By Frangiska Mylona,
-Dedicated to my mother, the woman and doctor I aspire to be.
Spores exhibit some peculiar characteristics by not having any metabolic activity, also, they do not divide nor do they replicate, they are dehydrated and they possess a small number of ribosomes. When the environmental conditions tend to become more favorable, spores turn into their vegetative forms.
The genus Clostridium has high heterogeneity and its different species can cause many serious and deadly diseases including tetanus, botulism, gas gangrene, and pseudomembranous colitis. In this article, botulism will be analyzed further. Clostridium botulinum has a worldwide distribution and is found in soil and occasionally in animal feces. Its main “weapon” against the human organism is its toxin named as Botulinum toxin produced during its growth and autolysis. This toxin can be adsorbed from the gut, enter blood circulation, and inhibit the release of one of the most important body’s neurotransmitters, acetylcholine at the site of synapses and neuromuscular junctions leading to flaccid paralysis and lack of muscle contraction.
Interestingly, the toxin cannot pass through the blood-brain barrier therefore it does not affect the central nervous system (CNS). The lethal dose for humans is approximately 1-2μg/kg but the toxin can be destroyed if heated for about twenty minutes at 100 degrees Celsius. This extremely potent bacteria occurs naturally in foodborne botulism, infant botulism, and wound botulism. The first one is caused by the ingestion of the toxin produced from Clostridium botulinum after thriving to survive in the anaerobic environments provided by canned foods especially when they are made amateurishly at home, as well as from smoked, spiced, or vacuum-packed foods. Also, commercial foods have shown a huge incline in outbreaks of botulism including repeated episodes of botulism by ingestion of sauteed onions in restaurants.
Infant botulism is related to infants younger than one year of age ingesting the spores of these bacteria which are commonly found in honey. The main difference between infants and adults with botulism is that in infants the ingested spores will germinate within their gastrointestinal tract, turning into their vegetative state and producing the toxin inside their bodies which will get absorbed into their bloodstream. On the other hand, these bacteria are unable to colonize the adult’s gastrointestinal tract. In infants, the symptoms are classified under the term “floppy baby” including poor feeding, weakness, and flaccid paralysis that can lead to sudden death.
Wound botulism is rarer and it is associated with injectable drugs like contaminated “black tar” heroin. The wound will get contaminated with Clostridium botulinum spores and then, the toxin will be secreted at the site of the wound.
Generally, the symptoms will appear eighteen to twenty-four hours after the ingestion of the toxin causing visual disturbances like diplopia, loss of eye accommodation, ptosis, cranial nerve palsies with impaired extraocular muscles, and fixated dilated pupils. Other manifestations include the inability to shallow along with speech difficulties like dysphonia, dry mouth, and dysphagia. Often nausea and vomiting can be present but without fever. All of these can further lead to flaccid paralysis progressing to respiratory failure and cardiac arrest that can easily lead to death.
When diagnosing botulism, it more is important to detect the toxin than the organism itself. First of all the appropriate health authorities need to be contacted and then, the collected specimens will be transferred to the laboratories. The types of tested specimens can be serum, gastric secretions, or stools of the patient and they must be transported in anaerobic containers. Next, mice can be beneficial in proving the presence of the toxin by being injected intraperitoneally with the specimens whereas if botulism is the case, the injected mice will die. Other methods to detect the toxin include ELISA and PCR.
In terms of treatment, it should be intensive and supportive including mechanical ventilation, intubation along the use of potent antitoxins administered intravenously. Also, a skin test is recommended to exclude hypersensitivity against the antitoxin preparation. The antitoxin will not prevent the paralysis but its advancement. In infants, human-derived botulinum immune globulin (IBG) is recommended. In cases of wound botulism antibiotics like intravenous Penicillin or intravenous Metronidazole, can be administered. As the saying goes, prevention is better than cure. Thus, it is recommended that canned foods be boiled for twenty minutes before consumption to prevent infection with the spores of Clostridium botulinum. A great deal of care should be taken in preparing commercially canned foods and home-made canned foods such as beans, corn, peppers, peas, smoked fish, and vacuum-packed fresh fish.
It is peculiar that the Botulinum toxin has a “doubled-faced” action. Due to its potency and its ability to kill organisms, it is considered an agent that can be used for bioterrorism or biological warfare. In bioterrorism, the toxin would be used as aerosol or it could be put into food supplies leading to massive killing. On the other hand, this toxin is used for a famous medical procedure known as Botox, commonly known for its cosmetic reputation, however, it can also be advantaged for relieving muscle spasms and dystonias.
To conclude, it is important to pay particular attention when eating canned foods, as well as the diet of an infant should be closely monitored and discussed with a pediatrician. Even though such small bacteria can be responsible for such dangerous symptoms, if they are properly manipulated, they are capable of adding great value to patients’ lives not only cosmetically but also in terms of treating severe diseases. In any case, Clostridium botulinum should be taken seriously especially if someone has been suspected of suffering from it due to its high “killing capabilities,” which if left untreated, can unfortunately result in death.
References
- Jawetz, Melnick & Adelberg’s Medical Microbiology, Twenty-Eighth Edition.
- Theodore X.O’Connell, Ryan A.Pedigo, Thomas E.Blair, Crush Step 1, The Ultimate USMLE Step 1 Review, second edition
- Maxine A. Papadakis MD, Stephen J. McPhee MD, Michael W.Rabow MD, Kenneth R.McQuald MD. Associate editor Monica Gandhi MD, MPH,Current Medical Diagnosis & Treatment 2024, sixty-third edition
