Dysentery bacillus is a dangerous and very easily transmitted pathogen. This bacterium causes an infectious inflammation of the intestine - dysentery (shigellosis). Cases of this disease are quite often observed in the summer season. Often, patients mistake this pathology for food poisoning. What are the symptoms of dysentery? And how is the causative agent of this intestinal infection transmitted? We will consider these issues in the article.
General Description
What is a dysenteric bacillus? The definition and description of this microorganism can be found in many textbooks on infectious diseases. This bacterium is also known as Shigella. It belongs to the Enterobacteriaceae family and has a rod-shaped form. When stained by Gram, shigella discolor. Such bacteria are called gram-negative. They have a dense cell membrane and are resistant to antibodies.
Shigella is an immobile microorganism. Her body does not have flagella and cilia. This bacterium cannot exist as spores and capsules.
By the method of reproduction, the dysentery bacillus does not differ from most bacteria. New microorganisms are formed as a result of division. Shigella reproduction occurs mainly in the human intestine. However, some varieties of these bacteria can divide in food.
According to the method of nutrition, the dysentery bacillus is a parasite. The bacterium exists at the expense of the human body. Shigella feed on organic matter produced in the intestines.
Classification
In microbiology, the following types of Shigella are distinguished:
- Flexner.
- Zonne.
- Grigorieva-Shiga.
- Boyd.
All of the above microorganisms are pathogenic and can cause dysentery. They differ only in some properties and types of antigens.
On the territory of Russia, cases of Flexner's and Sonne's dysentery are most often noted. The most severe form of pathology is caused by shigella Grigorieva-Shiga. But this type of infection has not been registered in our country in recent years; this disease is common in African countries. Boyd's dysentery is most common in South Asian countries.
Properties
Let's take a closer look at the properties of the dysentery bacillus. Shigella cannot form spores and is therefore quite unstable to environmental influences. However, the bacterium is able to survive under the following conditions:
- In moist soil - up to 60 days (at a temperature of +5 - +15 degrees).
- In milk, on berries and vegetables - up to 14 days.
- In wastewater - 1 month.
- On clothes, furniture and dishes - about 2 weeks.
At what temperature does a dysentery bacillus die? At +60 °C. bacteria are destroyed after 10 minutes. The boiling point of water (+100 degrees) kills shigella instantly. This microorganism also does not tolerate freezing. Its survival in cold conditions depends on the humidity of the environment.
When exposed to the rays of the sun, the causative agent of dysentery dies within 15-20 minutes. Disinfectants kill shigella within minutes.
Shigella are also destroyed under the influence of gastric juice, while they release toxins. However, this does not prevent infection, as the hydrochloric acid only kills a small portion of the bacteria.
Dysentery bacillus Sonne is one of the most resistant and hardy strains. This type of shigella is able to live in food: milk, meat, fish, salads and vinaigrettes. Bacteria can survive in foods from 3 to 120 days.
Transmission routes
The source of infection is a person suffering from acute or chronic dysentery. However, it is important to remember that it is possible to get infected from a recovering patient. After the disappearance of acute symptoms, the excretion of bacteria with feces continues from 7 to 30 days. In addition, people with strong immunity after infection can become asymptomatic carriers.shigella. Such patients do not feel any signs of the disease, but they can infect others.
Shigella get from the intestines of an infected person into the body of he althy people. This is the only way to get infected. Dysentery bacillus is transmitted in the following ways:
- Contact household. If an infected person does not observe personal hygiene after going to the toilet, then shigella spreads to various objects that the patient or bacteria carrier comes into contact with. If he althy people touch contaminated surfaces, then through unwashed hands they can bring the infection into their body. Quite often, small children who put their hands in their mouth become infected. The habit of biting nails also leads to infection.
- Water. Shigella get into water bodies along with infected feces. Most often this happens when there is insufficient wastewater treatment. He althy people can become infected by accidentally swallowing water while swimming in a pond. The contaminated liquid cannot be used even for watering plants.
- Food. Bacteria enter food through the contaminated hands of an infected person. Such cases are noted if the Shigella carrier is engaged in cooking or working in food production.
Domestic insects (flies, cockroaches) play a big role in the spread of shigella. They carry bacteria on their paws from contaminated objects to clean surfaces.
Most often there are cases of infection by contact-household. Any strain of the causative agent of dysentery can be transmitted in this way. often through waterShigella Flexner is spreading. This microorganism is able to survive for a long time in conditions of high humidity.
Shigella Sonne is most often transmitted by food. This is the most dangerous type of dysentery bacillus. According to the method of reproduction, this type of bacteria is somewhat different from other strains of Shigella. The causative agent of dysentery Sonne is able to live in products for a long time. This microorganism forms colonies not only in the human intestine, but also in food. Therefore, its numbers are rapidly increasing, and the risk of human infection through contaminated food is increasing.
Pathogenesis
For the development of the disease, it is enough to get 100 microbial bodies into the body. Bacteria secrete the following types of toxic substances:
- Endotoxins. They are released only when shigella are destroyed. Cause general intoxication of the body.
- Enterotoxins. Irritate the intestinal walls and stimulate the formation of fluid and s alts.
- Cytotoxins. Destroy intestinal epithelial cells.
- Neurotoxins. This type of poison is produced only by Grigoriev-Shiga bacteria. Toxins affect the central nervous system.
Pathology develops in several stages:
- Bacteria enter the body through the mouth. Then they enter the stomach, where part of the Shigella dies under the influence of hydrochloric acid. The destruction of bacteria is accompanied by the active release of endotoxins.
- Surviving dysenteric bacilli enter the intestines and release enterotoxins. Poisons act on the walls of the organ and increase the secretion of fluid and electrolytes.
- Bacteria produce cytotoxins and invade epithelial cells. This process is accompanied by the fight of immune cells against the infectious agent. At the same time, part of the Shigella dies and releases endotoxins.
- The inflammatory process begins in the walls of the intestine.
Shigella mainly affects the area of the sigmoid and rectum. Bacterial toxins affect not only the lower gastrointestinal tract, but also the heart, blood vessels and adrenal glands. If infection with Grigoriev-Shiga bacteria occurs, then the CNS is affected by neurotoxins.
If the treatment was carried out in a timely manner, the disease ends in recovery. As already mentioned, even after the disappearance of the symptoms of the pathology, the patient continues to secrete bacteria for some time. In some cases, dysentery becomes chronic.
Currently, thanks to the use of modern antibiotics, mortality from shigellosis has decreased to 5-7%. After a disease, a person does not develop stable immunity, so re-infection is possible.
Varieties of dysentery
The first signs of deterioration in he alth appear 1-7 days after ingestion of a dysentery bacillus. Symptoms of the infectious-inflammatory process largely depend on the form of pathology. Doctors distinguish the following types of dysentery:
- colitis;
- gastroenterocolitic;
- toxic;
- atypical.
Next, we will take a closer look at the symptoms of different forms of shigellosis.
Colitic form
In this type of disease, only the area of the large intestine is affected. The causative agent of the colitis form of dysentery most often becomes Flexner's shigella, less often - Grigoriev-Shiga's stick. There are three types of pathology, depending on the severity of symptoms:
- Easy shape. After the incubation period, the patient develops a fever up to +38 degrees. The patient feels weakness, chills, headache. This is accompanied by a decrease in blood pressure and a rare pulse. Then there are signs of an inflammatory process: abdominal pain, false urge to empty the intestines (tenesmus), frequent and loose stools (up to 10 times a day) with a mucosal-bloody admixture.
- Moderate form. The period of intoxication lasts about 4 days. It is accompanied by a strong fever (up to +39 degrees), a weakening of cardiac activity, a sharp drop in blood pressure. Then there are pains in the abdomen, which are cramping in nature. Severe diarrhea appears, the frequency of stools reaches 20 times a day, which leads to dehydration. Feces contain blood and mucus. With an instrumental examination of the colon, ulcers can be seen on the wall of the organ. The recovery period of the mucosa after recovery can take up to 1 month.
- Heavy form. The disease begins with a sudden rise in temperature to +40 degrees, a sharp deterioration in the general condition and chills. The patient has severe respiratory and cardiac disorders. Excruciating tenesmus and unbearable pains in the abdomen appear. Stool frequency - more than 20 times a day. Feces look like meat slops. There is paralysis of the anal sphincter, the opening of the rectum gapes. Full recovery of the gastrointestinal mucosa is possible only after 1.5-2 months.
The most severe and dangerous forms of colitis dysentery are caused by Grigoriev-Shiga shigella, the lighter ones by Flexner's sticks.
Gastroenterocolitic form
This type of dysentery is caused by Shigella Sonne. Pathology occurs with damage to the small and large intestines, as well as the stomach. With this form of shigellosis, the patient simultaneously develops general intoxication and inflammation of the digestive tract. The disease is accompanied by the following symptoms:
- fever (up to +39 degrees);
- pain in the upper abdomen;
- vomit;
- rumble in the stomach;
- tenesmus;
- diarrhea;
- admixture of mucus and undigested food in the feces.
The clinical picture of the pathology resembles signs of food poisoning. Also, with Sonne's dysentery, inflammation of the caecum often occurs. This is accompanied by pain in the abdomen on the right side. Often patients mistake such symptoms for manifestations of appendicitis.
This form of the disease is dangerous because the patient can quickly develop dehydration. Due to the loss of fluid, the patient's facial features are sharpened, there is a feeling of dryness in the mouth, and the heartbeat quickens.
The severity of gastroenterocolitic dysentery depends on the degree of dehydration. The more the patient losesliquids during diarrhea and vomiting, the worse he feels.
Toxic form
Toxic shigellosis is caused by the bacteria Grigoriev-Shiga. This is the most dangerous type of dysentery bacillus. The symptoms of the disease are very pronounced. Manifestations of extremely severe intoxication predominate:
- high fever (up to +40 degrees);
- awesome chills;
- confusion;
- convulsions.
Then comes bloody diarrhea with a frequency of stools up to 50 times a day and painful tenesmus. It is not uncommon for patients to die from cardiac depression before signs of bowel disease appear.
Atypical dysentery
Atypical form of the disease most often develops when infected with Boyd's dysentery bacillus, but can be caused by other strains of Shigella. This kind of dysentery is very mild. Severe diarrhea and tenesmus may be completely absent. There is only slight discomfort in the abdomen, and the stool becomes somewhat rapid and watery.
Often, this type of pathology is detected by chance during a medical examination. When probing the abdominal cavity, the patient experiences a slight soreness, and sigmoidoscopy reveals inflammation of the intestinal walls. The mucous admixture in the feces is almost invisible and is determined only by laboratory analysis.
Chronic dysentery
If the signs of dysentery do not disappear within 3 months, then doctors diagnose the chronic form of the disease. It develops with insufficient or belatedtreatment. There are two options for the course of the disease:
- Recurrent. Symptoms of dysentery subside for a while, but then the disease worsens again. Relapses of pathology proceed with erased symptoms. The chair becomes more frequent up to 5 times a day. There is no fever, abdominal pain, or tenesmus.
- Permanent. In this case, the pathological process is steadily progressing. The patient has persistent diarrhea with mucus and blood, a feeling of heaviness in the abdomen, and belching. The trophism and intestinal microflora are disturbed.
Features of pathology in children
Infection with a dysentery bacillus in a child often occurs against the background of other intestinal infections. In the analysis of feces, not only shigella, but also other pathogenic microorganisms can be detected. This complicates the course of the disease. In young children, dysentery often becomes chronic.
Shigellosis in childhood is accompanied by severe general intoxication and dehydration. There is severe diarrhea and vomiting. Feces become green and contain a lot of mucus. After recovery, normal bowel function is restored very slowly.
Diagnosis
Shigellosis in its manifestations can resemble other types of intestinal infections, and in some cases - food intoxication or appendicitis. Therefore, it is very important to conduct an accurate differential diagnosis. The following examination methods help to confirm or refute Shigella infection:
- Stool analysis for bacteria. This study consists in sowing biomaterial on specialnutrient media. If Shigella multiplication is noted, then the diagnosis is considered confirmed. At the same time, a test is carried out for the sensitivity of the bacterial strain to antibiotics. This helps to choose the most suitable drug for treatment. Culture analysis reveals shigella in 80% of cases.
- Blood test for antibodies to Shigella. This method is considered the most accurate. It detects the presence of bacteria in 100% of cases. For analysis, a preparation is prepared with erythrocytes, on which Shigella antigens are attached. The patient's blood is added to it. If at the same time an agglutination (gluing) reaction occurs, then this indicates the presence in the plasma of antibodies to the causative agent of dysentery.
Additional diagnostics are also prescribed:
- Clinical blood test. An increase in ESR and the number of leukocytes indicates an inflammatory process in the body.
- Sigmoidoscopy. This is an examination of the sigmoid and rectum using an endoscopic device. With dysentery, hyperemia of the mucous membrane and erosion on the walls of the intestine are revealed.
- Stool analysis for microscopy. With shigellosis, feces contain epithelial cells, neutrophils, as well as mucus and blood.
The above additional examination methods only indirectly indicate the presence of dysentery. The main diagnostic methods are culture tests and the presence of antibodies.
Treatment methods
What to do if a person is infected with a dysentery bacillus? It is not always possible to treat shigellosis at home. Atmoderate and severe forms of the disease require hospitalization in the infectious diseases department of the hospital. Outpatient therapy is possible only with mild dysentery. The patient is required to observe strict bed rest.
The treatment of shigellosis should be comprehensive. Therapy is carried out in the following areas:
- Antibacterial treatment. Prescribe antibiotics that act directly on the causative agent of shigellosis. These include nitrofurans (Furazolidone), fluoroquinolones (Ciprofloxacin, Ofloxacin) and quinol derivatives (Intetrix, Chlorquinaldol).
- Treatment with bacteriophages. They use special types of viruses that destroy the causative agent of the disease. In shigellosis, a specific dysenteric bacteriophage is used. It is prescribed in oral form, and also injected into the rectum with an enema. The bacteriophage is absolutely safe for the body, it only affects shigella.
- Symptomatic therapy. With severe diarrhea and vomiting, droppers are placed with Ringer's solution, and for oral administration, the drug Regidron is prescribed. This allows you to reduce intoxication and normalize the water-electrolyte balance. Also shown are enterosorbents ("Activated charcoal", "Enterosgel"), these drugs bind and remove Shigella toxins from the body.
It is important to remember that with dysentery you can not take medicines for diarrhea ("Loperamide", "Imodium"). Such drugsinterfere with the removal of bacteria from the intestines and slow down the healing process.
After a course of complex therapy, the patient needs to take probiotics ("Colibacterin", "Bifidumbacterin"). This will help restore the disturbed intestinal microflora and force out pathogenic bacteria.
Diet
With dysentery, you must follow a special sparing diet. Violation of the rules of nutrition can lead to a deterioration in the condition. The following products must be completely excluded from the daily menu:
- spicy food;
- fatty meals;
- fresh vegetables and fruits;
- smoked meats;
- sausages;
- canned food;
- rich meat broths;
- milk and dairy products;
- millet and pearl barley dishes;
- pasta;
- sweets;
- muffin;
- carbonated drinks;
- any kind of alcohol.
It is allowed to eat boiled dietary meat (chicken, veal, turkey), rice porridge, buckwheat and semolina, crackers and low-fat cottage cheese. The first dishes are prepared only on vegetable broth. It is recommended to drink green tea, rosehip broth, fruit or berry jelly. All food must be thoroughly cooked. It is necessary to consume at least 2 liters of fluid per day, as during illness the body loses a lot of water.
Prevention
To avoid infection with Shigella, the following recommendations of infectious disease doctors must be followed:
- Wash your hands regularly and respect personalhygiene.
- Cook meat and fish thoroughly.
- Rinse vegetables, fruits and berries well.
- Use only boiled water.
- While swimming in confined waters, avoid accidentally swallowing water.
- Do not use water from ponds for watering garden crops.
- Be very careful when dealing with people with dysentery.
- Destroy unwanted indoor insects.
Currently, the Shigellvac vaccine has been developed. It prevents infection with Sonne shigella. A vaccine for Flexner's dysentery is under development. In some cases, a dysenteric bacteriophage is used for emergency prevention of infection.
However, dysentery does not leave permanent immunity. Therefore, the vaccine is only valid for 12 months. Vaccination is not carried out en masse, but only according to strict indications. It is made for catering workers, medical staff of infectious diseases hospitals and bacteriological laboratories, as well as travelers traveling to regions disadvantaged by dysentery.
