Definition, toxonomic affiliation of mushrooms

In the air, fungal spores of this genus are present almost constantly: every day, each of us inhales about several hundred spores that do not cause any disease in a person with a normal immune system. And Sometimes fungi of the genus Aspergillus can be found in the oropharynx of a healthy person.

As already described above, fungal spores can be present in indoor air, including hospital air, which can be a risk factor for nosocomial infection of a hospital patient with a weakened immune system.

A number of representatives of fungi are used in industry for the production of organic acids, antibiotics, vitamins, enzymes, and for the industrial manufacture of certain food products.

Appearance description

Outwardly, when microscopically examined, fungi of the genus Aspergillus are fungi consisting of the same type of mycelium, 4-6 micrometers wide, on which sometimes there are “heads” with conidia.

A specific bacteriological nutrient medium for growing colonies of fungi of this genus is the so-called Sabouraud medium. On it, mushrooms form flat colonies, at first white, slightly fluffy, which subsequently take on bluish, yellowish, brown and other colors, depending on the species. Their surface becomes powdery.

Clinical Significance

A feature of this genus of fungi is the ability to cause not only allergic diseases, but also infectious lesions.

In terms of the frequency of development of specific infectious diseases, fungi of the genus Aspergillus rank second after yeast-like fungi of the genus Candida.

Predisposing factors for the development of Aspergillus infections are immunodeficiencies, including secondary immunodeficiencies while taking high doses of systemic glucocorticosteroids, for which the cellular and molecular mechanisms of the increased vulnerability of organs and tissues to fungal spores, as well as chronic lung diseases, have been studied.

Aspergillus can affect any organs and tissues.

Clinical manifestations include the following forms:

• bronchopulmonary aspergillosis and its varieties: infectious-allergic bronchopulmonary aspergillosis, purulent bronchitis, chronic aspergilloma, invasive pulmonary aspergillosis, chronic necrotizing pulmonary aspergillosis;
• generalized (septic) aspergillosis, which occurs in immunocompromised people (for example, with HIV infection) and has a high death rate;
• aspergillosis of ENT organs: otitis externa and otitis media, rhinosinusitis, laryngeal aspergillosis;
• aspergillosis of the eye;
• aspergillosis of the skin in the form of erythematous scales and papules, in more severe cases - necrotic lesions of the subcutaneous fatty tissue;
• bone aspergillosis;
• other forms of aspergillosis (damage to the mucous membranes of the mouth, genitals, mycotoxicosis).

The most common respiratory lesions occur against the background of chronic lung diseases:

• bronchial asthma, cystic fibrosis - for allergic bronchopulmonary aspergillosis;
• pre-existing cavities in the lungs (tuberculous cavities, cavities in patients with sarcoidosis or other diseases that sporulate cavity formation) - for aspergilloma;
• chronic obstructive pulmonary disease against the background of its treatment with glucocorticosteroids - for necrotizing pulmonary aspergillosis.

Risk factors for the occurrence of invasive pulmonary aspergillosis, in addition to those listed above, are secondary immunodeficiency states, against the background of treatment with immunosuppressants, HIV infection, decompensated diabetes mellitus, massive antibiotic treatment and other factors.

However, people with normal immune systems can also develop respiratory infections with Aspergillus due to increased exposure to fungal spores.

Massive inhalation of the spores of these fungi in healthy people can cause acute pneumonia, which usually resolves on its own.

Occupational risk factors for chronic diseases caused by Aspergillus spores are work in agriculture, weaving mills and paper mills.

For fungi of the genus Aspergillus, this disease is called "the lung of workers with malt" due to the high frequency of occupationally caused cases of diseases in these workers.

Also, some representatives of fungi of this genus can release toxic substances - aflatoxin, ochratoxin and sterigmatocystin, which, when chronically exposed, cause manifestations of mycotoxicosis - toxic hepatitis, kidney disease, and even.

However, the main feature of fungi of the genus Aspergillus, which distinguishes them from representatives of other genera of mold fungi, is the ability to cause specific infectious diseases.

The main allergens and pathogenicity factors of fungi

Atopic diseases associated with sensitization to allergens of fungi of the genus Aspergillus are associated with the presence of allergens for which class E immunoglobulins are produced.

The number of main allergens varies depending on the species and in Aspergillus fumigatus reaches 19. The main ones are Asp f 1-ribotoxin, Asp f 3-peroxisomal protein, Asp f 5-metalloprotease and a number of other allergens, most of which are proteins with enzymatic activity .

The release of proteolytic, saccharolytic and lipolytic enzymes into the environment is a factor that determines the ability to cause an active infectious process, to show invasive growth, for example, to grow into the wall of the bronchus to the basement membrane in invasive bronchopulmonary aspergillosis.

Another factor in the virulence (ability to cause an infectious disease) of fungi is a number of defense mechanisms against phagocytosis (absorption by effector cells of innate immunity).

AT recent times The ability of the fungus Aspergillus fumigatus to form a protective film, which allows the cells of the fungus to attach to the cells of the host organism, provides protection against the effector mechanisms of immunity and even against modern antifungal drugs, is being intensively studied.

Above, a number of toxic substances secreted by some representatives of fungi of this genus were indicated.

Methods for detecting fungi and diagnosing diseases caused by fungi

Determination of belonging of fungal spores in air samples to representatives of the genus Aspergillus is based on microscopy of spores, bacteriological studies (determination of the ability to grow on a special nutrient medium, appearance colonies).

Due to the high frequency of allergic diseases and the severe course of specific infections caused by these fungi, they often lack specific clinical signs and complexity of differential diagnosis, great importance has specific .

Atopic sensitization to the allergens of these fungi is detected through skin tests and the detection of specific immunoglobulins E to the allergens of these fungi, antibodies of other classes in specific infectious processes.

For infections of the respiratory organs caused by fungi, microscopy of sputum and material obtained during broncho-alveolar lavage during bronchoscopy, detection of fungal DNA in the above materials using a polymerase chain reaction (PCR study) are used to identify fragments of the fungus.) under conditions of massive contact with house dust, contact with foci of high humidity during cleaning is necessary not only for allergy sufferers with sensitization to mold allergens, but also for all patients with bronchial asthma.

AT Everyday life a person often meets with various types of spore-forming fungi, which include fungi of the genus aspergillus. These pathogenic bacteria live everywhere, that is, both indoors and outdoors.

For humans, they are dangerous because they can cause a number of diseases, including

Scientists have more than 180 types of aspergillus, The following are the most dangerous to human health:

1. A. fumigatus.
2. A. flavus.
3. A. ochraceus.
4. A. nidulans.
5. A. oryzae.
6. A. glaucus.
7. A. niger.

Aspergillus fumigatus

These types of moldy fungi contribute to the appearance of allergic reactions in humans and a variety of specific infections.

Aspergillus live in the soil, domestic household dust, thereby developing in humans an allergy to house dust, rotting vegetables, building materials, textiles, some food products.

The spores of these fungi are constantly in the air, for a person with strong immunity they pose no danger, as they penetrate the body with every breath, but for those whose immune system for some reason cannot function normally, they threaten the development of serious diseases.

Some of the fungi of this genus are used for the development of medical drugs. Once in the nutrient medium, these microorganisms form colonies, their shape is at first white in texture, flat and slightly fluffy, then, depending on their species, they acquire a color that can be yellow, brown and blue.

For a person with a weakened immune system, the ingress of aspergillus into the body threatens the development of the following diseases:

1. Aspergillosis of the eye.
2. Aspergillosis of the bones.
3. Aspergillosis of ENT organs.
4. skin aspergillosis.
5. Bronchopulmonary aspergillosis.
6. Invasive pulmonary aspergillosis.

A number of factors contribute to the development of these diseases, such as:

1. Bronchial asthma.
2. Diabetes.
3. Oncological diseases.

Diagnosis and detection of diseases caused by these fungi is carried out in laboratories. For this, skin tests are done, sputum is taken for analysis in case of diseases of the respiratory system, and the same methods for diagnosing bronchial asthma in children and adults are also used.

Varieties of Aspergillus Mushrooms

Aspergillus niger

In science, there are many types of this moldy fungus. This article describes only some of them. Most people are wondering what it is. aspergillus fumigatus, since many people know that this particular type of fungus, which lives like the rest in water, soil and air, causes invasive pulmonary aspergillosis, allergic bronchopulmonary aspergillosis and aspergilloma.

Another type is the fungus. aspergillus niger, what it is is also a relevant question for him, although he is found in nature much less frequently than his previous counterpart. This variety lives in the soil, old cold rooms, air conditioners and books, bathrooms, basements, settles in tile joints, in pots where indoor plants grow.

Its other name is aspergillus black or black mold. The spores of this fungus move with the help of air and enter the human body when breathing.

This microorganism is the main provocateur of mold allergies, it also contributes to the development of bronchial asthma, rhinitis, pneumonia, the formation of papillomas and cancer cells, and meningitis.

With the answer to the question of aspergillus flavus that it is best of all, in addition to medical workers and scientists, people of the following professions are familiar:

1. Farmers.
2. Cheese workers.
3. Workers employed in breweries and flour mills.

The main distinguishing feature of this type of fungus is that, in addition to pillows, textiles, and old books, it also lives in grains of wheat and legumes. Mushrooms are formed at the time when the crop is harvested, transported and prepared for storage.

Most often, aspergillus flavus also affects the respiratory system, less often the cardiovascular system and the central nervous system.

Aspergillus nidulans

Another variety is aspergillus nidulans, which is also called a moldy fungus, its habitat is both the external environment, that is, air, water bodies, and the internal, that is, living quarters. It is also detrimental to the organs of the respiratory system, provokes the development of allergic conjunctivitis, rhinitis.

If a person has an allergic reaction to the above types of fungi, as well as to aspergillus oryzae, aspergillus ochraceus, aspergillus glaucus it is urgently required to remove sour cream, yogurts, kefir from his diet, yeast dough, smoked products, some types of cheeses, kvass, wines, beer, dried fruits. It should also be treated with caution with penicillin antibiotics..

These types of moldy spore-forming fungi, also known as black and smoking aspergillus, are nothing more than black mold, which not only spoils the interior of the home, but also undermines the health of the person living in it.

Aspergillus black settles on the walls in damp rooms, bathrooms, basements, air conditioners. Aspergillus fuming prefers to settle on food, such as baked goods.

These varieties of fungi, including kelp sphagnum, are strong allergens and can cause a number of serious, intractable diseases in humans, affecting their respiratory organs.

As for the differences between each species of fungus, they are not very significant, since any species prefers to settle in similar places of dwelling or external environment, all of them enter the body when inhaled, cause diseases associated with the respiratory system.

In any case, a person who has discovered that he has a health problem from the respiratory tract should visit a specialist as soon as possible, pass the necessary conditions and receive adequate, result-oriented treatment.

It is also worth mentioning that the development and reproduction of colonies of moldy mushrooms in the house is facilitated by temperatures from 18 to 25 degrees, high humidity more than 70 percent, poor performance of ventilation systems.

Invasive pulmonary aspergillosis

You need to take care of the cleanliness of your home, regularly ventilate the room, do wet cleaning, and if a fungus appears, then eliminate it. UV lamps are the best way to get rid of Aspergillus, before you treat your apartment with it, you need to remove pets and houseplants from it. If this type of treatment is not possible, the mold can be cleaned with soda, borax, hydrogen peroxide, bleach.

Spore-forming fungi have a particularly negative effect on the child's body due to the fact that the child's immunity is not strong enough and cannot independently cope with some pathogenic bacteria.

In contact with

Aspergillosis is a fungal disease caused by fungi of the genus Aspergillus that affects humans and manifests itself in the appearance of primary foci in the lung tissue, a variety of clinical lesions that, in case of severe immunodeficiency, can lead to lethal outcome.

Mushrooms of the genus Aspergillus are widely distributed in nature and are found in soil, hay, grain, dust of various premises, especially after processing animal skins and hair. An important epidemiological point is their frequent sowing in dust particles of medical institutions, which determines the possibility of nosocomial fungal infections.

Causes of Aspergillosis

The causative agent is mold fungi of the genus Aspergillus, the most common representative of which is Aspergillus fumigatus (80% of all cases of aspergillosis), less often Aspergillus vlavus, Aspergillus niger and others. Mushrooms of the genus Aspergillus (or Aspergillus spp.) belong to mold fungi, are heat-resistant, a favorable condition for existence is high humidity. Fungi of the genus Aspergillus are often found in residential areas, often found on the surface of unsuitable food products. The pathogenic properties of aspergillus are determined by the ability to secrete allergens, which is manifested by severe allergic reactions, lung damage, an example of which can be bronchopulmonary aspergillosis. Also, some of the representatives of fungi can secrete endotoxin that can cause intoxication. Aspergillus are resistant to desiccation, can be stored in dust particles for a long time. Detrimental to fungi are solutions of formalin and carbolic acid.

The mechanism of infection is aerogenic, and the main route is air-dust: with dust particles, fungi of this genus enter the respiratory tract. There are occupational risk groups for aspergillosis infection: agricultural workers; employees of weaving mills and spinning enterprises, as well as immunocompromised patients of medical hospitals who are at risk of nosocomial infection.

An additional mechanism of infection is endogenous infection with aspergillus in case fungi of this genus are already present on the mucous membranes. The main factor contributing to the endogenous spread of the infection is immunodeficiency, in which in 25% of cases mycoses of various etiologies develop, but the main share of which (up to 75%) is aspergillosis.

A person with aspergillosis is not contagious to others, such cases have not been described.

The susceptibility of the population is universal, however, people with weakened immunity become ill during chronic diseases, oncological processes, after transplantation of organs and tissues, with HIV infection and others. Seasonality in aspergillosis was not noted.

Immunity after an infection is unstable, repeated diseases occur in the group of immunodeficient patients.

The pathogenic effect of Aspergillus spp. per person

The entrance gate of infection in the vast majority of cases is the mucous membrane of the upper respiratory tract. At first, aspergillus are located superficially, then they deepen, causing ulceration of the mucous membrane.

Aspergillosis, site of injury

1) Even in a healthy person, when a large concentration of aspergillus spores is inhaled, pneumonia can develop - interstitial pneumonia. A distinctive feature of interstitial pneumonia in aspergillosis is the formation of specific granulomas consisting of giant epithelial cells (the so-called epithelioid cell granulomas). Aspergillus granulomas (aspergilloma) are spherical in shape and are centrally located foci of purulent inflammation, in which fungal hyphae are located, and giant cells along the periphery. Aspergilloma localization sites are the upper parts of the lungs, which is confirmed on the x-ray. Fungi are found in the affected bronchial mucosa, in lung cavities, bronchiectasis foci and cysts; in this form, fungi do not penetrate into the lung tissue (non-invasive aspergillosis).

2) In parallel with the defeat of the respiratory system in aspergillosis, there is a decrease in the immunological reactivity of the body (immunodeficiency). Cases of complications of concomitant diseases are described internal organs, mucous membranes and skin. An example is lung abscesses, chronic bronchitis, bronchiectasis, lung cancer, tuberculosis, against which a pulmonary form of aspergillosis arose, which, of course, caused a complication of the main process. Recent decades show the incidence of aspergillosis in immunocompromised individuals (HIV-infected, cancer patients receiving immunosuppressive therapy, organ recipients).

3) One of the possible lesions in aspergillosis is damage to internal organs and systems (invasive aspergillosis), which occurs in the overwhelming majority of cases against the background of a significant decrease in immunity. Up to 90% of patients with this lesion have two of the possible three features:
the number of granulocytes in the blood is less than 500 cells in 1 µl;
therapy with high doses of glucocorticosteroids;
cytostatic therapy.
In invasive aspergillosis, aspergilloma can form in internal organs. The drift of fungi occurs hematogenously (with blood flow). First, the lungs are affected, followed by the pleura, lymph nodes and other internal organs. Feature - the possibility of the formation of abscesses at the site of granulomas in most cases. The nature of the process resembles septic, in which mortality is quite high (up to 50%).

4) Allergic restructuring of the body - fungal antigens are powerful allergens that can cause allergic reactions with a primary lesion of the bronchopulmonary tree.

Symptoms of aspergillosis

Aspergillosis is classified as invasive (more often the sites of pathogen penetration are affected - the sinuses, skin, lower respiratory tract), saprophytic (otomycosis, pulmonary aspergilloma) and allergic (bronchopulmonary allergic aspergillosis, aspergillus sinusitis).

Clinically, the following forms of the disease are distinguished:
1) bronchopulmonary form;
2) septic form;
3) eye form;
4) skin form;
5) defeat of ENT organs;
6) damage to bones;
7) other more rare forms of aspergillosis (damage to the mucous membranes oral cavity, reproductive system, etc.).

Bronchopulmonary form- the most common form of aspergillosis, characterized by symptoms of tracheitis, bronchitis or tracheobronchitis. Patients complain of weakness, cough with sputum gray color, possibly with streaks of blood, with small lumps (clusters of fungi). The course of the disease is chronic. Without specific treatment, the disease begins to progress - the lungs are affected with the onset of pneumonia. Pneumonia develops either acutely or complicates the course of a chronic process. In its acute occurrence, the patient's temperature rises to 38-39 ° C, fever of the wrong type (maximum in the morning or afternoon, and not in the evening, as usual). The patient is shivering, worried about a pronounced cough with viscous sputum of a mucopurulent nature or with blood, shortness of breath, chest pain when coughing and breathing, weight loss, lack of appetite, increasing weakness, profuse sweating. On examination, moist small bubbling rales, pleural friction noise, shortening of percussion sound are heard.

Aspergillosis, bronchopulmonary form

Sputum microscopy reveals greenish-grayish lumps containing accumulations of aspergillus mycelium. In the peripheral blood, pronounced leukocytosis (up to 20 * 109 / l and above), an increase in ESR, an increase in eosinophils. Radiologically - inflammatory infiltrates of round or oval shapes with an infiltrative shaft along the periphery, with a tendency to disintegrate.

In the chronic course of aspergillosis, violent symptoms do not occur, the fungal process more often overlaps with an existing lesion (bronchiectasis, abscess, etc.). Patients often complain about the smell of mold from the mouth, a change in the nature of sputum with greenish lumps. Only radiologically, the appearance of spherical shading in the existing cavities with the presence of an air gas layer with the walls of the cavity is noted - the so-called "crescent halo".

Pulmonary aspergillosis, crescent halo

The prognosis of recovery in bronchopulmonary form depends on the severity of the course of the process and the state of immunity and ranges from 25 to 40%.

Septic form of aspergillosis occurs with a sharp suppression of immunity (for example, the stage of AIDS with HIV infection). The process proceeds according to the type of fungal sepsis. Along with the primary lesion of the lungs, the involvement of the internal organs and systems of the patient's body in the process is progressively increasing, the spread of the fungal infection occurs hematogenously. According to the frequency of damage, this digestive system- gastritis, gastroenteritis, enterocolitis, in which patients complain of an unpleasant smell of mold from the mouth, nausea, vomiting, stool disorders with the release of loose stools with foam containing mycelium of the fungus. Often there are lesions of the skin, organs of vision (specific uveitis), brain (aspergilloma in the brain). If aspergillosis develops in an HIV-infected person, then the disease is accompanied by other opportunistic infections (candidiasis, cryptosporidiosis, pneumocystis pneumonia, Kaposi's sarcoma, herpes infection). The prognosis for the disease is often unfavorable.

Aspergillosis ENT organs proceeds with the development of external and middle otitis media, damage to the paranasal sinuses - sinusitis, larynx. When the eyes are affected, specific uveitis, keratitis, and less often endophthalmitis are formed. Other forms of the disease are extremely rare. Aspergillosis of the skeletal system is manifested by the occurrence of septic arthritis, osteomyelitis.

Features of the course of aspergillosis in HIV-infected patients.

Aspergillosis is the most common form of fungal infections in this group of patients. All patients are in the last stage of HIV infection - the stage of AIDS. Aspergillus sepsis develops rapidly, with a severe course and prognosis. The CD4 count usually does not exceed 50/µl. X-ray revealed bilateral focal shading of a spherical shape. Along with the lungs, the organs of hearing (otomycosis) are affected, visual impairment with the development of keratitis, uveitis, endophthalmitis, and the cardiovascular system can often be affected (fungal damage to the valvular apparatus of the heart, endocarditis, myocarditis).

Complications of aspergillosis occur in the absence of specific treatment and against the background of immunodeficiency and represent the occurrence of extensive abscesses, chronic obstructive pulmonary disease, pulmonary fibrosis, damage to internal organs.
The prognosis of the disease in immunodeficiencies is unfavorable.

Diagnosis of aspergillosis

The preliminary diagnosis is clinical and epidemiological. The appearance of certain symptoms of the disease in combination with data on the presence of a specific profession, the presence of a concomitant disease and immunosuppressive therapy, as well as severe immunodeficiency, incline the doctor in favor of possible aspergillosis.

The final diagnosis requires laboratory confirmation of the disease.
1) Mycological examination of the material (sputum, bronchial material - swabs, biopsies of the affected organs, scrapings of the mucous membranes, smears-imprints). From the blood, the isolation of fungi is rare, so a diagnostic blood test is of no value.
2) Serological examination of blood to detect antibodies to aspergillus (ELISA, RSK), an increase in the concentration of IgE.
3) Paraclinical studies: general analysis blood: leukocytosis, eosinophilia, increased ESR.
4) Instrumental studies: X-ray examination, CT scan of the lungs (detection of spherical or oval-shaped unilateral or symmetrical volumetric infiltrates, detection of spherical infiltrates in previously existing cavities with crescent-shaped enlightenment along the periphery).
5) Special studies: bronchoscopy, bronchial washings, bronchoalveolar lavage or transthoracic aspiration biopsy, followed by examination of samples in order to identify pathomorphological changes: histologically, foci of necrosis, hemorrhagic infarcts, vascular lesions of an invasive nature, detection of aspergillus hyphae are detected.

Aspergillosis, fungus growth in material

Differential diagnosis is carried out with lung lesions of another fungal etiology (candidiasis, histopalismosis), pulmonary tuberculosis, lung cancer, lung abscess and others.

Aspergillosis treatment

Organizational and regime measures include hospitalization according to indications (severe forms of the disease, invasive aspergillosis), bed rest for the entire febrile period, and a complete diet.

Therapeutic measures include surgical methods and conservative therapy.

1) Conservative drug therapy is a difficult task and is represented by the appointment of antimycotic drugs: itraconazole 400 mg / day orally in long courses, amphotericin B 1-1.5 g / kg / day intravenously with severe immunodeficiencies, voriconazole 4-6 mg / kg 2 r / day intravenously, pospaconazole 200 mg 3 r / day orally, caspofungin 70 mg-50 mg intravenously. Against the background of treatment, titers of antibodies to aspergillus tend to increase, followed by a gradual decrease. The therapy is supplemented with general strengthening drugs, vitamin therapy. All drugs have contraindications and are prescribed exclusively by a doctor and under his control.

2) Surgical methods: lobectomy with removal of the affected areas of the lung.
Often, such methods are effective and are confirmed by the absence of recurrence of the disease. When the process spreads, conservative therapy is connected.

The effectiveness of treatment is higher when using the possibility of reducing the dosages of concomitant glucocorticosteroid and immunosuppressive therapy.

Prevention of aspergillosis

1) Timely and early diagnosis of the disease, timely start of specific treatment.
2) Carrying out medical examinations in occupational risk groups (agricultural workers, employees of weaving mills and spinning enterprises).
3) Alertness in terms of possible aspergillosis in a group of people suffering from immunodeficiencies while receiving immunosuppressive therapy, severe infections (HIV and others). Positive serological tests for antibodies to aspergillus require a thorough examination of the patient for the disease.

Infectious disease specialist Bykova N.I.

- mycosis caused by various types of mold fungi of the genus Aspergillus and proceeding with chronic toxic-allergic manifestations. With aspergillosis, the bronchopulmonary system and paranasal sinuses are predominantly affected; less often - skin, visual system, central nervous system, etc. Patients with low immune reactivity may develop disseminated aspergillosis. The leading role in the diagnosis of aspergillosis is played by laboratory methods: microscopy, culture, serological reactions, PCR. It is possible to perform inhalation and skin-allergic tests. Aspergillosis is treated with antifungal drugs.

ICD-10

B44

General information

fungal disease, the causative agent of which is the mold fungi aspergillus. Aspergillus can cause a variety of superficial and deep mycoses of internal organs, skin and mucous membranes, so aspergillosis is studied in a number of clinical disciplines: mycology, pulmonology, otolaryngology, dermatology, ophthalmology, etc. Over the past two decades, the frequency of aspergillosis infection in the population has increased by 20 %, which is associated with an increase in the number of patients with congenital and acquired immunodeficiency, the spread of drug addiction and HIV infection, the irrational use of antibiotics, the use of immunosuppressive drugs in oncology and transplantology. All this once again confirms the growing relevance of aspergillosis.

Causes of aspergillosis

The causative agents of aspergillosis in humans can be the following types of mold fungi of the genus Aspergillus: A. flavus, A. Niger, A. Fumigatus, A. nidulans. A. terreus, A. clavatus. Aspergillus are aerobes and heterotrophs; able to grow at temperatures up to 50°C, to persist for a long time when dried and frozen. AT environment aspergillus are ubiquitous - in soil, air, water. Favorable conditions for the growth and reproduction of aspergillus are found in ventilation and shower systems, air conditioners and air humidifiers, old things and books, damp walls and ceilings, long-term food products, agricultural and indoor plants and etc.

Infection with aspergillosis most often occurs by inhalation by inhalation of dust particles containing the mycelium of the fungus. Agricultural workers, workers in paper-spinning and weaving factories, flour millers, and pigeon breeders are most at risk of developing the disease, since pigeons, more often than other birds, suffer from aspergillosis. The occurrence of a fungal infection is facilitated by infection during invasive procedures: bronchoscopy, puncture of the paranasal sinuses, endoscopic biopsy, etc. The contact route of transmission of aspergillosis through damaged skin and mucous membranes is not excluded. Alimentary infection is also possible when eating foodstuffs contaminated with aspergillus (for example, chicken meat).

In addition to exogenous infection with aspergillus, cases of autoinfection (when activated by fungi that live on the skin, mucous membranes of the throat and respiratory tract) and transplacental infection are known. Risk factors for aspergillosis include immunodeficiencies of any origin, chronic diseases respiratory system (COPD, tuberculosis, bronchiectasis, bronchial asthma, etc.), diabetes mellitus, dysbacteriosis, burn injuries; taking antibiotics, corticosteroids and cytostatics, conducting radiation therapy. There are frequent cases of the development of mycoses of mixed etiology, caused by various types of fungi - aspergillus, candida, actinomycetes.

Aspergillosis classification

Thus, depending on the ways of spreading the fungal infection, endogenous (autoinfection), exogenous (with airborne and alimentary transmission) and transplacental aspergillosis (with a vertical infection) are distinguished.

According to the localization of the pathological process, the following forms of aspergillosis are distinguished: bronchopulmonary (including pulmonary aspergillosis), ENT organs, skin, eye, bone, septic (generalized), etc. The primary lesion of the respiratory tract and lungs accounts for about 90% of all cases aspergillosis; paranasal sinuses - 5%. Involvement of other organs is diagnosed in less than 5% of patients; dissemination of aspergillosis develops in approximately 30% of cases, mainly in debilitated individuals with a burdened premorbid background.

Symptoms of aspergillosis

The most studied form of pathology to date is pulmonary aspergillosis. Initial stages bronchopulmonary aspergillosis are disguised as a clinic of tracheobronchitis or bronchitis. Patients are concerned about coughing with grayish sputum, hemoptysis, general weakness, weight loss. When the process spreads to the lungs, a pulmonary form of mycosis develops - Aspergillus pneumonia. In the acute phase, there is fever of the wrong type, chills, cough with copious mucopurulent sputum, shortness of breath, chest pain. When breathing from the mouth, there may be a smell of mold. With the help of microscopic examination of sputum, colonies of mycelium and aspergillus spores are detected.

In patients with concomitant diseases of the respiratory system (pulmonary fibrosis, emphysema, cysts, lung abscess, sarcoidosis, tuberculosis, hypoplasia, histoplasmosis), pulmonary aspergilloma is often formed - an encapsulated focus containing fungal hyphae, fibrin, mucus and cellular elements. The death of patients with aspergilloma can occur as a result of pulmonary hemorrhage or asphyxia.

Aspergillosis of the ENT organs can occur in the form of otitis externa or otitis media, rhinitis, sinusitis, tonsillitis, pharyngitis. With aspergillus otitis, hyperemia, peeling and itching of the skin of the external auditory canal first occur. Over time, the ear canal is filled with a loose grayish mass containing filaments and spores of the fungus. It is possible to spread aspergillosis to the eardrum, accompanied by sharp stabbing pains in the ear. The lesions of the maxillary and sphenoid sinuses, the ethmoid bone, the transition of fungal invasion to the orbits are described. Ocular aspergillosis can take the form of conjunctivitis, ulcerative blepharitis, nodular keratitis, dacryocystitis, blepharomeibomitis, panophthalmitis. Complications in the form of deep corneal ulcers, uveitis, glaucoma, vision loss are not uncommon.

Aspergillosis of the skin is characterized by the appearance of erythema, infiltration, brownish scales, and moderate itching. In the case of the development of onychomycosis, deformation of the nail plates occurs, a change in color to dark yellow or brownish-greenish, crumbling of the nails. Aspergillosis of the gastrointestinal tract proceeds under the guise of erosive gastritis or enterocolitis: it is characterized by the smell of mold from the mouth, nausea, vomiting, and diarrhea.

The generalized form of aspergillosis develops with hematogenous dissemination of aspergillus from the primary focus to various organs and tissues. With this form of the disease, aspergillus endocarditis, meningitis, encephalitis occur; abscesses of the brain, kidneys, liver, myocardium; damage to bones, gastrointestinal tract, ENT organs; aspergillus sepsis. Mortality from septic aspergillosis is very high.

Diagnosis of aspergillosis

Depending on the form of mycosis, patients are referred for a consultation with a specialist of the appropriate profile: pulmonologist, otolaryngologist, ophthalmologist, mycologist. In the process of diagnosing aspergillosis, much attention is paid to the anamnesis, including professional history, the presence of chronic pulmonary pathology and immunodeficiency. If a bronchopulmonary form of aspergillosis is suspected, radiography and CT of the lungs, bronchoscopy with sputum sampling, bronchoalveolar lavage are performed.

The basis for the diagnosis of aspergillosis is a complex of laboratory studies, the material for which can be sputum, washings from the bronchi, scrapings from smooth skin and nails, discharge from the sinuses and external auditory canal, prints from the surface of the cornea, feces, etc. Aspergillus can be detected with using microscopy, cultural studies, PCR, serological reactions (ELISA, RSK, RIA). It is possible to carry out skin-allergic tests with aspergillus antigens.

Differential diagnosis of pulmonary aspergillosis is carried out with inflammatory diseases respiratory tract of viral or bacterial etiology, sarcoidosis, candidiasis, pulmonary tuberculosis,

With aspergilloma of the lungs, surgical tactics are indicated - economical resection of the lung or lobectomy. In the process of treating any form of aspergillosis, it is necessary to conduct stimulating and immunocorrective therapy.

Forecast and prevention of aspergillosis

The most favorable course is observed with aspergillosis of the skin and mucous membranes. Mortality from pulmonary forms of mycosis is 20-35%, and in people with immunodeficiency - up to 50%. The septic form of aspergillosis has a poor prognosis. Measures to prevent infection with aspergillosis include measures to improve sanitary and hygienic conditions: dust control at work, employees of mills, granaries, vegetable stores, weaving enterprises wearing personal protective equipment (respirators), improving ventilation of workshops and warehouses, regular mycological examination of persons from risk groups.

Everyone at least once in his life met black mold in basements, damp corners of the room, on walls, potted plants and old books. The scientific name of this fungus is Aspergillus niger. With a reduced immunity of a person or animal, mold enters the body through the air and can lead to serious illness. In this article, we will tell you what this fungus is and how to prevent infection.

Aspergillus niger are fungi that can take root and grow into a colony at temperatures above 40⁰С. They occupy a large area in very short term - up to 3 days. The fungus got its name due to the characteristic dark gray and black color, which indicates the maturation of conidia. They are microscopic formations at the top of the conidial head of the fungus.

Morphologically, Aspergillus niger is represented by several strains that live in damp rooms, food products, and even the human body. Thus, the fungus is ubiquitous, except for vacuum and in conditions of complete sterility. Aspergillus particles separated from the mycelium are in open space. Reproduction of the fungus occurs when the spore attaches and goes unnoticed. Its structure consists of 2 thread-like bodies: one is a vegetative formation, and the second gives life to new spores when ripe.

Favorable factors that contribute to the development of a fungal infection include:

• lack of ventilation in the premises;
• stuffy and poorly ventilated rooms;
• sharp jumps in air temperature;
• the presence of condensate in the premises;
• insufficient tightness of food packaging.

Application in industry

Beginning in the 1920s, strains of Aspergillus niger began to be used to make citric acid from sugary substances. During the production of the product in the reactor, the volume of which is 300 cubic meters, 15 tons of aspergillus cell mass is formed. This biomass is then burned.

From the cell wall of fungi, glucose oxidase is extracted, which is used in test strips to determine blood sugar levels. Hydrogen peroxide, being a product of the reaction of D-glucose with glucose oxidase, oxidizes the substance, changing the color.

Aspergillus niger enzymes cellulase, pectinase and hemicellulase are widely used in the production of fruit juices and purees. This increases the efficiency of raw material processing. They are also used in pulp and paper mills and in the manufacture of detergents.

Aspergillus niger is a source of the enzyme glucoamylase, which breaks down starch. It is used in the production of maltose and maltose syrups. Derived from a fungus, xylanase is used by bakers to improve the evenness and porosity of baked goods..

Entry into the human body

The most common way Aspergillus black enters the human body is inhalation of air with spores. Most often, people whose occupation is associated with infection with a fungal infection are:

• with grain processing;
• with baking craft;
• with spinning;
• with cheese making.

Often infection with the fungus Aspergillus niger occurs in the following ways:

• through food;
• through the mucous membrane;
• through microcracks and wounds on the skin.

Long-term treatment with antibiotics and radiation therapy increases the chances of fungus penetration.

Symptoms and testing

Despite being the most common pathogen of its kind, Aspergillus niger also infects many organs.

After a while, the person develops a violent cough with dirty white sputum. Sometimes there are blood clots in it. Also, the patient has signs of intoxication of the body: lethargy, fatigue, decreased performance, weight loss. Ineffective treatment leads to the appearance of pulmonary mycosis. This condition is accompanied by a severe wet cough, fever, chest pain and shortness of breath. Sputum examination revealed Aspergillus spores.

When Aspergillus niger VKPM F1331 gets into eyeballs symptoms of blepharitis, conjunctivitis and dacryocystitis are observed. Ineffective therapy causes partial or complete loss of vision.

If an infection occurs skin hands and nails, symptoms such as peeling, itching, unpleasant odor, infiltration are observed. With inactivity, the color of the nail gradually changes from yellow-brown to greenish-brown. In addition, the nail plate thickens and its structure becomes porous.
Diagnosis of the disease includes instrumental (CT, X-ray) and laboratory methods (sputum, urine, serological tests). Once the diagnosis is confirmed, treatment should be started immediately.

How to remove Aspergillus niger

To get rid of the fungus, it is necessary to approach its treatment in a complex manner. Often a specialist prescribes a number of medicines:

• Mycotic drugs against aspergillosis niger - Amphotericin B, Voriconazole, Flucytosine and Itraconazole. The funds are issued in different forms(inhalation, orally or intravenously).
• Topical medicines - antifungal ointments and antiseptics. Mainly used for cutaneous aspergillosis.

In advanced form, pulmonary aspergillosis is fatal in 50% of cases.

Room processing

As a rule, black mold is typical for old damp and corner apartments in multi-storey buildings. Therefore, the inspection of such premises plays an important role in the prevention of the disease.

The fungus Aspergillus niger lives behind wallpaper, in ventilation and at tile joints. To avoid contracting aspergillosis, follow these rules:

• Conduct a general cleaning of the bathroom with antibacterial agents at least once every 3 months.
• Do not allow dampness in the basement, as well as deposits of rotting vegetables.
• Do not install wooden shelves and ceilings in damp houses.
• If black mold appears on the wall, you need to think about its integrity and insulation.

However, this is not the only fungus that a person encounters every day. How to identify and not get infected with it, read in our separate material.