#NAME?The result of isolation and determination of the biological characteristics and antisera groups, of Salmonella spp. in pork in Lang Son province indicated that out of 90 pork samples collecting, in Lang Son (Gieng Vuong, Chi Lang, Dong Kinh pork retail markets), there were 12.22% of, samples contaminated with Salmonella spp. Of which, the highest contamination rate was in Chi, Lang market (16.67%), followed by Dong Kinh market (13.33%) and the lowest contamination, rate was in Gieng Vuong market (6.67%). The Salmonella contamination rate of pork increased, by the time after slaughter and seasons from winter to summer. The result of testing susceptibility, with antibiotics of 6 isolated bacteria strains indicated that the susceptible rate of bacteria strain, with ciprofloxacine was 83.33%, with enrofloxacine was 66.6%, with norfloxacine was 50%. All, of isolates resisted with tetracycline, and they were the high virulent strains, killing 100% of the, experimental animals within 24 - 48 hrs after injection. The isolates carried all the biological and, chemical characteristics of Salmonella bacteria genus, and the strains were determined, such as:, 5 strains belonged to S. typhimurium (45.45%)
3 strains belonged to S. welteveden (27.27%)
2, strains belonged to S. anatum (18.18%) and 1 strain belonged to S. schlleissheim (9.09%)