Bacterial diseases, including antimicrobial resistance, are emerging threats to both human as well as animal health. Incidences of bacterial disease outbreaks in aquaculture have increased with the intensification of the aquaculture systems and extensive use of antibiotics that accelerate the emergence of AMR strains. As such, an alternative to antibiotics is highly sought in the aquaculture industry.
Project AquaPhage aims to explore and develop a strategy for the potential use of bacteriophage (or phages, a friendly virus that selectively kills bacteria) to control bacterial disease outbreaks in aquaculture systems minimizing and/or replacing the use of antibiotics.
To achieve our goal, we used metagenomics data to study the diversity of phages in hatchery systems using bioinformatic tools SqueezeMeta and MetaPhage and then identified the potential source of phages followed by isolating phages, particularly against various species of Vibrio.
Our metagenomics (N=5) results of hatchery ponds show that diverse lytic and lysogenic phages are important parts of the hatchery system. Altogether 29 complete phage genomes were recovered from the metagenomes. The most abundant phages were Caudovirales and most of them (~73%) were against Gram-negative bacteria. Further, we identified different Vibrio species (N=29) from the hatchery environment using 16S rRNA PCR. So far, using the identified bacteria as hosts, we have successfully isolated 2 phages against 2 different hosts. One of the phages had strong lytic activity against the host Vibrio suggestive of lytic phage while the other had faint plaques suggestive of lysogenic phage. In future, we aim to fully characterize the phages and investigate their potential application in the biocontrol of Vibriosis and also elucidate mechanisms of phage-host co-evolution.