Streptococcus dysgalactiae, the long recognized mammalian pathogen, has currently received a major concern regarding fish bacterial infection. S. dysgalactiae caused either an opportunistic infection in immunocompromised patients or invasive infection in individuals handling livestock and seafood. The infected fish revealed systemic pyrogranulomatous inflammation with a severe necrotic lesion in their caudal peduncles. Despite increased clinical significance, the characterization of S. dysgalactiae strains isolated from different fish species collected in many countries and the...