An Outbreak of Municipal Water-Associated Food Poisoning Caused by Salmonella Enteritidis

An outbreak of municipal water-associated food poisoning by Salmonella Enteritidis occurred in Takatoh Town. Nagano prefecture during September 4 to 19, 1989. The major symptoms observed in the 680 patients consisted of diarrhea (70.9%), abdominal pain (51.2%), fever (44.6%), headache (27.9%), nausea (5.9%) and vomiting (5.7%). In the outbreak, S. Enteritidis was the only suspected etiological agent isolated from both patients and municipal water supply. All of the 21 isolates were lysine decarboxylase activity negative. In other respects, the isolates conformed to the general characteristics of Salmonella. All of them were further characterized by phagovar 8 type, uniform drug susceptibilities and carrying 2.7 kb plasmid. Inspite of the evidence that the infection caused by a peculiar strain linked to the strain in municipal water supply used by the patients, it was impossible to determine the exact source of contamination in the water. The outbreak above seems to be the most large-scale among those of Salmonella found poisoning associated with drinking water in Japan.