RESUMEN
Seventeen Serpulina hyodysenteriae strains isolated from faeces, rectal swabs and intestinal contents of pigs with Swine Dysentery, from farms located in Buenos Aires province were serotyped. Samples on selective media (trypticase soy agar added by 5% ovine blood, 400 mg/l spectinomicin, 30 mg/l colistin, 30 mg/l vancomycin) were streaked and incubated under anaerobic atmosphere for 72 h at 42 degrees C. Suspected S. hyodysenteriae growth were identified by strong beta-hemolytic zone, without colonies, and the spirillar morphology, using the Victoria Blue 4-R stain were criteria following by S. hyodysenteriae preliminar identification. The following antigens were made by phenolic extraction from a concentrated inocula washed twice in PBS pH 7: whole-cell (WC), boiled cell (BC) and lipopolysaccharide (LPS). Two serological test were: coagglutination and immunodiffusion, using polyclonal rabbit antisera against the 9 serotypes of S. hyodysenteriae and S. innocens, using WC and BC like antigens for the first test and BC and LPS for the second. The Dot-ELISA Test was performed using BC and LPS antigens and monoclonal antibodies (AbM) against serotypes 1, 2, 3, 8, 9 of S. hyodysenteriae, AbM species-specific and AbM against S. innocens. All isolated S. hyodysenteriae strains belonged to serotype 8. Like in other countries occurred, it would exit a high regional prevalence of S. hyodysenteriae serotype, being the serotype 8 in Argentine.