A Rapid Agglutinating Antibody-detection Method for the Diagnosis of Streptococcus dysgalactiae Infection in Farmed Fish Using Recombinant Surface Immunogenic Protein (rSd-Sip) -coated Latex Beads

Abstract

To develop a rapid diagnosis method for Lancefield group C Streptococcus dysgalactiae (GCSD) infection, latex beads were coated with recombinant S. dysgalactiae surface immunogenic protein (rSd-Sip). The usefulness of the beads for slide agglutination tests with fish sera was examined. The beads were agglutinated with GCSD-infected sera collected from farmed amberjack Seriola dumerili. However, the beads were not agglutinated with non-infected sera or immunized sera collected from fish vaccinated with Lactococcus garvieae and Streptococcus iniae. The results demonstrate that the slide agglutination test using rSd-Sip-coated latex beads is an easy, rapid, and effective method for agglutinating antibody-detection in GCSD-infected fish.