Molecular Epidemiology ofSalmonellaEnteritidis Food Poisoning by Pulsed-Field Gel Electrophoresis

Abstract

During the years 1983 to 1999, a total of 120 Salmonella Enteritidis (SE) isolates from various sources, patient's stool, foods, kitchen wear, river water etc., in 61 cases of food poisoning in the Sakai City, were typed by pulsed-field gel electrophoresis (PFGE) after XbaI or NotI digestion of chromosomal DNA. XbaI and NotI restriction produced 2 (X1 and X2) and 3 (N1, N2 and N3) pulse-field profiles, respectively. The X1 and N1 types were further divided into 8 (Xla-Xlh) and 6 (N1a-N1f) subtypes, respectively. However, these strains of subtypes showed only 0-4 fragment changes in PFGE patterns and the index of discrimination of over 0.75, indicating that SE isolates belong to the same clonal lineage, or are revealing closely clonal relationships. These results suggested a possible strain transmission in case of food poisoning, and epidemiologically related SE isolates were spread in the Sakai City district during a long period.