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Quick Reference Environment: ubiquitous,
soil-borne pathogen Identification C. botulinum is a Gram-positive, anaerobic spore-forming rod that produces one of the most potent toxins known. The spores are heat-resistant and can survive in inadequately heated, prepared, or processed foods. Sausages, seafood products, milk, and canned vegetables are the most frequent vehicles for human infection. Botulinal toxin has been found in a wide variety of foods, including canned corn, peppers, green beans, soups, beets, asparagus, mushrooms, ripe olives, spinach, tuna fish, chicken and chicken livers and liver pâté, and luncheon meats, ham, sausage, stuffed eggplant, lobster, and smoked and salted fish.[1] Almost any food that has a high pH (above 4.6) can support growth of C. botulinum. Honey is the most common vehicle for infant botulism. Pathogenesis C. botulinum produces a powerful neurotoxin that prevents the release of acetylcholine at the neuromuscular junction, thereby inhibiting muscle contraction and causing paralysis. The CDC classifies four forms of the disease: (1) food-borne; (2) infant; (3) wound; and (4) indeterminate. Food-borne botulism is perhaps of most concern to public safety. The toxin is heat labile and can be destroyed by heating to 10oC for ten minutes or longer. The pathogenesis of wound botulism, the rarest form of botulism infection, is very similar to that of tetanus, except a different toxin is produced. This type of infection occurs when C. botulinum, perhaps along with other organisms, infects an individual via an open wound and produces toxins that travel throughout the bloodstream. Undetermined cases of botulism involve adult patients where a specific cause for the infection cannot be determined. Only a few nanograms of the organism can cause illness. In food-borne botulism, the incubation period can be anywhere from 18 to 36 hours after ingestion of infected food. Manifestations The incidence of food poisoning caused by C. botulinum is low, but cause for concern due to high mortality rates. Early signs of infection include lethargy, weakness, and vertigo. Symptoms progress to abdominal pain, diarrhea, vomiting, blurred vision, dizziness, and motor difficulties. As the disease advances, paralysis gradually moves from the face, to the throat, chest, and extremities, eventually making breathing difficult. With the diaphragm and chest muscles involved, death from asphyxiation often occurs. Treatment Laboratory tests can detect the presence of toxin or a culture can be grown from a stool sample. Treatment for food-borne botulism includes administration of botulin antitoxin and intensive respiratory care. Death occurs in 70% of untreated cases. Prevention Anywhere from 20 to 50 outbreaks of botulism are reported annually in the United States. All people are susceptible to food-borne toxins, but food poisoning can be prevented by properly processing and preserving foods. Do not use canned foods that are bulging or have a foul odor. |
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