Usefulness of molecular genetic markers in the typing of Salmonella enterica serovar Enteritidis causing a food-borne outbreak.

A combination of serotyping-phagetyping and three molecular genetic markers (plasmid analysis, chromosomic DNA restriction pattern and ribosomal RNA gene restriction pattern or ribotyping) was used in the typing of Salmonella enterica causing a food-borne outbreak. The isolates analysed, 29 from stools and eight from foods, belonging to serovar Enteritidis-phagetype A, carried a 36-MDa plasmid, showed a similar DNA restriction pattern and the same ribopattern. These data indicate that only one strain was involved. The DNA pattern and ribopattern of this strain were indistinguishable from the patterns of a serovar Enteritidis-phagetype A strain which has caused salmonellosis in Asturias, Spain, since, at least, 1984.