Experimental Corynebacterium pseudotuberculosis infection in lambs.

Lambs were inoculated IV with 3.2 X 10(3) colony forming units (CFU) to 3.2 X 10(6) CFU of Corynebacterium pseudotuberculosis from a 6-hour broth culture supplemented with 0.1% sorbitan monooleate. After 28 days, multiple abscesses were observed in the lungs and lymph nodes. The number of abscesses in the lungs correlated with the inoculation dose. Two lambs given 10(5) CFU and 10(6) CFU died. Multiple abscesses occurred in other lambs given 10(6) CFU to 10(4) CFU and few abscesses occurred in lambs given 10(3) CFU. Corynebacterium pseudotuberculosis was isolated from lung abscesses, inoculation site abscesses, and lymph node abscesses, but not from normal tissues. Because this procedure consistently induced abscesses in the lungs, we believe it will be a suitable challenge system for studies on the prevention of caseous lymphadenitis in sheep.