Characterization of enterohemorrhagic Escherichia coli O111 and O157 strains isolated from outbreak patients in Japan.
In April and May 2011, there was a serious food-poisoning outbreak in Japan caused by enterohemorrhagic Escherichia coli (EHEC) strains O111:H8 and O157:H7 from raw beef dishes at branches of a barbecue restaurant. This outbreak involved 181 infected patients, including 34 hemolytic-uremic syndrome (HUS) cases (19%). Among the 34 HUS patients, 21 developed acute encephalopathy (AE) and 5 died. Patient stool specimens yielded E. coli O111 and O157 strains. We also detected both EHEC O111 stx2 and stx-negative E. coli O111 strains in a stock of meat block from the restaurant. Pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem-repeat analysis (MLVA) showed that the stx-negative E. coli O111 isolates were closely related to EHEC O111 stx2 isolates. Although the EHEC O157 strains had diverse stx gene profiles (stx1, stx2, and stx1 stx2), the PFGE and MLVA analyses indicated that these isolates originated from a single clone. Deletion of the Stx2-converting prophage from the EHEC O111 stx2 isolates was frequently observed during in vitro growth, suggesting that strain conversion from an EHEC O111 stx2 to an stx-negative strain may have occurred during infection.
Toyama Institute of Health, Toyama, Japan masanori.watahiki@pref.toyama.lg.jp.
Masanori
M
Watahiki
Toyama Institute of Health, Toyama, Japan.
Junko
J
Isobe
Toyama Institute of Health, Toyama, Japan.
Keiko
K
Kimata
Toyama Institute of Health, Toyama, Japan.
Tomoko
T
Shima
Toyama Institute of Health, Toyama, Japan.
Jun-ichi
J
Kanatani
Toyama Institute of Health, Toyama, Japan.
Miwako
M
Shimizu
Fukui Prefectural Institute of Public Health and Environment Science, Fukui, Japan.
Akihiro
A
Nagata
Ishikawa Prefectural Institute of Public Health and Environmental Science, Ishikawa, Japan.
Keiko
K
Kawakami
Yokohama City Institute of Health, Kanagawa, Japan.
Mikiko
M
Yamada
National Institute of Infectious Diseases, Tokyo, Japan.
Hidemasa
H
Izumiya
National Institute of Infectious Diseases, Tokyo, Japan.
Sunao
S
Iyoda
National Institute of Infectious Diseases, Tokyo, Japan.
Tomoko
T
Morita-Ishihara
National Institute of Infectious Diseases, Tokyo, Japan.
Jiro
J
Mitobe
National Institute of Infectious Diseases, Tokyo, Japan.
Jun
J
Terajima
National Institute of Infectious Diseases, Tokyo, Japan.
Makoto
M
Ohnishi
Toyama Institute of Health, Toyama, Japan.
Tetsutaro
T
Sata
D016000:Cluster Analysis; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D054324:Enterohemorrhagic Escherichia coli / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D019143:Evolution, Molecular; D005243:Feces / Q000382:microbiology*; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000382:microbiology*; D005838:Genotype; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008460:Meat / Q000382:microbiology*; D018598:Minisatellite Repeats; D017720:Molecular Epidemiology; D058889:Molecular Typing; D065288:Serogroup; D022603:Shiga Toxins / Q000235:genetics
D022603:Shiga Toxins