[Bacterial infection in cows associated with abortion, endometritis and sterility]

Isolated were two types of bacteria (having common morphologic and cultural behaviour and related antigenic composition) from aborted fetuses and placentae of cows with a positive reaction after both Huddleson and placentae of cows with a positive reaction afterboth Huddleson and Wright. They were shown to be new species of the group Mimeae and the genus Yersinia. It was demonstrated through immunodiffusion and immunoelectrophoresis that these new bacteria present antigenic relationship with Brucella organisms. A common O-antigen determinant was found to exist in the isolated bacteria and the S-and R-Brucellae and Br. ovis. The pathogenic effect was tested of the newly isolated bacteria on experimental animals, establishing a certain degree of uterotropism. An abortion was reproduced in a pregnant heifer by means of the intravenous injection of a bacterial culture. The serologic reaction presented by the animal proved comparable with that of cows exhibiting a natural infection process.