Abstract

Salmonella enterica subspecies enterica serovar Typhimurium is one of the common food pathogens which may cause human disease and/or animal infections. In an attempt to trace the clonal relationship and to discern the possible transmission of these strains from different origins, twenty-five Salmonella typhimurium strains isolated from retail meats and four strains isolated from food-poisoning cases were tested for antimicrobial resistance using the standard disk diffusion method. Pulsed-field gel electrophoresis was used to identify subtypes of these S. typhimurium strains. The results showed that in S.typhimurium high genetic similarity could exist. When plasmid profiles were combined with PFGE patterns, this combination further improves the discrimination of these strains. The strains of the same pattern combination may be the most epidemic strains which circulating between contaminated animal–derived meat and human. Transmission of these strains between different areas and origins might be possible.

Key words: Salmonella typhimurium, antimicrobial resistance, PFGE, plasmid profile.