Studies on Erysipelothrix Insidiosa S. Rhusiopathiae: 2. Serological Study

Sixty-two strains of E. insidiosa isolated from joints or regional lymph nodes of pigs with arthritis were examined for their antigenic characteristics. HCl and CH₃COOH extracts were made from all strains and precipitation tests performed with these extracts and rabbit anti-sera for types A₁, A₂, B₁, B₂, C, D, E, and G.The type distribution of the strains was as follows: 1 belonged in type A, 46 in type B, while 15, which did not contain demonstrable acid-soluble antigen, were designated N strains. The 46 type B strains could be divided into 4 subtypes on the basis of the patterns of reaction between, on the one hand HCl and CH₃COOH extracts, and, on the other hand, B₁ and B₂ sera. Thirty-two strains reacted with both B₁ and B₂ sera in CH₃COOH extracts, but not in HCl extracts; these strains were referred to a new subtype, B₃. Nine strains, which reacted with B₁ serum in HCl and CH₃COOH extracts and with B₂ serum in CH₃COOH extracts only, were referred to subtype B₁. Four strains that reacted with B₁ and B₂ sera in both extracts were referred to subtype B₂. The only representative of the 4th subtype was an interesting strain which in previous studies had been shown to differ from the rest of the strains in other ways, too. This strain reacted with both B₁ and B₂ sera, but only in HCl extract.