Classification position and virulence of Streptococus iniae strains isolated from seabass raising in Khanh Hoa province

Abstract

From 163 seabass samples suspecting Streptococcus infection, we identified 142 bacterial strains, they were determined to be Streptococcus iniae by using PCR method. The result of sequencing 16S rRNA gene of three S. iniae isolated strains in Khanh Hoa in 2018, 2019 and 2020 showed that similarity level of these bacteria strains was 98.42% - 99.86% compared to S. iniae in the GenBank. The 3/3 isolated strains carried high virulence, killed 100% the experimental fish (Lates calcarifer) within 24-72 hours. This studied result can be used for further researchs on developing vaccines
against S. iniae in seabass.