PFGE analysis of Salmonella Braenderup isolates from two districts, September-November 1999 - Hyogo
(IASR 2000; 21: 9-10)

During September to November 1999, 22 children (age 0-8 years old) presented diarrhea, and they visited pediatricians in Himeji city. Salmonella Braenderup was isolated from 6 patients' stool (Table1, cluster A). In the beginning of November, 4 diarrheal children (age 3-11 years old) from T town and I town in Awaji Island yielded Salmonella O7 from stool. These isolates were identified as Salmonella Braenderup by the Hyogo Prefectural Institute of Public Health (Table1, cluster B). In the beginning and middle of November, the Hyogo Prefectural Sumoto Health Center carried out stool examination to food handlers working at 4 facilities of kindergarten and elementary school in S city, N town, and T town in Awaji Island. Of 69 stool samples, 14 were positive for Salmonella, and 9 of them were Salmonella Braenderup (Table 1, cluster C). Eighty-nine samples, which were concurrently collected from 8 facilities in S city, N town, and M town, were all negative for Salmonella.

These 19 isolates were examined with pulsed-field-gel-electrophoresis (PFGE) using Bln I and Xba I. Results indicated that DNA fragment patterns were obviously different between those isolated from Himeji city and Awaji Island (Figure 1). However, those patterns of the patients and the food handlers in Awaji island were identical to a patient's in Himeji city. The PFGE pattern of the food poisoning in 1991 did not match with any patterns. Stool examination to food handlers has been carried out biweekly, so that this incidence seemed to be transitory. Regarding with the same PFGE pattern among the patients and food handlers in Awaji Island, implicated food is not identified yet.

Geographically Awaji Island and Himeji city is no adjacent, thus frequent person-to-person contact is unbelievable. But some common foods might have been consumed in the areas. It remains to be seen that these isolates are derived from a common strain, because genomic difference is obvious. Considering that one of 6 patients' clones in Himeji city was identical with the Awaji strain, we speculate that these isolates have the original clone, either from the Awaji strain or one of 5 Himeji strains and evolved through 2 subclones.

Reported by Kokichi Hamada, Hidetaka Tsuji, The Hyogo Prefectural Institute of Public Health; Etsuko Sego and Shinzo Maeda, The Hyogo Prefectural Sumoto Health Center.

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