Discrimination between virulent and nonvirulent Streptococcus suis type 2 strains by enzyme-linked immunosorbent assay.
Discrimination between virulent and nonvirulent strains of Streptococcus suis type 2 will allow proper diagnosis of diseased pigs and the identification of carrier pigs. To discriminate between virulent and nonvirulent strains, we developed two double antibody sandwich (DAS) enzyme-linked immunosorbent assays (ELISA) using specific monoclonal antibodies directed against two virulence markers of S. suis type 2. One mAb was directed against the 136-kilodalton (kDa) cell-wall-associated protein, designated muramidase-released-protein (MRP). The other mAb was directed against a 110-kDa extracellular protein, provisionally called extracellular factor (EF). We examined 179 strains of S. suis serotype 2, 22 strains of S. suis serotypes 1 to 22, 22 other streptococci, 20 other bacterial strains, and one yeast. The ELISA results were almost identical with western blot analysis of these strains. Visual readings of the two DAS-ELISAs were enough to discriminate accurately between the three phenotypes of S. suis type 2. We concluded that the two DAS-ELISAs are reliable, rapid, and simple assays to identify virulent strains of S. suis type 2.
Vecht
U
U
Department of Bacteriology, DLO-Central Veterinary Institute, Lelystad, Netherlands.
Wisselink
H J
HJ
Anakotta
J
J
Smith
H E
HE
D000818:Animals; D000911:Antibodies, Monoclonal; D015415:Biomarkers; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D017011:Streptococcus suis / Q000145:classification / Q000472:pathogenicity*; D013552:Swine; D014774:Virulence
D000911:Antibodies, Monoclonal; D015415:Biomarkers