Streptococcus Iniae in Lates Calcarifer

Lates calcarifer, also known as Barramundi or Asian seabass, is a highly productive and fast-growing species that is well suited to large-scale aquaculture due to its attractive harvestable yields (premium fish). This fish has been envisioned as having the potential to be the "Salmon of Tropics". Cultivating L. calcarifer in aquaculture poses challenges as the dense populations that make such aquaculture commercially viable facilitates the rapid spread of infectious diseases, which in turn significantly impact yield. Hence, immunization of juveniles is necessary and the development of new immunization agents enhances the efficiency of aquaculture and improves food security. In our study we characterize 7 novel strains of the bacterial pathogen Streptococcus iniae that were collected from commercial fish farms in Singapore and Australia. We demonstrate that inoculation with inactivated strain P3SAB cross-protects L. Calcarifer against S. iniae infections in vivo from a variety of strains found in both Singapore and Australia.