Hyperimmune sera against four strains of Corynebacterium pseudotuberculosis isolated from different animals (sheep, goat, buffalo and cattle) were obtained by inoculating rabbits with strains in different forms (live, dead plus live or dead). Immunization with live or dead bac teria followed by live strains gave similar results with regard to antibody titres and number of precipitin lines. Typing 21 strains of C. pseudotuberculosis by specific precipitin reac tions in agar gel was performed by

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... sing antigens extracted with sodium deoxycholate. The authors concluded that they were divisible into two serotypes, I and II. The nitrate reduction test and animal pathogenicity tests (by inocu lating guinea-pigs subcutaneously) demonstrated additional differences between the two types. Type I was nitrate negative, and produced local and general absces ses in guinea-pigs, with a prolonged course (15 days) ending fatally. It included all the strains originating from sheep and goats, but only 3 of 5 cattle strains. Type II comprised all 7 isolates from buffaloes and 2 of the cattle strains. All strains were nitrate positive and did not produce abscesses in guinea-pigs, but they caused tissue necrosis at the site of inoculation, with a rapid course (not more than five days) ending in death.