The uniqueness and key role of mycolic acids in the structural organization and physiology of mycobacteria make them an excellent target for etiotropic therapy.

They reproduce by cell division. Widely distributed in soil. Saprophytic forms participate in the mineralization of organic residues, some oxidize paraffins and other hydrocarbons. Can be used to combat oil pollution of the biosphere.

Pigmentation

According to Runyon's classification of non-tuberculous mycobacteria based on cultural differences from 1959, according to pigment production by colonies, 4 groups of mycobacteria are distinguished:

Photochromogenic (Group I) Mycobacteria that are unpigmented when grown in the dark, but acquire bright yellow or yellow-orange pigmentation after exposure or reincubation in the light.

• Ex: M. kansasii, M. marinum, M. simiae, M. asiaticum

• Ex: M. scrofulaceum, M. gordonae, M. xenopi, M. szulgai

• Ex: M. tuberculosis, M. avium, M. intracellulare, M. bovis, M. ulcerans
• Ex: M. chelonae

• Ex: M. phlei, M. smegmatis, M. fortuitum

Pathogenic species

Pathogenic species cause diseases in humans (tuberculosis, leprosy, mycobacteriosis) and animals. A total of 74 species of such mycobacteria are known. They are widely distributed in soil, water and among people.

Tuberculosis in humans is caused by species : Mycobacterium tuberculosistypus(human species), Mycobacterium bovis(bull look) and Mycobacterium africanum(intermediate species), in patients with AIDS - also types Mycobacterium avium complex. These species are able to penetrate, live and reproduce inside humans.

Representatives of the genus Mycobacteria

According to the old system, mycobacteria were classified depending on their properties and growth rate on nutrient media. However, newer nomenclature is based on cladistics.

Slow growing

Mycobacterium tuberculosis complex (MTBC)

• Mycobacterium tuberculosis complex(MTBC) representatives of the complex are pathogenic for humans and animals, and cause the disease tuberculosis. The complex includes: M. tuberculosis, the most dangerous for humans as the causative agent of tuberculosis M. bovis M. bovis BCG M. africanum M. canetti M. caprae M. microti M. pinnipedii

Mycobacterium avium complex (MAC)

Mycobacterium avium complex (MAC)- part of a large group of non-tuberculous mycobacteria (NTMB), the species that make up this complex are pathogenic for humans and animals, more often cause disseminated processes of extrapulmonary localization and were previously one of the main causes of death in AIDS patients. The complex includes:

• M. avium M. avium paratuberculosis M. avium silvaticum M. avium "hominissuis" M. colombiens

Gordonae-branch

• M. asiaticum
• M. gordonae

Kansasii-branch

• M. gastri

Non-chromogenic/terrae-branch

• M. hiberniae
• M. nonchromogenicum
• M. terrae
• M. triviale

Mycobacteria producing mycolactone

• M. ulcerans
• M. pseudoshottsii
• M. shottsii

Simiae-branch

• M. triplex
• M. genavense
• M. florentinum
• M. lentiflavum
• M. palustre
• M. kubicae
• M. parascrofulaceum
• M. heidelbergense
• M. interjectum
• M. simiae

Uncategorized

• M. branderi
• M. cookies
• M. celatum
• M. bohemicum
• M. haemophilum

Fast growing

Сhelonae-branch

• M. abscessus
• M. chelonae
• M. bolletii

Fortuitum branch

• M. fortuitum
• M. fortuitum subsp. acetamidolyticum
• M. boenickei
• M. peregrinum
• M.porcinum
• M. senegalense
• M. septicum
• M. neworleansense
• M. houstonense
• M. mucogenicum
• M. mageritense
• M. brisbanense
• M. cosmeticum

Parafortuitum-branch

• M. parafortuitum
• M. austroafricanum
• M. diernhoferi
• M. hodleri
• M. neoaurum
• M. frederiksbergense

Vaccae-branch

• M. aurum
• M. vaccae

CF branch

• M. chitae
• M. fallax

Uncategorized

• M. confluentis
• M. flavescens
• M. madagascariense
• M. phlei
• M. smegmatis
  • M. goodii
  • M. wolinskyi
• M. thermoresistibile
• M. gadium
• M. komossense
• M. obuense
• M. sphagni
• M. agri
• M. aichiense
• M. alvei
• M. arupense
• M. brumae
• M. canariasense
• M. chubuense
• M. conceptionense
• M. duvalii
• M. elephantis
• M. gilvum
• M. hassiacum
• M. holsaticum
• M. immunogenum
• M. massiliense
• M. moriokaense
• M. psychrotolerans
• M. pyrenivorans
• M. vanbaalenii

Several billion years ago, tiny living creatures - bacteria - settled on Earth. They reigned on the planet for a long time, but the appearance of plants and animals disrupted the life activity habitual for microorganisms. We should pay tribute to the “kids” who managed to adapt to new conditions. Microorganisms, having settled in food, inside the human body, in water and air, have established very strong contact with humans. What consequences can people expect from interacting with them?

Nutritionists compile tables of proper nutrition, where they indicate the ratio of proteins, fats, calories and carbohydrates in ready-made meals. But there is one more component that is not mentioned there. This is the presence of beneficial bacteria.

The human large intestine contains microorganisms that actively participate in the digestion process. Normal microflora helps strengthen the immune system and increase vital activity. But failures in its operation lead to the fact that a person becomes defenseless against viruses and toxins.

You can support the body's little defenders by eating foods that contain probiotics. They are maximally adapted to the needs of the human body, where they carry out active sanitary activities. What healthy foods should you include in your diet?.jpg" alt="probiotics and prebiotics" width="300" height="178" srcset="" data-srcset="https://probakterii.ru/wp-content/uploads/2015/08/bakterii-v-produktah3-300x178..jpg 451w" sizes="(max-width: 300px) 100vw, 300px">!}

Varied selection

• pills;
• powders;
• capsules;
• suspensions.

A very important component in the diet

It is necessary to specifically focus on the benefits of lactic acid products. Thanks to the presence of lactic acid in it, it neutralizes putrefactive bacilli that want to cause damage to the human body. It is impossible to overestimate the role of lactic acid products in maintaining health. They are very easily digestible, protect the intestinal walls from the invasion of infections, promote the breakdown of carbohydrates and the synthesis of vitamins.

Lactic acid products are a real salvation for people suffering from intolerance to whole milk. Thanks to bifidobacteria, lactose and milk sugar are perfectly digested.

Fermented milk products contain vital nutrients:

• fats;
• amino acids;
• vitamins;
• proteins;
• carbohydrates;
• calcium.

In the process of preparing dairy products, biologically active substances are synthesized that prevent the appearance of malignant tumors.

The beneficial effects of dairy and fermented milk products can only be felt if they are consumed regularly. A proper diet should include dairy products several times a week. The body absorbs them well in combination with grain dishes containing carbohydrates.

How do pathogenic microbes get into food?

A hot dog or spoiled sausage purchased from a street stand can cause food poisoning, which is accompanied by the following symptoms:

• vomiting, nausea;
• chills;
• stool disorder;
• dizziness;
• weakness;
• stomach ache.

The causative agents of such serious ailments are bacteria. They can be found in raw meat, on the surface of fruits and vegetables. Semi-finished products are often subject to spoilage if storage rules are violated.

Food can become contaminated in food service establishments if workers do not wash their hands after using the toilet. Dishes displayed on display also run the risk of spoilage. After all, visitors may sneeze or cough while choosing their food.

Rodents, birds, and domestic animals often become carriers of diseases. When they come into contact with human food, they can contaminate it.

Pathogenic bacteria that cause poisoning multiply very quickly on the surface of tables, cutting boards, and knives. During the cooking process, crumbs remain on kitchen equipment, which are an excellent breeding ground for microbes, which causes food spoilage.

Protect yourself

Ideal conditions for bacterial growth are:

• moisture is a prerequisite for life;
• heat - develops well at room temperature;
• time – the number doubles every 20 minutes.

Food left at room temperature for long periods of time is an ideal environment for microbes to feed and multiply. Heated dishes can be consumed within 2 hours without harm to health, but reheating them is not recommended.

Spoilage of dairy products is indicated by a bitter taste and increased gas formation. If storage rules are violated, putrefactive microbes actively work to decompose the protein. Do not consume spoiled products, and especially do not risk giving them to children.

To protect yourself from serious illness, store raw and prepared foods separately in the refrigerator. Don't forget that food should be stored in special food containers with lids. In the absence of such containers, you can simply cover the finished dishes with cling film.

Be sure to wash your hands before preparing food. And treat work surfaces and equipment with special disinfectant solutions or boiling water..jpg" alt=" hand washing" width="300" height="199" srcset="" data-srcset="https://probakterii.ru/wp-content/uploads/2015/08/istochnik-bakterij4-300x199..jpg 746w" sizes="(max-width: 300px) 100vw, 300px">!}

Food must be defrosted until completely thawed. Otherwise, they will not undergo complete heat treatment. This means that pathogenic bacteria can multiply unhindered.

Leftover food can be stored for no more than two days. And only in the refrigerator. When preparing salads, it is strictly forbidden to add yesterday's surplus to them.

We choose wisely

When choosing fermented milk products in a store, carefully study the label. It contains information about the amount of fats, carbohydrates, proteins, and vitamins.

Pay attention to the shelf life: if the product does not spoil for more than two days, then it most likely does not contain live bacteria.

Choose natural products made from whole milk, rather than vegetable fats and starch, which are harmful to the body. Of course, it also contains fats and carbohydrates, but there are definitely no beneficial microorganisms there.

Interacting with bacteria in everyday life can bring great benefit or irreparable harm to a person. Therefore, you should never let your guard down. Don't be tempted to eat cream cakes sold right on the street under the scorching rays of the sun. Better go to the store and buy live yogurt (just wash your hands before eating!). And then your body will definitely thank you with excellent health and active life.

The causative agent of tuberculosis causes the development of a dangerous disease that destroys the human body and often leads to death. Mycobacterium has special vital functions: metabolism, nutrition, energy production, growth and reproduction, interaction with the outside world.

Description of the cell of the causative agent of tuberculosis

Acid-fast bacteria are rod-shaped, 1-4 microns in size, with a homogeneous or slightly granular consistency. Mycobacteria do not form capsules and endospores.

Comparative characteristics of Koch's bacillus make it possible to become familiar with the structural features of the cell wall, its phenotypic properties, relation to Gram staining, biochemical parameters, and antigen structure.

The pathogen belongs to the species Actinobacteria, genus Mycobacterium. The rod-shaped pathogen cell has a wall thickness of 0.5-2 microns. It is surrounded by a shell, which includes additional elements:

• cell capsule;
• microcapsule;
• slime.

The internal structure of a bacterial cell is complex and contains important structural elements. Its wall consists of peptidoglycan, a small amount of proteins and lipids.

The tuberculosis bacillus is a pathogenic actinomycete. The cell contains trace elements N, S, P, Ca, K, Mg, Fe and Mn.

The causative agent of tuberculosis and its properties, features, and routes of transmission have a direct impact on the diagnosis of the pathological process in the patient’s body.

Varieties of mycobacteria

Tuberculosis is caused by several types of bacteria:

• m. Tuberculosis;
• m. bovis;
• m. avium;
• t. murium.

Atypical mycobacteria causes tuberculosis in humans and is characterized by great demands on nutrient media. M. tuberculosis grows slowly in height on Petrov, Lowenstein-Jensen media, glycerin broth, l-glutamine without sodium bicarbonate.

Bacteria are found in R and S forms. For their growth, a liquid medium is used, in which a rough, wrinkled film is formed on the 15th day.

The following parameters are characteristic of a bacterial cell:

• low activity;
• the presence of a proteolytic enzyme that breaks down protein.

Koch's bacillus is the causative agent of a dangerous infection; it secretes an endotoxin called tuberculin. The substance discovered by R. Koch has an allergic effect on the diseased body and causes the appearance of symptoms characteristic of the tuberculosis process. Mycobacterium antigens contain protein, fat and polysaccharide components.

The tuberculosis bacterium can withstand temperatures up to +100°C, dies after 5-6 hours under the influence of ultraviolet rays, and persists in dried sputum for up to 12 months.

Features of the genus Mycobacterium

Bacteria that cause the development of a pathological process are classified according to several criteria:

• pigment produced by a microorganism;
• growth intensity;
• resistance to acids.

Among the characteristic features are its length, growth rate, pathogenicity, ability to reduce nitrates to nitrites, and the result of a niacin test (positive or negative).

Mycobacteria are a repository of:

• toxic substances;
• mycolic acid;
• phosphates;
• free fatty acids;
• glycosides;
• nucleoproteins.

The tuberculosis bacterium contains carbohydrates in the amount of 15-16% of the dry residue, and is cultivated on nutrient media that include egg yolk, potato starch, glycerin, and milk at a temperature of +37°C.

Nutrient media colonized with the causative agent of tuberculosis give rise to colonies within 10-15 days. Some species of mycobacteria are pathogenic for humans, and only m. avium does not have a specific effect, being the causative agent of the disease in birds.

Enzymatic urease activity can appear in M. tuberculosis, M. bovis, M. africanum. The niacin test is positive only for M. tuberculosis, which causes tuberculosis in 90% of cases.

Stability of Koch's bacillus

Mycobacterium tuberculosis is resistant to drugs. When symptoms of the disease appear, the doctor prescribes a combination of several medications to the patient. Koch's bacillus is found in many people's bodies, but strong immunity prevents its reproduction. Drug-resistant forms of bacteria can appear only if the treatment was not carried out in full or lasted less than 6 months.

If the patient does not take medication, a mutated type of Koch bacillus appears, giving rise to new populations. There is a form of the pathogen that causes a relapse of the disease, which is difficult to treat.

The persistence of Mycobacterium tuberculosis to the action of chemicals is caused by its adaptation to environmental conditions.

Numerous manifestations of pathogen resistance are associated with genes localized in the chromosome and plasmids.

Koch's bacillus constantly mutates, but antibiotics do not have a significant effect on the frequency of the process. Transfer of resistance plasmids from the pathogen to the cells of the human body increases the resistance of Koch's bacillus.

The causative agent of tuberculosis persists in raw milk for up to 2-3 weeks; when frozen, pathogenic properties appear after 30 years.

Mechanism of infection

Tuberculosis is caused by Koch's bacillus, which is transmitted in several ways:

• aerogenic;
• nutritional;
• contact;
• intrauterine.

Manifestations of an infection transmitted by airborne droplets are characterized by the release of droplets of mucus when the patient breathes. The alimentary route of infection is possible through the stomach and intestines.

Mycobacterium enters the body with food: the patient develops tuberculosis caused by consumption of dairy products (sour cream, cottage cheese). Contact route of infection is rare.

Pulmonary tuberculosis is not hereditary, but some people are predisposed to developing the disease. The pathological process begins after a person is infected with Mycobacterium tuberculosis, and its nature depends on the duration of contact with the patient. The disease occurs as a result of communication between people living in the same family for a long time. How quickly pulmonary tuberculosis develops depends on the clinical form of the disease, its phase, the patient’s living conditions, and the effectiveness of treatment.

Tuberculosis actively manifests itself in patients with fresh or chronic cavities. The disease is accompanied by massive secretion of Koch's bacillus with sputum. The tuberculosis process can occur in open or closed form.

The development of pulmonary tuberculosis depends on the characteristics of mycobacteria, the state of the patient’s immune system and the presence of concomitant diseases.

No matter where the introduction of Koch's bacillus came from, tuberculosis is dangerous for humans.

Reproduction of Koch's bacillus

In the human body, Mycobacterium tuberculosis retains the ability to reproduce. The process can be represented in two ways:

• budding;
• branching.

The process of bacterial division occurs within 15-20 hours, after which a daughter cell is formed. The increase in the number of pathogens is due to the synthesis of nutrients included in their composition.

Koch's bacillus is characterized by transverse division, accompanied by the formation of a septum. In a nutrient medium, the tuberculosis bacterium multiplies until any of its components reach their maximum value.

In this case, the growth and reproduction of Koch's bacillus stops. The logarithmic phase of cell division is usually provoked by the type of nutrient medium. Mycobacterium tuberculosis has a cell doubling time of 24 hours.

A bacterial culture consists of ordinary cells. In the stationary phase of reproduction, their number stops increasing. Mycobacteria can divide up to 50 times, and then the cell dies.

During the process of reproduction, the Koch virus forms granules located at the cell poles. A bulge is formed, occupying a significant part of the membrane. The tubercle gradually increases in size and separates from the mother cell.

The Koch virus, as scientists suggest, can reproduce by spores.

Cultural properties of the pathogen

The tuberculosis bacterium grows on solid and liquid nutrient media. Mycobacteria require constant access to oxygen, but sometimes colonies appear under anaerobic conditions. Their number is insignificant, growth is slow. The causative agent of tuberculosis can appear on the surface of a one-component substrate in the form of a wrinkled film. The nutrient medium satisfies the nutritional and energy needs of Mycobacterium tuberculosis.

Koch's bacillus can appear on a multicomponent substrate containing amino acids, mineral salts, carbohydrates, and glycerin. On solid media, mycobacteria appear as a dry, scaly gray coating with a specific odor.

Often the substrate colonized by the tuberculosis pathogen contains smooth colonies.

Antibacterial therapy affects the appearance of colonies: they become moist and pigmented. As soon as atypical cultures appear, a special test is immediately carried out to determine the pathogenicity of the pathogen.

The culture filtrate that appears on a liquid nutrient medium has one feature: it is toxic, because... releases a toxic substance into the environment. The disease in humans and animals exposed to its specific action is very severe.

Biochemical properties of Koch's bacillus

The microbe causing the infectious disease is identified using a niacin test. The test determines the presence of nicotinic acid in the extract of growing mycobacteria. The test for M. tuberculosis may be positive. To carry out the reaction, a reagent - 1 ml of a 10% aqueous solution of potassium cyanide - is added to the culture of mycobacteria in a liquid medium. If the reaction is positive, the extract becomes bright yellow.

Numerous strains of the pathogen that causes lung damage are highly virulent and quickly penetrate the patient’s body. Antigens of mycobacteria can cause the appearance of cord factor - glycolipids on the surface wall of the pathogen, which destroy the mitochondria of cells in the patient's body. In this case, the patient's respiratory function is impaired.

The tuberculosis bacterium does not produce endotoxin. The study of Koch's bacillus located in the patient's body is carried out using the bacteriostatic method.

The growth of the pathogen in cultured sputum populated by microorganisms lasts 90 days. Then the doctor evaluates the result obtained.

Ineffective treatment with anti-tuberculosis drugs leads to changes in the properties of the pathogen. Mycobacterium begins to grow and multiply in immune bodies, and the number of cases of open tuberculosis increases.

Tinctorial properties of Koch's bacillus

The tuberculosis bacterium is a gram-positive microorganism and is difficult to stain. It contains up to 40% fat, wax, and mycolic acid.

To establish an infection, the tuberculosis pathogen is stained with a special Ziehl-Neelsen method. In this case, Koch's wand becomes red.

The study of the tinctorial properties of the causative agent of tuberculosis is carried out using aniline dyes. During the examination of Koch's bacillus, homogeneous staining of the cytoplasm appears. Studying the pathogen allows us to determine the presence of a nucleus and other cellular structures.

The causative agent of tuberculosis is an aerobe and grows slowly on a multicomponent nutrient medium. During primary microscopy, Koch's bacillus can be identified and identified by morphological and tinctorial properties.

• Mycobacterium tuberculosis(Koch's bacillus) - pathogen human tuberculosis
• Mycobacterium leprae(Hansen's bacillus) - pathogen leprosy (leprosy)[A30.- ]
• Mycobacterium bovis- pathogen bovine tuberculosis And, less often, person
• Mycobacterium avium- causative agent of various mycobacterioses, tuberculosis in HIV-infected people, pulmonary infections[A31.0 ], mycobacterial gastritis and etc.
• Mycobacterium intracellulare And Mycobacterium kansasii- pathogens pulmonary infections[A31.0 ] and other mycobacterioses
• Mycobacterium ulcerans- pathogen Buruli ulcers[A31.1]
• Mycobacterium marinum- pathogen skin infections[A31.1]

Mycobacterial infections in gastroenterology

Intestinal tuberculosis

• anus and rectum † (K93.0*)
• intestine (large) (small) † (K93.0*)
• retroperitoneal (lymph nodes)

Note. In ICD-10, the main codes of the underlying disease are marked with a cross †, which must be used. An asterisk * indicates optional additional codes that relate to the manifestation of a disease in a separate organ or area of ​​the body that represents an independent clinical problem.

Intestinal tuberculosis is a chronic infectious disease caused by mycobacteria Mycobacterium tuberculosis. Usually it is a secondary process that occurs against the background of pulmonary tuberculosis. It manifests itself in the formation of specific granulomas in various parts of the intestine, most often in the ileocecal region.

Tuberculous ileotiphlitis (tuberculosis of the cecum) is a tuberculous lesion of the ileocecal region.

Although gastric damage due to tuberculosis is quite rare, in recent years there has been a significant increase in morbidity and mortality from this disease, due to a number of reasons:

• a sharp increase in population migration;
• insufficient level of anti-tuberculosis measures;
• increased incidence of tuberculosis caused by drug-resistant mycobacteria.

Stomach damage is more often observed in secondary tuberculosis, which is caused by the patient ingesting sputum containing mycobacteria. In addition, damage to the gastric mucosa may be a consequence of the spread of infection through the lymphatic vessels from the affected mesenteric lymph nodes.

The following forms of tuberculosis of the stomach are distinguished:

• ulcerative
• hypertrophic (tumor-like)
• fibrosclerotic
• ulcerative-hypertrophic (mixed)

Recognizing gastrointestinal tuberculosis is quite a difficult task. The diagnosis is verified primarily based on the results of bacteriological or histological examination. In addition to collecting an anamnesis aimed at identifying the connection of the disease with tuberculosis infection, it is necessary to use all diagnostic methods existing today: examination, percussion, palpation of the patient, identification of Mycobacterium tuberculosis in the contents of the stomach and intestines, tuberculin diagnostics, polymerase chain reaction to identify a specific pathogen, identification of blood antigens of mycobacteria and antibodies using immunological methods (enzyme immunoassay), radiological, instrumental methods, histological and bacteriological examination of biopsy material, sonography (Frolova-Romanyuk E.Yu.).

Gastritis and duodenitis caused by mycobacteria in promising classifications

In the section Infectious gastritis (infectious gastritis) there is a subsection Bacterial gastritis (bacterial), where, among other types of bacterial gastritis, the following is presented:

• Mycobacterial gastritis (mycobacterial gastritis)
• Tuberculous gastritis (tuberculous gastritis)
• Non-tuberculous mycobacterial gastritis (non-tuberculous mycobacterial gastritis)
• Mycobacterium avium-intracellulare gastritis (gastritis caused by infection Mycobacterium avium)
• Gastritis due to other specified non-tuberculous mycobacteria (gastritis due to infection with other non-tuberculous mycobacteria)

• Mycobacterial duodenitis (mycobacterial)
• Non-tuberculous mycobacterial duodenitis (non-tuberculous mycobacterial)
• Tuberculous duodenitis (duodenal tuberculosis)

Mycobacteria in modern* taxonomy of bacteria

After the discovery of the causative agent of tuberculosis - Mycobacterium tuberculosis - dozens of other types of mycobacteria were discovered. Most of them are distributed in nature. Many are saprophytes, some are pathogenic to fish, amphibians or birds, and only a few species cause disease in humans: Mycobacterium avium-intracellulare (most common), Mycobacterium kansasii, Mycobacterium marinum, and fast-growing mycobacteria such as Mycobacterium fortuitum and Mycobacterium chelonae. All are less virulent than Mycobacterium tuberculosis and usually cause opportunistic infections.

Identification of mycobacteria is based on the appearance of the colonies, growth rate and biochemical properties, but complex biochemical methods are gradually being replaced by molecular genetic methods, which quickly distinguish between Mycobacterium avium-intracellulare and Mycobacterium tuberculosis.

Mycobacterium avium-intracellulare

Chronic pulmonary infection. The disease usually occurs in middle age, more often in men. It resembles pulmonary tuberculosis, but has some differences. Symptoms of lung damage are common, but the general condition is rarely affected.

The disease flows and progresses slowly. On chest x-ray, changes are usually found in the lung parenchyma (thin-walled cavities, thickening of the pleura over the affected area), and pleural effusion occurs only occasionally. The disease is rarely diagnosed in the early stages. As a rule, an area of ​​the lung affected is affected by chronic bronchitis or bronchiectasis, emphysema, a healed focus of tuberculosis or silicosis.

Another form of the disease - damage to interstitial tissue and the formation of small nodular bronchiectasis in the middle and lower parts of the lungs - is observed in elderly women without chronic lung diseases. Other organs are rarely involved, although bone and joint infections occur in some cases. Since isolation of Mycobacterium avium-intracellulare does not prove the presence of infection, repeated isolation of large numbers of the same strain of mycobacterium over several days or weeks in combination with typical clinical and radiological symptoms is necessary to make a definitive diagnosis.

Due to the drug resistance of mycobacteria, treatment is often ineffective. If the flow is mild, it is best to limit yourself to observation. Advanced disease, accompanied by the formation of cavities in the lungs, often requires the prescription of three or more drugs for a long period, up to two years. When choosing a drug, you should, if possible, focus on the sensitivity of the pathogen. It is recommended to start treatment with a combination of clarithromycin (or azithromycin), rifabutin (or rifampicin) and ethambutol; streptomycin can be added at an early stage. Additional surgical intervention is appropriate for focal infection and minimal surgical risk.

Cervical lymphadenitis. The disease occurs in children aged 1 to 5 years and is manifested by persistent painless enlargement of the anterior or posterior cervical lymph nodes. Infection probably occurs through nutritional means when a child takes something into his mouth from the floor or ground. Infection with Mycobacterium avium-intracellulare is a much more common cause of granulomatous lymph node inflammation than tuberculosis. The diagnosis is made after isolation of the pathogen from material obtained during puncture or biopsy of enlarged lymph nodes. Antibiotics are ineffective. Without treatment, the disease often leads to the formation of fistulas or disfiguring scars.

Disseminated infection. This serious disease is sometimes observed in cancer patients and internal organ recipients during immunosuppressive therapy, but it poses the greatest danger to patients with AIDS. Disseminated infection develops when the CD4 count falls below 50 per microliter (and often below 10 per microliter), affecting 20-40% of patients. Clinical manifestations include high fever, weakness, diarrhea and pancytopenia (poor prognostic sign).

The most accurate diagnostic methods are blood or bone marrow culture. Stool culture is also usually positive, but in itself it has no diagnostic value.

Without treatment, 50% of patients live no more than 4 months. With combination antimicrobial therapy, like that used for chronic lung infections, survival can be doubled. During treatment, special complications often arise due to the interaction of rifampicin with antiretroviral drugs. In patients with AIDS whose CD4 lymphocyte count does not exceed 100 per μl, prophylaxis of disseminated infection with azithromycin is recommended.

Mycobacterium kansasii

Unlike Mycobacterium avium-intracellulare, which is widespread in soil and water bodies, Mycobacterium kansasii is rarely found in nature, but is occasionally found in tap water. The microorganism has the shape of a rosary or beads and is larger than other mycobacteria, so for an experienced laboratory doctor, a Ziehl-Neelsen stained smear is enough to make a diagnosis. Mycobacterium kansasii has a specific property - its culture turns yellow in the light (Mycobacterium kansasii is a photochromogenic mycobacterium).

The pathogenicity of Mycobacterium kansasii for humans is low. Like Mycobacterium avium-intracellulare, this organism can cause chronic pulmonary infection and disseminated infection in patients with AIDS and, rarely, infection of bones and joints. However, Mycobacterium kansasii differs from Mycobacterium avium-intracellulare in being more sensitive to antimicrobial drugs. Rifampicin has a significant effect, and the currently recommended treatment regimen includes rifampicin, isoniazid, and ethambutol for at least 9 months.

Mycobacterium marinum

A disease caused by Mycobacterium marinum, swimmer's granuloma, is characterized by the appearance of nodules and ulcerations on the skin. Infection occurs during swimming, cutting sea fish, or cleaning the aquarium. Diagnosis is made after isolation of Mycobacterium marinum from a skin biopsy.

The disease may go away on its own, but deep lesions (tenosynovitis or arthritis) must be treated for at least 3 months. The pathogen is usually sensitive to clarithromycin, trimethoprim/sulfamethoxazole, tetracycline, rifampicin and ethambutol. You can prescribe any one of these drugs or a combination of rifampicin and ethambutol.

Fast growing mycobacteria

Fast-growing mycobacteria, primarily Mycobacterium fortuitum and Mycobacterium chelonae, cause wound infections and infections of endoprostheses, especially breast prostheses, tunneled catheters, porcine valves and surgical wax. Sometimes an eye or skin infection is also seen in combination with a lung infection similar to that caused by Mycobacterium aviumintracellulare.

Diagnosis is usually not difficult. It is not difficult to grow the pathogen; colonies form in 3-7 days.

Treatment usually involves removing the endoprosthesis and wide excision of the affected tissue. Antimicrobial therapy is not always effective; success is most likely with drugs such as amikacin, tobramycin, cefoxitin, sulfamethoxazole, imipenem, and ciprofloxacin.

Prof. D. Nobel

“Respiratory infections caused by atypical mycobacteria” - article from the section