There are many different bacterial infections in the world. All of them differ from each other by the mechanisms of infection, the course of the disease and other nuances. In this article I want to talk in detail about clostridium botulinum - the causative agent of such a disease as botulism.
About the disease
At the very beginning, you need to say a few words about the disease itself that this bacterium causes. So, botulism is the hardest food intoxication. It is acute, often the central nervous system is affected, and paralysis can occur. Has a fecal-oral mode of transmission.
The origin of the name will be interesting. From the Latin language, botulism is translated as sausage (botulus). And all because the first time these pathogenic bacteria were found in this particular food product (as well as in the bodies of deceased people who previously ate infected sausage). Most often, this disease is associated with the consumption of salted and smoked fish, as well as ham.
A bit of history
For the first time, clostridium botulinum, the causative agent of botulism, was described back in 1896 by the scientist E. van Ermengem. This happened just at the time of the strongest outbreak of the disease. As already mentioned, this pathogenic microorganism was isolated from ham, as well as from the bodies of people who previously ate it. A little later it was found that the microorganism includes 8 serovars, which differ in the antigenic structure of toxins (they also form them). The toxins named as A, B and E are of the greatest importance. However, it is worth saying that all toxins can be neutralized exclusively by homologous serum.
Appearance
What does clostridium botulinum look like? So, the bacterium is a fairly large stick, the end of which is slightly rounded. Its approximate size is 4-9x0.6-1.0 microns. Throughout the body, it has approximately 35 flagella, peritrichously located. May form a spore. A stick with a spore is somewhat reminiscent of a tennis racket.
Ideal conditions
What are the ideal conditions for clostridium botulinum? So, the optimum temperature for their growth is about 35 ° C. However, the bacterium can also multiply in the temperature range from 10 to 55 ° C. The microorganism is best grown:
- In the midst of Kitta-Tarozzi. This is a special meat and peptone broth with the addition of liver, minced meat and glucose.
- On meat and fish extracts.
- Where there is a high concentration of animal protein.
Bacteria can also multiply in various environments. So, the most convenient is glucose-blood agar (in this case, the bacteria resemble pieces of lentils or cotton wool). However, they can multiply in a liquid medium. In this case, a uniform turbidity is formed, and after a while a specific precipitate falls to the bottom of the tube.
Spread
Where are the bacteria clostridium botulinum common? So, you can "stumble" on them almost anywhere. Most often, the following places are chosen for the habitat of clostridia:
- The intestines of fish, animals, and even mollusks.
- Soil (microorganisms get there along with feces).
- Food products. Particularly dangerous in this case for humans are vegetable, mushroom, meat and fish dishes.
Spores survive better in soil than vegetative forms of bacteria. Spores can withstand prolonged drying, freezing up to -250 ° C, boiling from one to six hours. And even in a phenol solution (5%), the spores of the bacteria can remain viable for up to 1 day. When boiled, the toxin is destroyed within about 10 minutes.
Sustainability
How persistent is botulism? Microbiology suggests that the microorganism itself behaves differently, being in different states.
- Spore form. In this case, clostridia is very resistant to various external changes. At a temperature of 6 ° C they can live for about a month, when boiled at 100 ° C they die only within an hour, at a temperature of 120 ° C - within half an hour. Spores are resistant to freezing, exposure to rays, and drying. As for disinfecting solutions, a formalin solution (20%) can kill the bacteria in two days, ethyl alcohol in two months, and a solution of hydrochloric acid (10%) in an hour.
- Vegetative form. In this state, clostridia is very vulnerable. At a temperature of 80 ° C they can die within an hour.
- As for the toxin, it behaves in the same way as the vegetative form. At 100 ° C for 10 minutes, the toxin can be neutralized. It is stable in an acidic environment, but can be neutralized in an alkaline environment . In the gastrointestinal tract, the toxin markedly reduces its activity. However, the exception is the type of botulism E, which, on the contrary, becomes 10,000 times more active in the human gastrointestinal tract.
Where is botulism maximally distributed? Microbiology, medicine say that most often patients are found in those countries where people are used to eating canned meat or fish. Seasonality in this case does not matter. Also unimportant age, gender, skin color of a person. Anyone can become infected.
Pathogenesis
Botulism is a severe food intoxication that can develop after the consumption of food contaminated with clostridia or their toxins (the toxin is released when the microorganism enters the anaerobic environment and begins its active reproduction). The most important in the case of a disease such as botulism is precisely neurotoxin. It is important to say that it is he who is the strongest of all existing biological poisons today. According to scientists, it is 375 times more toxic and stronger than rattlesnake venom . If you get the poison in its purest form, only 1 mg will contain up to 100 million lethal doses for a white laboratory mouse. As for humans, death can occur after taking only 0.001 mg of neurotoxin.
About neurotoxin
As mentioned above, the bacteria clostridium botulinum secrete the strongest and most dangerous neurotoxin, which is a threat not only to health but also to human life. It is also worth mentioning that this toxin is heat-resistant. It enters the intestine in the form of prototoxin; it is converted into the most dangerous microorganism after its treatment with small intestine enzymes. It is resistant to digestive enzymes. A distinctive feature: it is rapidly absorbed into the blood, already in the uppermost sections of the gastrointestinal tract. It spreads with blood throughout the body, entering the neuromuscular synapses.
Stage of action of the toxin
It is also necessary to talk about the fact that the botulinum toxin has three stages of action:
- Reversible stage (if antitoxic serum is used). Neurotoxin binds to a specific receptor.
- The movement of the toxin into the aqueous part of the cell of the neuromuscular junction. Temperature is important for this stage. The stage itself is difficult to reverse.
- The lytic stage. In this case, the toxin blocks the conduction of a nerve toxin into the muscle. This is where the main symptoms of botulism appear.
Types of Botulism
In medical practice, there are four main types of botulism:
- Food, or classic. Infection occurs by consuming food that contains a toxin.
- Wound. This type of disease is associated with contamination of the wound surface of a person.
- Botulism of the newborn. This is a pathological infection of the intestines of a newborn baby with bacteria.
- Uncertain classification. In this case, doctors can’t say exactly what caused the infection with human botulism.
About infection
How does botulism develop in a person? How does infection happen? First of all, it should be noted that it is impossible to get clostridia from a person. However, this microorganism enters the human body due to food that is contaminated with contaminated soil or feces. Further, for the onset of the disease itself, bacteria also need special conditions. So, if they are going to process food before meals, the microorganism instantly turns into a spore form, which is very resistant to the highest temperatures. After cooking, the spores begin to go into a vegetative state, when a deadly toxin is released by clostridia. It is worth noting that the microorganism is afraid of open oxygen. Reheating food is also not able to kill a pathogenic bacterium (for its destruction, a temperature of about 750 ° C is needed). Then, contaminated food enters the human body, and the disease manifests itself quite quickly.
Incubation period
Botulinum toxin after ingestion begins to act immediately. This happens in the first 8-22 hours after consumption of contaminated food. However, the average time is 10-12 hours.
The clinical picture of the disease
What happens to the human body after infection with this bacterium? So, at the very beginning, the symptoms will be similar to gastroenteritis (the inflammatory process of the mucous membranes of the small intestine and stomach). The main symptoms that cause botulism bacteria:
- Abdominal pain, mainly in the navel. The pain will increase, spread.
- The temperature most often does not rise.
- The chair is up to 20 times a day. It can be watery, plentiful, in the form of a rice broth.
- General weakness of the body.
- Vomiting
Vomiting and frequent stools can lead to general dehydration. In this case, convulsions may appear, the effect of wrinkles on the face, other skin integuments occurs. Most often, all symptoms disappear after a couple of days. And a person thinks that he has had ordinary intestinal flu. But it also happens that not everything is so good and quickly ends. In some cases, a person may have stools and vomiting with blood in it, and there may be very severe pain. Everything can even be fatal due to intestinal necrosis.
About flashes
Where is it most often possible to get a disease like botulism? Photos of foci of infection are multiple, but most often these are catering establishments, especially if a person consumes proteins of animal origin.
Prevention
What precautions can prevent a person from becoming infected with this bacterium?
- Boil botulism can kill. So, before eating any canned food, it is best to boil it for about 15 minutes. This will allow the toxin to break down. Also, you can not eat canned food, the lids of which are swollen.
- The bacterium that causes botulism dies at low temperatures. If possible, it is better to freeze meat and fish food products before cooking. It is also best to store them at temperatures below + 10 ° C.
- Especially carefully you need to process mushrooms. Since it is on them that particles of soil infected with clostridia can remain.
- People who ate the same food as those with botulism should be under the supervision of doctors. They also need to introduce amniotic anti-botulinum serum and enterosorbents as prophylaxis.
Forecast
What could end up with a disease like botulism? Photos of former patients are different. These are both people who have completely got rid of the disease, and the bodies of the dead. The latter scenario is possible only if the patient is not provided with timely and proper care. Without treatment, botulism takes a person’s life in 30-60% of cases.