Jpn. J. Infect. Dis., 58, 2005

Laboratory and Epidemiology Communications

An Outbreak of Food Poisoning Caused by an Enteropathogenic
Escherichia coli O115:H19 in Miyagi Prefecture
Noriyuki Saito*, Michi Kawano, Taeko Kobayashi, Setsu Watanabe, Waka Yamada,Juro Yatsu, Kazuo Kawamukai and Kazuo Akiyama
Miyagi Prefectural Institute of Public Health and Environment, Sendai 983-0836, Japan
Communicated by Haruo Watanabe(Accepted May 23, 2005)
period was 20 (19.4%), from 4 a.m. to 6 a.m. on the 10th, 14
individuals (13.6%) developed symptoms between 6 p.m. and8 p.m. on the 9th. Unfortunately, we could not determine thecausative common meal.
To identify the causative pathogens in the case, a total of
118 samples of 54 foods, 59 stool specimens from infectedindividuals, and 5 stool specimens from the food preparers wereinspected in our laboratory for bacteria such as diarrheagenic
E. coli, Shigella spp., Salmonella spp., Yersinia enterocolitica,
Campylobacter spp., Staphylococcus aureus, Bacillus cereus,
Clostoridium perfringens and Vibrio spp., and for viruses suchas norovirus, rotavirus, astrovirus, and adenovirus. As aresult, although 20 strains of E. coli O115 were isolated fromthe 59 stool specimens, other food poisoning bacteria andviruses were not isolated. The 20 isolated strains of E. coli
O115 were examined for their biochemical properties, H
serogrouping, antibiotic susceptibility, possession of virulent
factors and/or genes and pulsed-field gel electrophoresis(PFGE) analysis.
The main results of the isolates are shown in Table 1. The
biochemical properties of the isolates were shown to be thesame as those of typical E. coli, and H serotyping was H19.
The isolates were evaluated by PCR for identification of
the virulence genes of diarrheagenic E. coli. Although theisolates were positive for the eae gene by PCR, they were negative for stx1, 2, invE, ipaH, st, lt, aggR and astA (1). It was
herefore concluded that the isolates did not correspond toOutbreaks of mass food poisoning due to enteropathogenic
Escherichia coli (EPEC) have been rare in Japan.
In this report, we describe an outbreak of food poisoning
considered to have been caused by EPEC O115:H19 in 103
individuals at the site of a training camp in Miyagi Prefecturein August 2004.
On August 10, there was connection of the purport “highschool student plurality presents food poisoning symptoms
in a sports park, and were conveyed by the ambulance” at thejurisdiction public health and welfare office from the firefighting headquarters. An investigation initiated by the
public health and welfare office revealed that a total of148 persons, 131 students from 9 high schools and 17 gameleaders, gathered in a sports park at a summer camp 2 days
before. Among them, a total of 103 persons, including 100
students and 3 game leaders (attack rates of symptoms:69.6%), developed symptoms, such as stomachache (83%),
diarrhea (82%), nausea (27%), headache (24%), and fever(19%). Based on interviews of the infected individuals, theoutbreak was considered due to some cause other than direct
person-to-person transmission. The drinking water at the siteof the training camp was supplied by the waterworks, andcontained the proper concentration of chlorine. Since theinfected individuals had a common dinner on the 8th, anda common breakfast, lunch, and dinner on the 9th, it wassuspected that the food poisoning was caused by one of thesemeals. Although the greatest number of infections in one 2-hTable1. Properties of the isolated E. coli O115:H19
Items

Comments

Gram staining
Oxidase test
TSI agar
LIM agar
Pathogenic genes or factors

Gram-negative rod
NegativeA/A
Lysin (+), Indol (+), Motility (+)
lt (-), st (–), invE (–), ipaH (–), stx1 (–), stx2 (–),
aggR (–), astA (–), eae (+)
sensitive to all 17 antibiotics: ABPC, PIPC, CEZ,CTM, CAZ, CCL, FOMX, CPDX, AZT, IPM, MEPN,GM, AMK, MINO, FOM, LVFX, ST

Antibiotic susceptibility

ABPC, ampicillin; PIPC, piperacillin; CEZ, cefazolin; CTM, cefotiam; CAZ, cefrazidime;
CCL, cefaclor; FMOX, flomoxef ; CPDX, cefpodoxime; AZT, aztreonam; IPM, imipenem;
MEPN, meropenem; GM, gentamicin; AMK, amikacin; MINO, minocycline; FOM,fosfomycin; LVFX, levofloxacin; ST, sulfamethoxazole-trimethoprim.

*Corresponding author: Mailing address: Miyagi PrefecturalInstitute of Public Health and Environment, Saiwai-cho 4-7-2,Miyagino-ku, Sendai 983-0836, Japan. Fax: +81-22-257-7194,
E-mail: nsaito@ihe.pref.miyagi.jp189

Jpn. J. Infect. Dis., 58, 2005
cefotiam, ceftazidime, cefaclor, flomoxef, cefpodoxime,
aztreonam, imipenem, meropenem, gentamicin, amikacin,minocycline, fosfomycin, levofloxacin, and sulfamethoxazoletrimethoprim.
The isolates were examined by PFGE (Nippon Bio-Rad,Tokyo, Japan) analysis using the restriction enzyme XbaI.
The PFGE patterns of 10 of the 20 strains are shown in Fig.
1. The lack and/or addition of a band were seen in thedomain of 242.5 to 388 kb of the two strains (lanes 9 and 10),
while the remaining 18 strains showed the same pattern.
In conclusion, we considered that this case of food poisoning was caused by a single strain, EPEC O115:H19. However,
we could not determine the causative food and meal for thecase, since no isolates were detected either from the stool
samples of the food preparers nor from the food itself.
We are thankful to the staff of the health and welfarecenters for their provision of the interview data.
This article appeared in the Infectious Agents Surveillance
Report, vol. 25, no. 12, p. 22-23, 2004 in Japanese.

Fig. 1. PFGE patterns of E. coli O115:H19 digest with XbaI.
Lanes 1 to 10 : respective E. coli isolated from 10 sick persons.
M: λ DNA ladder.

REFERENCES
enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC),
enterohemorrhagic E. coli (EHEC), or enteroaggregative E.
coli (EAggEC), but that they were likely to be EPEC.
Moreover, in the antibiotic susceptibility examination by themicro-dilution broth test using a dry-plate (Eiken ChemicalCo., Ltd., Tokyo, Japan), 20 isolates were sensitive toall 17 antibiotics, i.e., ampicillin, piperacillin, cefazolin,

1. Yatsuyanagi, J., Saito, S., Kinouhi, Y., Sato, H., Morita,
M. and Itoh, K.(1996): Characteristics of enterotoxigenic
Escherichia coli and E. coli harboring enteroaggregative
E. coli heat-stable enterotoxin (EAST-1) gene isolated
from a water-borne outbreak. J. Jpn. Assoc. Infect. Dis.,70, 215-223 (in Japanese).

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