We examined the antimicrobial resistance of 1,257 isolates of 30 serovars o
f Salmonella enterica subsp. enterica isolated from swine. Serovars Typhimu
rium and Typhimurium var. Copenhagen were widespread and were frequently mu
ltidrug resistant, with distinct resistance to ampicillin, kanamycin, strep
tomycin, sulfamethoxazole, and tetracycline and to ampicillin, chlorampheni
col, streptomycin, sulfamethoxazole, and tetracycline, respectively.