern aquaculture is significantly constrained by bacterial diseases.…”