Listeria monocytogenes is a gram-positive microscopic life form that causes listeriosis in humans. The bacterium multiplies in food. Once in the human body, it penetrates into the cellular structure, where it remains to parasitize. Studies have shown that predominantly pathogenic microflora is concentrated in the liver, spleen.
Relevance of the issue
If you look at the news bulletins, you can find quite a bit of reliable information about the infection of listeriosis. This is due to the difficulty of identifying pathogenic microflora - not every laboratory has the equipment to isolate listeria or antibodies generated by the body. The incidence rate is considered to be rather low, while the pathology itself is especially dangerous. In adults, the average death rate is up to 30%, in newborns, the risks reach 80%.
Most of all, Listeria monocytogenes is dangerous for those who are expecting a babywomen and the elderly. In the first case, infection can provoke pathological changes in the fetus, in the second case, infection often proceeds according to a severe scenario. It has been established that the risk of developing listeriosis is higher if the immune system is weak, the person has suffered or suffers from serious illnesses. As a rule, listeriosis only completes the chain of pathologies, usually becomes the final step of infection, followed by death.
Pathogens: where are they?
Listeria monocytogenes is a pathogenic microflora often found in the human environment. Bacteria can be detected by studying soil and water samples. Sometimes they are found in plants, feces, sewage. Listeria is considered comfortable over a wide temperature range, they can multiply intensively in the refrigerator and at even lower temperatures. Death occurs at boiling point. If food is processed under conditions of heating up to 65 ° C, pathogenic microflora will die after 35 minutes.
A distinctive feature of the distribution of Listeria monocytogenes in food products is the fact that the pathogenic microflora is not afraid of s alt treatment. Traditionally, people, wanting to get safe food, s alt vegetable, meat, dairy dishes, as it has been established that this helps to protect against many bacteria. S alt concentrations up to 20% in the environment are safe for Listeria.
Features
Food research has shown that Listeriamonocytogenes also survives in low oxygen conditions, so it can multiply in food packed in vacuum bags.
For pathogenic microflora, an acidic environment is categorically unfavorable. Listeria actively spreads when the pH is close to neutral.
In general, as experiments have shown, Listeria is characterized by the ability to easily and quickly adapt to environmental conditions, which provides bacteria with high survival in an aggressive environment.
Risks: where they are greatest
The widespread distribution and increased dangers have become the basis for the introduction of special standards. The products produced by them are minimally dangerous to humans. In our country, GOSTs are recognized as standards. Listeria monocytogenes can be found in dairy products, more often in milk and cheese, in meat foods, including processed foods and poultry, in vegetables (the greatest risks for tomatoes, celery and lettuce prepared from raw cabbage). Given this feature of distribution, production standards have been introduced to minimize the dangers to the consumer.
However, the listed varieties of food are nothing more than examples of increased risk. As doctors and scientists point out, listeria can theoretically be contained in any raw product.
How to detect?
It is possible to identify listeriosis infection in food by examining food samples in the laboratory. For this, a speci altesting. Bioluminescence technology is often used. The method was not developed to detect Listeria, but has proven to be one of the most reliable when it comes to assessing the risks of product contamination.
Any object that has not been disinfected and thoroughly cleaned should be considered as a potential source of Listeria.
Infection: how does it happen?
Since Listeria monocytogenes is more common in food products, accordingly, this route of infection can be considered one of the most typical. In addition, infection is possible if a person comes into contact with a living sick individual - a bird, an animal. You can get sick if there was contact with food contaminated with soil, feces, in which Listeria is especially common. If a person, by virtue of his profession, is constantly in contact with raw materials, milk, meat, live individuals, the likelihood of infection increases significantly. The risk group for listeriosis is primarily formed by workers in the agricultural sector, dairy, meat and other food industries.
As studies of listeriosis have shown, the alimentary route of penetration of the pathogen into the human body is the main one. True, this does not exclude the danger of implementation in other ways. Listeria can penetrate through the mucous membranes that line the respiratory organs - microflora enters here with air and dust. There is a danger of infection through eye tissues, wounds on the skin. The sick person and the carrier of the microflora actively spread listeria in the environment. The maximum risk is associated with a carrier state in which there are no symptoms, andmild, latent forms of diseases in which there are no clinical manifestations.
Can I warn you?
Prevention of listeriosis in people begins with the observance of technological procedures and rules in food production. It is necessary to strictly follow the established temperature regimes, process raw materials in the recommended sequence, using the equipment in the correct mode. To reduce the risk, it is necessary to monitor the correctness of transportation, compliance with packaging requirements, and take a responsible attitude to the warehousing and storage of raw materials and products. Minimization of risks is possible if the enterprise maintains a high hygienic, sanitary level.
Assessing the risks and danger of the spread of Listeria monocytogenes, it must be remembered that the penetrating ability of the pathological microflora is very high, the prevalence is also. It is practically impossible to guarantee the absolute absence of germs within the production site. Surely bacteria will live in areas that are difficult to access - equipment, some parts of work areas. From these areas, the infection can spread to others previously treated. A high-pressure washer provides exceptionally comfortable conditions for the growth of Listeria colonies, since the bacterium can move with condensed masses and aerosols.
And what to do?
Re-infestation with Listeria of an area previously treated with disinfectants is quite large, and in order to avoid it, it is necessaryregularly carry out preventive maintenance. To do this, use drugs that are effective against gram-positive microscopic flora. As established during testing, Listeria is dangerous with a variety of high-quality disinfectants.
As experts call, only regular treatment with disinfectants does not give a really reliable result. To minimize risks, hygiene standards must be strictly followed. Only authorized people should enter the workshop. Sanitary barriers help reduce the risk of contamination of the finished product. The best option is a hygiene plan.
How to notice?
Indicating the need for treatment, the symptoms of listeriosis usually appear after 1-28 days from the moment the pathogen enters the human body. The disease may appear in an anginal form. The patient has a fever, a headache, his appetite worsens. Checking the lymph nodes shows an overgrowth of this area. There is a possibility of an ocular glandular form. At the same time, the eyelids turn red, the eyes secrete substances containing pus. In the typhoid variety, rash zones form on the patient's body.
What to do?
When infected with Listeria monocytogenes, treatment is determined by the stage of development of the disease, at which it was possible to make an accurate diagnosis. The best prognosis is if the pathology has just begun to develop. As a rule, an antibacterial course is started. It is especially important to strictly follow the program chosen by the doctor if listeria has caused meningitis and other severe symptoms of infection. If the disease is found inpregnant, an adequate antimicrobial course can prevent infection of the fetus.
Symptoms of listeriosis are in many ways similar to other infectious diseases. To choose the optimal treatment program, to select effective medicines, the doctor first takes samples of organic tissues to determine the microflora. Without correct laboratory diagnosis, listeriosis cannot be established, which means that it will be extremely difficult to find the right treatment.
Special Occasion: Babies
Sometimes Listeria monocytogenes infects the body of a newborn. Infection is possible at the time of birth or after this event. In addition, the bacterium can enter the fetus through the placenta. The manifestations of the disease are similar to sepsis, and for the correct choice of treatment, it is first necessary to accurately assess the condition of the child (for this, he and the mother will have to be tested). Listeriosis is diagnosed if the tissue samples taken for culture from the patient who gave birth to him showed the presence of the pathogen. Therapy in this case begins with a combination of drugs containing ampicillin and aminoglycosides.
Infection during intrauterine development can cause granulomas in unpredictable areas, including the brain. If observation shows a rash, neonatal granulomatosis is diagnosed. Pulmonary infection is possible if strangulation has occurred, the child accidentally swallowed the mother's vaginal discharge, amniotic substance. The disease develops in the first few days after birth, proceeds very quickly. Typical manifestations -state of shock, distress syndrome.
State Clinic
It is not uncommon for pregnant women to become infected with Listeria without symptoms. There is a possibility of primary bacteremia. The disease is similar to the flu, has no specific symptoms, so listeria infestation cannot be suspected.
In a fetus, an infant, the clinical condition is determined by the way the pathological microflora enters the body, the duration of its stay inside. There is a possibility of premature induction of labor, the birth of a dead child, spontaneous abortion. If childbirth begins ahead of time, as a rule, amniotic fluid has a specific brownish tint. Matter is cloudy. There is a possibility of neonatal sepsis. The first symptoms of infection can make themselves felt very early, an hour or several after birth, but a delayed start is possible - days and weeks pass before listeriosis manifests itself.
Features of the development of pathology in a newborn
Observations have shown that more often the early development of listeriosis occurs in babies whose birth weight was very small. The risks are higher if there were complications during childbirth. An early start of the disease is observed if there are symptoms of sepsis, insufficiency of the functioning of the respiratory and cardiac systems.
If the baby is born on time, looks he althy at birth, the form of listeriosis is often delayed. Some time after birth, sepsis develops, meningitis is diagnosed.
Check
Assuminglisteriosis, it is necessary to take samples of organic tissues for culture isolation. From a sick woman, blood is taken for analysis, parts of the uterine cervix, a small amount of amniotic fluid, if such a fluid is available. This is necessary if the pregnant woman is diagnosed with a fever.
A newborn needs to take samples of blood and spinal cord fluid, aspirate obtained from the digestive system for research. You can examine infected tissue, meconium.
Diagnostic features
It is considered important to timely obtain samples of mucous secretions of the cervical canal, blood from women who suffered from a fever during pregnancy, and the cause could not be identified. If the mother has listeriosis, the infant should be examined for sepsis. To do this, you need to check any tissue for which the risk of infection is particularly high, the main body fluids.
In rare cases, the analysis shows an abundance of mononuclear cells, but in most cases polymorphonuclear cell structures are predominantly detected. Smears give a negative color in the study using the Gram technology. It is possible to detect coccobacilli, giving different color options for the analysis. In the laboratory, it is necessary to organize a biochemical test, to trace how microscopic life forms glide, move in semi-solid matter.
Treatment
In the case of an early start and an instantaneous course, the probability of a lethal outcome is higher. In the best scenarios for the development of the disease, the risk of mortality is estimated at10-50%, for those who develop severely and quickly the disease reaches 80%.
For treatment use aminoglycosides, combining them with ampicillin. As a rule, a two-week program is enough. If meningitis is among the symptoms, antibiotics are prescribed for a three-week course. At the moment, there is no exact confirmed information regarding the optimal duration of drug therapy. The doctor focuses on the manifestations and course of a particular case.
