Clostridium botulinum

Overview of a Pathogen: Clostridium botulinum According to The Bad Bug Book of the U.S. Food and Drug Administration (FDA) the common bacterium Clostridium botulinum is an “anaerobic, Gram-positive, spore-forming rod that produces a potent neurotoxin (108). Most individuals are probably best familiar with the spore as botulism. Botulism is a foodborne illness that has grown mercifully less common with the rise of canning and appropriate food sanitization measures, although it is still present in many countries and it still claims lives.

The Bad Bug Book states that botulism’s early symptoms vary, depending on the particular case, but usually manifests within 18-36 hours (The Bad Bug Book, 108). Seven types of adult botulism are recognized; another form of botulism, known as infant botulism, is the result of colonization of the infant’s intestinal tract after ingestion (The Bad Bug Book, 108). Symptoms can develop as early as 4 hours after consuming tainted food and as late as 8 days (The Bad Bug Book, 108).

Symptoms can be severe, including “double or blurred vision, drooping eyelids, slurred speech, swallowing problems, dry mouth, muscle weakness, constipation, and swollen abdomen” (The Bad Bug Book, 108). Although the rise of canning in modern food consumption has resulted in containment of the disease and a relatively low number of deaths, if someone is infected, the risk of disease is extremely high.

The disease is fatal in an estimated 5-10% of all cases, even with treatment and only a few nanograms are needed to produce symptoms (The Bad Bug Book, 111). The mechanism upon ingestion is as follows: “Botulinum toxin causes flaccid paralysis by blocking motor nerve terminals at the neuromuscular junction” (The Bad Bug Book, 108). Paralysis spreads throughout the body, beginning with the higher extremities, and if left untreated, can cause paralysis of the chest muscles and asphyxiation (The Bad Bug Book, 108).

The mechanism of paralysis is why unlike many other foodborne illnesses, botulism produces symptoms of constipation rather than diarrhea. This is also why the common cosmetic treatment Botox makes contained use of the toxin, to paralyze facial muscles and reduce the appearance of wrinkles (The Bad Bug Book, 108). All people, regardless of age, can manifest botulism, so long as they eat tainted foods.

Foods very low in acid such as canned corn, green beans, tuna fish, and salted fish, are good examples of foods which can become easily contaminated as a result, and it is recommended that such low-acid foods be canned with a 5% salt concentration to inhibit growth (The Bad Bug Book, 111). Lunchmeat and pates as well as improperly canned food has also been associated with botulism (The Bad Bug Book, 111).

Boiling canned foods for at least ten minutes before eating them (either homemade or store-bought) acts as a protective mechanism (The Bad Bug Book, 111). The website Foodborne Illness suggests avoiding consuming bad-smelling food, even if commercially prepared, as a further protective mechanism. Presence in the feces or serum is the most common way in which botulism is detected in a patient; the test takes 48 hours and culturing takes 5-7 days (The Bad Bug Book, 112). No vaccine exists to treat botulism, and the only treatment which exists is the administration.