Massive Outbreak of Escherichia coli O157: H7 Infection In Schoolchildren in Sakai City, Japan, Associated with Consumption of White Radish Sprouts

TLDR

In July 1996, an outbreak of Escherichia coli O157:H7 infected schoolchildren in 47 elementary schools across Sakai City, Osaka, Japan, with hospitalizations occurring between July 17 and 19 following symptom onset on July 8–9. The outbreak was traced to school lunches served on July 1 and 8 in the North‑East District and on July 1, 4, 8, and 9 in the Middle‑South District, where white radish sprouts from a single farm were the sole uncooked food shared by the most implicated meals. Pulse‑field gel electrophoresis showed identical patterns among isolates from Sakai and neighboring areas, confirming that the outbreak was caused by white radish sprouts shipped from that farm between July 7 and 9.

Abstract

In July 1996, an outbreak of Escherichia coli O157:H7 infection occurred among schoolchildren in Sakai City, Osaka, Japan. This outbreak developed in 13 North-East District and 34 Middle-South District elementary schools in the city. All children hospitalized on July 17-19 had presented on July 8 (North-East District) and July 9 (Middle-South District). School lunches served on July 1 and 8 in the North-East District and on July 1, 4, 8, and 9 in the Middle-South District were proposed by a food consumption study to be associated with infection. White radish sprouts from a single farm were the only uncooked food common to the most highly implicated meals on the involved days in two school districts (sweet and sour chicken with lettuce on July 8 in the North-East District and chilled Japanese noodles on July 9 in the Middle-South District). Two incidents of E. coli O157:H7 in neighboring areas were also related to white radish sprouts from the farm. The pulse-field gel electrophoresis patterns of isolates from patients in these two districts and the neighboring areas were identical. Thus, it was concluded that the cause of the outbreak was the white radish sprouts shipped on July 7-9 from one particular farm.