Genome-free bacteria vaccine against motile Aeromonas septicaemia in tilapia (Oreochromis sp.)

Summary 

Aquaculture is a rapidly growing food-producing sector, accounting for 52% of the fish consumed globally in 2020 and generating over £200 billion in economic value. Low-and-middle income countries (LMICs) have become increasingly reliant on fishery trade, with an estimated 56.6 million people employed in the industry, with the vast majority (94%) located in Asia.

One of the most significant challenges facing the aquaculture industry is bacterial disease, which has costed the industry over £4.8 billion in loss-of-yield each year. One of the most common bacterial diseases affecting cultured aquatic organisms is motile Aeromonas septicaemia (MAS), caused by Aeromonas spp. MAS usually infecting cultured tilapia, catfish and carps causing up to 50-70% of mortality, where these species are highly cultured and consumed in LMICs.

Antimicrobial resistance (AMR) further complicates the treatment of this bacterial disease, as Aeromonas spp. is among the most reported AMR organisms in various fish species. As a result, treating these pathogens is becoming increasingly challenging and expensive, which puts the livelihoods of many aquafarmers in LMICs at risk.

To address this issue, this project aims to develop whole-cell bacterial vaccines using the SimCell technology. SimCells are genome-free bacterial cells produced by enzymatically shearing the bacterial genome, rendering the bacterium replication-deficient while preserving immunogenic cell-surface features. Developing SimCell vaccines against MAS could offer an effective solution for protecting fish from the pathogen, potentially reducing economic losses and supporting the livelihoods of small-scale farmers and fishing communities in LMICs.