FIG. 4.

Southern hybridization of three strains: lane 1, Salmonella serovar Muenchen (human origin, p3633, R type ACSSuTAxKGCfCro); lane 2, Salmonella serovar Typhimurium (porcine origin, pUCE15, R type AKSSuT); lane 3, Salmonella serovar Muenchen (porcine origin, pUCE6, R type ACSSuTAxK), and lane M, molecular size marker. A DIG-labeled acetylphosphotransferase gene (aphA1-Iab) was used. Both MDR Salmonella serovar Typhimurium and MDR Salmonella serovar Muenchen isolates of porcine origin had the gene on the same restriction fragment, which was 9.5 kb.