Biochemical and molecular typing of Streptococcus iniae isolated from fish and human cases

Streptococcus iniae is an important bacterial pathogen of fish, causing up to 50% mortality in stocks, which has recently been associated with human infections. To determine whether S. iniae isolates from humans and fish are similar, the present authors examined the biochemical profiles and genetic relatedness of these isolates by random amplified polymorphic DNA (RAPD) analysis and repetitive primer polymerase chain reaction(REP PCR). The biochemical profiles differentiated between the human and fish isolates of S. iniae using pyrrolidonyl arylamidase, arginine dehydrogenase, ribose, β‐glucoronidase and glycogen as markers. These biochemical results suggest that the fish and human S. iniae isolates are genetically different. However, RAPD and REP PCR do not have the discriminatory power to differentiate between these streptococcus isolates using five different RAPD primers and BoxA primer.