PLASMID DIVERSITY IN SALMONELLA-ENTERITIDIS OF ANIMAL, POULTRY, AND HUMAN-ORIGIN

One hundred thirty-eight isolates of Salmonella enteritidis from human, animal, and avian species were analyzed for the presence of plasmid DNA. Plasmid DNA from S. enteritidis isolates were extracted by a modification of a high alkaline extraction procedure. Comparisons were made between samples based on the number of plasmids present and their molecular weights. There were seven different profiles seen among the 15 human isolates from the Centers for Disease Control. These seven profiles were recognized with the animal isolates from the National Veterinary Services Laboratory, the chicken isolates from the northeastern (NE) region of the United States, and the turkey isolates from Minnesota (MN). There were no shared profiles between the human isolates and the chicken isolates from MN. The greatest relationship existed between the human isolates and the chicken isolates from the NE region of the United States, sharing four common profiles. Every Centers for Disease Control isolate shared a plasmid profile with chicken isolates from the NE region of the United States. The chicken isolates from MN had no profiles in common with any isolates from any other groups. The majority of animal isolates from National Veterinary Services Laboratory and the turkey isolates from MN possessed the virulence-associated 54 kb plasmid alone. This paper describes how plasmid profiles can be used as a tool in epidemiological investigations.