There are many different bacterial infections in the world. All of them differ from each other in the mechanisms of infection, the course of the disease and other nuances. In this article, I would like to talk in detail about clostridium botulinum, the causative agent of such a disease as botulism.
About illness
At the very beginning, a few words should be said about the very disease that this bacterium causes. So, botulism is a severe food intoxication. It proceeds acutely, often with the central nervous system affected, paralysis may occur. Has fecal-oral transmission.
The origin of the name will be interesting. Botulism is translated from Latin as sausage (botulus). And all because for the first time these pathogenic bacteria were found in this particular food product (as well as in the bodies of dead people who had previously eaten contaminated sausage). Most often, this disease is associated with the consumption of s alted 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. It happened just at the time of the strongest outbreak of the disease. What alreadyit was said that this pathogen was isolated from ham, as well as from the bodies of people who had previously eaten 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 most important are the toxins named as A, B and E. However, it is worth saying that all toxins can only be neutralized by homologous serum.
Appearance
What does clostridium botulinum look like? So, the bacterium is a rather large stick, the end of which is slightly rounded. Its approximate size is 4-9x0.6-1.0 µm. Throughout the body, it has approximately 35 flagella, located peritrichously. May form spores. A stick with a spore is somewhat reminiscent of a tennis racket.
Ideal conditions
What are the ideal conditions for clostridium botulinum? Thus, 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. Best grown microorganism:
- In the Kitt-Tarozzi environment. This is a special meat-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 also reproduce in a liquid medium. In suchcase, a homogeneous turbidity is formed, and after a while a specific precipitate falls to the bottom of the test tube.
Distribution
Where is clostridium botulinum common? So, you can “stumble” on them almost anywhere. Most often, the following places are chosen for the habitation of clostridia:
- The intestines of fish, animals and even shellfish.
- Soil (microorganisms get there with feces).
- Food. 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 to -250°C, boiling from one to six hours. And even in a solution of phenol (5%), bacterial spores can remain viable for up to 1 day. Boiling destroys the toxin in about 10 minutes.
Sustainability
How persistent is botulism? Microbiology says that the microorganism itself behaves differently, being in different states.
- Spore form. In this case, clostridia are very resistant to various kinds of 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, drying. As for disinfectant solutions, a formalin solution (20%) can kill a bacterium in two days, ethyl alcohol - within two months, and a saline solutionacids (10%) - per hour.
- Vegetative form. Clostridia are very vulnerable in this state. At 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. Stable in an acidic environment, but can be neutralized in an alkaline environment. In the gastrointestinal tract, the toxin significantly reduces its activity. However, the exception is type E botulism, which, on the contrary, becomes 10,000 times more active in the human gastrointestinal tract.
Where does botulism spread the most? Microbiology, medicine say that most often patients are found in those countries where people are used to eating canned meat or fish. Seasonality does not matter in this case. Age, gender, skin color of a person are also unimportant. Anyone can get infected.
Pathogenesis
Botulism is a severe food intoxication that can develop after 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 when considering a disease such as botulism is precisely the neurotoxin. It is important to say that it is he who is the most powerful of all biological poisons that exist today. According to scientists, it is 375 times more toxic and stronger than rattlesnake venom. If the poison is obtained in its pure form, only 1 mg will contain up to 100 million lethal doses for a white laboratory mouse. As far as man is concerned,death can occur after taking as little as 0.001 mg of the neurotoxin.
About neurotoxin
As mentioned above, the bacteria clostridium botulinum secrete the strongest and most dangerous neurotoxin, which is a threat not only to he alth, but also to human life. It should also be said that this toxin is heat-resistant. It enters the intestines in the form of prototoxin, it turns into the most dangerous microorganism after it is processed by the enzymes of the small intestine. It is resistant to the effects of digestive enzymes. Distinctive feature: it is quickly absorbed into the blood, being already in the uppermost parts of the gastrointestinal tract. With the blood it spreads throughout the body, entering the neuromuscular synapses.
Stages of toxin action
It is also necessary to tell that the botulinum toxin has three stages of action:
- Reversible stage (in case of using antitoxic serum). The neurotoxin binds to a specific receptor.
- Movement of the toxin to the aqueous part of the neuromuscular junction cell. Temperature is important for this step. The stage itself is difficult to reverse.
- The lytic stage. In this case, the toxin blocks the passage of nerve toxin into the muscle. This is where the main symptoms of botulism occur.
Types of botulism
In medical practice, there are four main types of botulism:
- Food, or classic. Infection occurs through the consumption of food that contains the toxin.
- Wound. This type of disease is associated with contamination of the wound surface of a person.
- Botulism in newborns. This is a pathological infection of the intestines of a newborn baby with bacteria.
- Undefined classification. In this case, doctors cannot say for sure what caused the human botulism infection.
About infection
How does botulism disease occur in humans? How does infection occur? First of all, it should be noted that it is impossible to get clostridium from a person. However, this microorganism enters the human body through food that is contaminated with contaminated soil or feces. Further, for the occurrence of the disease itself, bacteria also need special conditions. So, if food is going to be processed before eating, 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 the deadly toxin is released by Clostridium. It is worth noting that the microorganism is afraid of open oxygen. Reheating food is also not able to kill pathogenic bacteria (to destroy it, a temperature of about 750 ° C is needed). Then the contaminated food enters the human body, and the disease manifests itself rather quickly.
Incubation period
Botulinum toxin after entering the body 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.
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 (an inflammatory process of the mucous membranes of the small intestine and stomach). The main symptoms that cause botulism bacteria are:
- Pain in the abdomen, mainly in the navel. The pain will increase, spread.
- Temperature often does not rise.
- Stool happens up to 20 times a day. May be watery, copious, like rice water.
- 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 and other skin integuments occurs. Most often, all symptoms disappear after a couple of days. And the person thinks that he has suffered the usual intestinal flu. But it also happens that not everything ends so well and quickly. In some cases, a person may have stools and vomit with blood, and there may be very severe pain. Everything can even end in death due to the occurrence of intestinal necrosis.
About outbreaks
Where are you most likely to catch a disease like botulism? Photos of foci of infection are multiple, but most often these are public catering establishments, especially if a person consumes animal proteins.
Prevention
What precautions can protect a person from infection with this bacterium?
- Can kill botulism boiling. 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, do not eat canned food, the lids of which are swollen.
- The bacterium that causes botulism dies at low temperatures. If possible, meat and fish food should be frozen before cooking. It is also best to store them at temperatures below +10°C.
- Mushrooms should be handled with special care. Since it is on them that particles of soil infected with Clostridium can remain.
- People who ate the same food as those with botulism should be under the supervision of doctors. They also need to administer amniotic anti-botulinum serum and enterosorbents as a preventive measure.
Forecast
How can such a disease as botulism end? Photos of former patients are different. These are both people who completely got rid of the disease, and the bodies of the dead. The last scenario is possible only if the patient is not provided with timely proper assistance. Without treatment, botulism takes a person's life in 30-60% of cases.
