Bacillus cereus -- Maine (2024)

On September 22, 1985, the Maine Bureau of Health was notified ofa gastrointestinal illness among patrons of a Japanese restaurant.Because the customers were exhibiting symptoms of illness while stillon the restaurant premises, and because uncertainty existed as to theetiology of the problem, the local health department, in concurrencewith the restaurant owner, closed the restaurant at 7:30 p.m. thatsame day.

Eleven (31%) of the approximately 36 patrons reportedly served onthe evening of September 22 were contacted in an effort to determinethe etiology of the outbreak. Those 11 comprised the last threedining parties served on September 22. Despite extensive publicity,no additional cases were reported.

A case was defined as anyone who had vomiting or diarrhea within 6hours of dining at the restaurant. All 11 individuals wereinterviewed for symptoms, time of onset of illness, illness duration,and foods ingested. All 11 reported nausea and vomiting; ninereported diarrhea; one reported headache; and one reported abdominalcramps. Onset of illness ranged from 30 minutes to 5 hours (mean 1hour, 23 minutes) after eating at the restaurant. Duration of illnessranged from 5 hours to several days, except for two individuals stillsymptomatic with diarrhea 2 weeks after dining at the restaurant. Tenpersons sought medical treatment at local emergency rooms on September22; two ultimately required hospitalization for rehydration.

Analysis of the association of food consumption with illness wasnot instructive, since all persons consumed the same food items:chicken soup; fried shrimp; stir-fried rice; fried zucchini, onions,and bean sprouts; cucumber, cabbage, and lettuce salad; ginger saladdressing; hibachi chicken and steak; and tea. Five persons orderedhibachi scallops, and one person ordered hibachi swordfish. However,most individuals sampled each other's entrees.

One vomitus specimen and two stool specimens from three separateindividuals yielded an overgrowth of Bacillus cereus organisms. Thehibachi steak was also culture-positive for B. cereus, although anaccurate bacterial count could not be made because an inadequateamount of the steak remained for laboratory analysis. No growth of B.cereus was reported from the fried rice, mixed fried vegetables, orhibachi chicken.

According to the owner, all meat was delivered 2-3 times a weekfrom a local meat supplier and refrigerated until ordered byrestaurant patrons. Appropriate-sized portions for a dining groupwere taken from the kitchen to the dining area and diced or sliced,then sauteed at the table directly in front of restaurant patrons.The meat was seasoned with soy sauce, salt, and white pepper, opencontainers of which had been used for at least 2 months by therestaurant. The hibachi steak was served immediately after cooking.

The fried rice served with the meal was reportedly customarilymade from leftover boiled rice. It could not be established whetherthe boiled rice had been stored refrigerated or at room temperature.Reported by J Vandeloski, Portland City Health Dept, KF Gensheimer,MD, State Epidemiologist, Maine Dept of Human Svcs; Enteric DiseasesBr, Div of Bacterial Diseases, Center for Infectious Diseases, CDC.

Editorial Note

Editorial Note: B. cereus is an aerobic, spore-forming,gram-positive rod with a ubiquitous distribution in the environment.Spores of B. cereus have been found in a wide variety of cereals,pulses, vegetables, spices, and pasteurized fresh and powdered milk.Food-poisoning can result from toxins elaborated by germinatingorganisms, which most commonly follows from inadequate refrigerationand subsequent reheating of foods that have already been cooked.

Two different clinical syndromes appear to be associated with B.cereus food poisoning, which correspond to two different toxinselaborated by the bacteria. A diarrheal syndrome similar toClostridium perfringens food poisoning with an average incubationperiod of 10-12 hours has been associated with a heat-labile toxinelaborated by B. cereus. An emetic syndrome similar to staphylococcalfood poisoning, with an average incubation period of 1-6 hours, hasbeen associated with a heat-stable toxin from B. cereus (1).

The emetic syndrome has almost always been associated with friedrice served in Oriental restaurants. The common practice of storingboiled rice at room temperature for subsequent preparation of friedrice has generally been implicated in such outbreaks. However, arecent, well-documented outbreak of the emetic syndrome of B. cereusin a British prison implicated beef stew (2). This was thought to becaused by adding to the stew vegetables that were cooked a day earlier.

Fresh meat cooked rapidly, then eaten immediately, seems anunlikely vehicle for B. cereus food poisoning. The laboratory findingof B. cereus in a foodstuff without quantitative cultures and withoutaccompanying epidemiologic data is insufficient to establish its rolein the outbreak. A negative culture of fried rice eaten with the mealdoes not exclude the obvious vehicle; reheating during preparation mayeliminate the bacteria in the food without decreasing the activity ofthe heat-stable toxin. While the question of the specific vehicleremains incompletely resolved, the clinical and laboratory findingssubstantially support B. cereus as the cause of the outbreak.

Most episodes of food poisoning undoubtedly go unreported, and inmost of those reported, the specific pathogens are never identified.Alert recognition of the clinical syndrome and appropriate laboratorywork permitted identification of the role of B. cereus in thisoutbreak.

References

1. Terranova W, Blake PA. Bacillus cereus food poisoning. N Engl J Med 1978;298:143-4.

2. CDC. Communicable disease report, no. 21, May 25, 1984:3.

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