Isolation of previously unreported serotypes of Erysipelothrix rhusiopathiae from swine

Serologic, biochemical, and pathogenic characteristics of 11 porcine isolants of Erysipelothrix rhusiopathiae that could not be placed in any of 16 established serotypes, were examined. On the basis of double-diffusion percipitin reactions, isolants were divided into 4 serologic variants, given serotype designations 17, 18, 19, and 20. Biochemical activity of the isolants was typical of E rhusiopathiae. One or more isolants of each serologic variant were pathogenic for both mice and swine.