Jpn. J. Infect. Dis., 59, 2006

Laboratory and Epidemiology Communications

An Outbreak of Water-Borne Gastroenteritis Caused byDiarrheagenic Escherichia coli Possessing eae GeneAi Baba*, Sumi Ebuchi, Kayo Uryu, Hiroshi Hiwaki, Kikuyo Ogata1,
Etsuko Washimi1, Akio Hasegawa1 and Shizuo Utiyama1
Fukuoka City Institute for Hygiene and the Environment, Fukuoka 810-0065, and1
Oita Prefectural Institute of Health and Environment, Oita, 870-1117, Japan
Communicated by Haruo Watanabe(Accepted November 17, 2005)
11 patients was OUT:H-, and O168:H- eae-positive E. coli
was also isolated from 1 of the 11 patients. The biochemical
properties of these isolates were common: motility –, TSI agar
R/Y, β-galactocidase +, and β-glucuronidase – (Table 1). TheE. coli strains which possessed only eae were also isolated
from the water samples, and their serotypes were OUT:HNT,
O119:HNT, and O168:H-. The biochemical properties of theO168:H- strains isolated from water samples were the sameas those of the patient isolate (Table 1).
The strains of E. coli OUT:H- and O168:H- isolated frompatients were examined by RAPD-PCR using RAPD primers
2, 3 and 4 (Amersham Biosciences Corp., Buckinghamshire,UK). All of the E. coli OUT:H- strains showed the same RAPD
patterns but differed from the E. coli O168:H- strain (datanot shown).
According to the epidemiological research of this outbreak,because the onset of symptoms of the patients varied greatly,
it was suspected that this outbreak was not a food-borne
infection but a water-borne infection. The E. coli OUT:Hand O168:H- isolated from the patients and the OUT:HNT,
O119:HNT, and O168:H- from the spring water possessed
only eae. The biochemical properties of the O168:H- strain
isolated from a patient was the same as that from the springwater samples. Therefore, it was concluded that this outbreak
was caused by enteropathogenic E. coli, and the infection
source was spring water of the campground.
The public health center found that residual chlorine was
not detected in the water supplied to the campground andtherefore concluded that water quality management was not

From July 19 to July 23, 2005, an outbreak of gastroenteritis occurred among the students and teaching staff at ahigh school in Fukuoka City, Japan. A total of 409 persons,including 393 students and 16 staff members, went camping
at a town in Oita Prefecture, from July 18 to 20. Among them,
174 students and 2 staff members showed symptoms such as
watery diarrhea, abdominal pain, vomiting and fever (36.5 39.5°C). The foods in the camp were either cooked by thecampers or catered. The self-prepared foods were curry andrice, salad and “miso soup with pork”; the catered foods werebread, “box lunches with rice balls,” and sandwiches. Thewater source of the campground was spring water, and water
saved in a tank was supplied to the faucets in the camping
facilities. The management company in the campgrounddisinfected the water once a day with hypochlorite and gave
users a verbal warning not to drink the water.
Stool samples collected from 20 patients were examined
at Fukuoka City Institute for Hygiene and the Environment,
and 5 water samples that were collected from the water source,
the diversion tank, the storage tank, the toilet and the bathroom were examined at Oita Prefectural Institute of Healthand Environment. Although Escherichia coli strains wereisolated from the stool and water samples, no other food poisoning bacteria were isolated. The strains of E. coli isolated
from 20 patients were examined by means of PCR to identify
the virulence genes (1). Although they were negative for VT,
LT, ST, invE, ipaH, bfpA and aggR, the strains isolated from
11 patients were positive for eae.
The serotype of eae-positive E. coli strains isolated from

Table 1. Properties of the isolated E. coli
Serotype

β-galactocidase(ONPG)

β-glucuronidase(X-GLUC)eae gene

TSI agarNo. of positive samples/
No. of samples examined
11/20
1/20

Patients

OUT:HO168:H-++––++R/Y
R/Y

Spring water(storage tank)

OUT:H NT*
O119:H NT*
O168:H-+++++–+++Y/Y
Y/Y
R/Y

Spring water(bathroom)

O168:H-+–+R/Y*NT, not tested.

*Corresponding author: Mailing address: Fukuoka City Institutefor Hygiene and the Environment, 2-1-34, Jigyohama, Chuoku, Fukuoka 810-0065, Japan. E-mail: micro@fch.chuo.fukuoka.
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proper. Although the campers knew that the water supplied
was not for drinking, they drank the water carelessly, because
there were no caution signs where the water was supplied. Itis thought that this outbreak was generated by three elements:
improper water quality management, insufficient caution signs
and a lapse of judgment on the part of the students and theteaching staff.

REFERENCE
1. Kobayashi, K., Seto, K., Yatsuyanagi, J., Saito, S., Terao,M., Kaneko, M., Serikawa, T., Kuramoto, S., Fujisawa,T., Suzuki, R., Yamazaki, M., Hayashi, K., Matsune, W.,Yasuoka, T., Horikawa, K., Murakami, K., Kawano,K., Yamada T. and Ito, K. (2002): Presence of the genes
regarding adherence factors of Escherichia coli isolates
and a consideration of the procedure for detection ofdiarrheagenic strain. J. Jpn. Assoc. Infect. Dis., 76, 911920 (in Japanese).

This article appeared in the Infectious Agents Surveillance
Report (IASR), vol. 26, p. 275-276, 2005 in Japanese.

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