Jpn.J.Infect.Dis., 52, 1999

Laboratory and Epidemiology Communications

Outbreak of Salmonellosis Caused by Ingestion of Cuttlefish Chips: Epidemiological Analysis by Pulsed-Field Gel Electrophoresis

Kokichi Hamada*, Hidetaka Tsuji, Kuniyoshi Masuda and Kanjiro Uemura1

Division of Microbiology, Hyogo Prefectural Institute of Public Health, Arata-Cho 2-1-29, Hyogo-Ku, Kobe 652-0032, and 1Uemura Pediatric and Internal Medicine Clinic, Niijima 10-3, Shizuki, Tsuna, Hyogo 656-2132, Japan

Communicated by Shunsuke Imai

(Accepted May 11, 1999)

Between January and April 1999, sporadic outbreaks of Salmonella infections were reported at Awaji Island and Himeji City in the central part of Japan. These outbreaks affected children aged 1-12 years, who experienced watery, mucous and/or hemorrhagic diarrhea.

Seventeen Salmonella isolates from Awaji Island were all typed as a serovar Salmonella Oranienburg. Two fecal isolates sent from Himeji City to our institute were also identified asSalmonella Oranienburg (1). Epidemiological studies identified "Oyatsu-Chinmi" (a children's snack consisting of processed cuttlefish chips) as a primary source of food poisoning. Ten out of fifteen affected children on Awaji Island consumed the snack several days before becoming ill. "Oyatsu-Chinmi" was produced by company A in Tokyo, and the company purchased the cuttlefish material from company B in Aomori Prefecture in the northern part of Japan. Six different lots of the snack were obtained from retail stores on Awaji Island, and examined for contamination by Salmonella. Mannitol Selenite Medium (Oxoid Ltd., Hampshire, England) was used for the isolation. All the samples were contaminated by Salmonella of the identical serovar, Salmonella Oranienburg.

Nineteen isolates from children and six isolates from "Oyatsu-Chinmi" were examined by pulsed-field gel electrophoresis (PFGE) using a Gene Path Typing System (Nippon Bio-Rad, Tokyo). In all these isolates, PFGE of BlnI restriction enzyme-digested chromosomal DNAs gave an identical pattern (Fig. 1). PFGE of XbaI digests also gave the same pattern (data not shown). The results strongly suggested that the diffuse outbreak of the food poisoning in Awaji Island was caused by "Oyatsu-Chinmi" contaminated by the same Salmonella strain. After our first isolation of Salmonella Oranienburg, there were increasing numbers of reports of outbreaks caused by the cuttlefish foods in various parts of Japan. These foods were produced by different manufacturers, but all the raw cuttlefish materials were procured from company B. It remains a mystery how Salmonella contaminated the cuttlefish material and survived in these foodstuffs.

REFERENCE

  1. Hamada, K., Tsuji, H. and Masuda, K. (1999): An outbreak of Salmonella Oranienburg in the Hyogo Prefecture. Infect. Agents Surveillance Rep., 20, 87 (in Japanese).

*Corresponding author : Fax: +81-78-531-7080

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