Microscopic Agglutination Test (MAT) described as a diagnostic test for Leptospirosis was used to check antigenicity on 47 samples of Arcobacter cryaerophilus and two samples of Arcobacter butzleri isolated from pigs in Rio Grande do Sul, Brazil. Rabbit antisera used in the test were produced against reference strains of Arcobacter spp. Antigenic heterogenicity among the samples was shown. Only four samples provoked titres higher than 1.600 with standard antisera. 48.97% of the antigens confirmed the genetic classification of the microrganisms. MAT was used also to identify serum samples from sows with reproductive problems from farms where Arcobacter spp had been isolated. There is no reference in the literature on the use of the test as diagnostic tool in Arcobacter infections. Serologic tests in sows showed titres as high as 1,600, suggesting that there was presence of agglutinins in serum samples.
antigenic diversity; microscopic agglutination test; Arcobacter spp; pigs