Morphological, biological and genomic characterization of lytic phages against Streptococcus agalactiae causing streptococcosis in tilapia.

Streptococcus agalactiae, a highly invasive pathogen causing streptococcosis, is a major disease imparting devastating effect in the aquaculture, worldwide. As bacteriophage therapy is getting more attention recently, as an alternative viable biocontrol agent to antibiotic and vaccine, this study aimed to isolate and purify obligately lytic bacteriophages and study its morphological, genetic and biological characteristics. Host range analysis of the four bacteriophages isolated in this study, such as Phage- 12 P, 15 F, 16 E and 20D exhibited 100% infectivity to S.