title: A large outbreak of enterohaemorrhagic Escherichia coli O157, caused by low-salt pickled Napa cabbage in nursing homes, Japan, 2012.
abstract: OBJECTIVE
  In August 2012, an outbreak of enterohaemorrhagic Escherichia coli (EHEC) O157 infection was investigated by the City of Sapporo and Hokkaido Prefectural Government. The initial notification reported an illness affecting 94 residents of 10 private nursing homes distributed across multiple areas of Hokkaido, the northernmost island of Japan; at this time three cases were confirmed as EHEC O157 infection. The objectives of the investigation were to identify the source of infection and recommend control measures to prevent further illness.
  
  
  METHODS
  A suspected case was defined as a resident of one of the private nursing homes in Hokkaido who had at least one of the following gastrointestinal symptoms: diarrhoea, bloody stool, abdominal pain or vomiting between 10 July and 10 September 2012. Cases were confirmed by the presence of Shiga toxin 1- and 2-producing EHEC O157 in stool samples of suspected cases. We conducted an epidemiological analysis and an environmental investigation.
  
  
  RESULTS
  We identified 54 confirmed and 53 suspected cases in 12 private nursing homes including five fatalities. Of the 107 cases, 102 (95%) had consumed pickles, all of which had been manufactured at the same facility. EHEC O157 isolates from two pickle samples, 11 cases and two staff members of the processing company were indistinguishable. The company that produced the pickles used inadequate techniques to wash and sanitize the vegetables.
  
  
  CONCLUSIONS
  Contaminated pickles were the likely source of this outbreak. We recommended that the processing company improve their methods of washing and sanitizing raw vegetables. As a result of this outbreak, the sanitation requirements for processing pickles were revised.
authors: Field Epidemiology Training Programme of Japan, National Institute of Infectious Diseases, Tokyo, Japan .
authors: Ayako
authors: A
authors: Tabuchi
authors: Field Epidemiology Training Programme of Japan, National Institute of Infectious Diseases, Tokyo, Japan .
authors: Taku
authors: T
authors: Wakui
authors: Infectious Diseases Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan .
authors: Yuichiro
authors: Y
authors: Yahata
authors: Public Health Office, City of Sapporo, Japan .
authors: Koichi
authors: K
authors: Yano
authors: Public Health Office, City of Sapporo, Japan .
authors: Kotaro
authors: K
authors: Azuma
authors: Infectious Diseases Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan .
authors: Takuya
authors: T
authors: Yamagishi
authors: Infectious Diseases Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan .
authors: Kazutoshi
authors: K
authors: Nakashima
authors: Infectious Diseases Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan .
authors: Tomimasa
authors: T
authors: Sunagawa
authors: Infectious Diseases Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan .
authors: Tamano
authors: T
authors: Matsui
authors: Infectious Diseases Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan .
authors: Kazunori
authors: K
authors: Oishi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001937:Brassica / Q000382:microbiology*; D003967:Diarrhea / Q000382:microbiology; D004196:Disease Outbreaks; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D005260:Female; D057141:Food, Preserved / Q000382:microbiology*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D009735:Nursing Homes; D012965:Sodium Chloride
chemical_list: D012965:Sodium Chloride