39.1: Bacterial Food Poisoning

• Infectious Type: This type of food poisoning results from the ingestion of viable microorganisms that multiply in the GIT producing a true infection, for example, Salmonella and Shigella group of organisms, etc.

• Toxic Type: This type of food poisoning results from poisonous substances produced by multiplying organisms that have gained access to the prepared food, for example, enterotoxin produced by the Staphylococcus.

• Botulism Type: This type of food poisoning results from the ingestion of preformed Botulinum toxin in the preserved food. The toxin is produced by Clostridium botulinum.

39.2: Infectious Type

• In this type of food poisoning, the organisms multiply in the gut and cause gastroenteritis.

• The common organisms responsible for the attack are the Salmonella group of organisms.

• The natural reservoir of Salmonella organisms is in certain birds, mammals, and reptiles.

• Food may be contaminated with infected excreta of mice or rats, or infection may be transferred by flies or by human carriers employed in the handling of food.

• Shigella infection is the result of contamination of food or water supplies with the feces of individuals who either have the disease or, less often, are asymptomatic carriers of the organism.

• The types of foods that are particularly likely to be injected are twice-cooked meat dishes, fish dishes, soups, custards, milk, cream, ice cream, and tinned foods which, though initially sterile, may become infected if not immediately consumed after the tin has been opened.

• The outlook of Salmonella food poisoning is likely to occur whenever large amounts of food are prepared and unconsumed food is kept for future meals.

Signs and Symptoms

• The condition is not merely a toxemia but also gastroenteritis resulting from bacterial infection.

• The incubation period is longer than the staphylococcal food poisoning.

• The organisms multiply in the intestine and a delay of 12 hours or more is usual before symptoms occur.

• The onset is sudden and sometimes a chill may be the initial symptom, followed by headache, nausea and vomiting, severe abdominal cramps, and marked prostration.

• Three characteristics that help to differentiate this from poisoning with staphylococcal enterotoxin are:

  • Muscular weakness,

  • Fever, and

  • Very foul-smelling persistent diarrhea.

Treatment

• The stomach should be washed by gastric lavage and the bowel emptied by a cathartic if diarrhea is not present.

• Most patients recover rapidly with bed rest and warmth. No food is allowed until the acute symptoms are over.

• The rest of the treatment is symptomatic.

• The antibiotic of choice is chloramphenicol, up to 2 gm daily for an adult, for not more than 7 days.

Postmortem Changes

• These are those of gastroenteritis and general toxemia.

• The mucosa of the stomach and small intestine show varying degrees of inflammation and even ulceration. In severe cases, the lesions may extend to the large intestine. The liver, spleen, kidneys, and lungs are congested.

39.3: Mushrooms

• Mushrooms are fungi with umbrella-shaped tops and stems.

  • Stropheria semeglobata, Hypholoma fascicular, and Lactarius vellereus are among the poisonous varieties of mushrooms.

• Certain mushrooms act by parasympathomimetic action or may be due to hypersensitivity.

Signs and Symptoms

• Nausea, vomiting, diarrhea, bloody vomitus and stools, enlarged tender liver and jaundice, oliguria, pulmonary edema, mental confusion, convulsions, coma.

• Fatal Dose: ½ to 1 mushroom.

• Fatal period: 3 to 6 days.

Treatment

• Gastric lavage, supportive treatment, atropine, exchange transfusion in children, charcoal, and hemoperfusion in adults.