Aspergillus life cycle. Aspergillus niger - what is it? Morphology, treatment

Growth and distribution

Aspergillus is classified as a deuteromycete fungus that does not have a sexual stage of development. With the advent of DNA analysis data, it has become more likely that all members of the genus Aspergillus are closely related to the Ascomycetes, and should be considered members of the Ascomycetes. Representatives of the genus have the ability to grow wherever there is a high osmotic concentration (strong solutions of sugar, salt, etc.), and are very resistant to environmental influences. Aspergillus species are highly aerobic and can be found in almost all oxygen-rich environments, where they typically grow as a mold on the surface of the substrate as a consequence of high oxygen enrichment. Generally, fungi grow on carbon rich substrates such as monosaccharides (eg glucose) and polysaccharides (eg amylose). Aspergillus species are a common contaminant of starchy foods (such as bread and potatoes) and grow in or on the surface of many plants and trees.

In addition to growth on carbon sources, many species of the genus Aspergillus exhibit oligotrophy, that is, the ability to grow in nutrient-poor environments, or in conditions of complete absence of key nutrients. The main example of this is A.niger- it can be found growing on damp walls as a major component of downy mildew (English).

Significance for a person

Aspergillus species are medically and commercially important. Some species can infect humans and other animals. Some infections found in animals have been studied for years; while other species found in animals have been described as new and specific to the disease under study. Others were known as names already in use for organisms such as saprophytes. Over 60 Aspergillus species are significant medical pathogens. There are a number of human diseases such as pinna ear infection, skin lesions, and ulcerations classified as mycetomas.

Other species are important in industry in the manufacture of enzyme preparations. For example, spirits such as Japanese sake are preferred to be made with rice or other starchy ingredients (such as cassava) instead of grapes or malted barley. Typical microorganisms used to produce alcohol, such as yeasts of the genus Saccharomycetes, cannot ferment starch. Therefore, mold is used to break down starch into simpler sugars. koji(For example, Aspergillus oryzae). Aspergillus oryzae, Aspergillus sojae, Aspergillus tamari used to make soy sauce, as well as various types of soy paste - miso, doenjang and others.

Aspergillus fungi are widely used to determine the content of inorganic cations and anions. Representatives of the genus Aspergillus are also sources of natural substances that can be used in the manufacture of medicines for the treatment of various human diseases. Perhaps the most widely used Aspergillus niger, as the main source of citric acid. This organism provides 99% of the world production of citric acid - more than 1.4 million tons per year. A.niger also often used to produce true (native) and foreign enzymes, including glucose oxidase and egg protein lysozyme. In such cases, the culture is rarely grown on a solid substrate (although this practice is still common in Japan). More often it is grown as a deep culture in a bioreactor. With this method, you can tightly control important parameters and achieve maximum productivity. This process also greatly facilitates the separation of the target chemical or enzyme from the culture medium and is therefore much more cost effective.

Research

sexual reproduction

Of the 250 Aspergillus species, about 64% have no known sexual stage. However, it is becoming increasingly clear that many of these species likely have an as yet unidentified sexual stage. Sexual reproduction in fungi occurs in two fundamentally different ways. This is outcrossing (cross-crossing) in heterothallomas. (English) fungi, during which two different individuals exchange nuclei, and self-fertilization in homothalloma (English) fungi, where both nuclei come from the same individual. In recent years, sexual cycles have been discovered in a large number of species previously considered asexual. These discoveries reflect the focus of current empirical research on species specifically related to humans. Some species for which sexual reproduction has recently been confirmed are described below.

These results from studies of Aspergillus species are consistent with data accumulated from studies of other eukaryotic species, and indicate the likely presence of sexual behavior in a common ancestor of all eukaryotes. A. nidulans- homothallomic fungus capable of self-fertilization. Self-fertilization involves the activation of the same sexual reproduction pathways as in outcrossing species. This does not mean that self-fertilization goes through the necessary stages characteristic of outcrossing, but that instead, activation of these mechanisms is required within a single representative of the species. The vast majority of species Aspergillus, demonstrating sexual cycles, are homothallomic in nature (self-fertilizing). This observation suggests that, in general, species Aspergillus can maintain sexual reproduction, even though the level of genetic diversity of the offspring as a result of homothallomic self-fertilization is low. A. fumigatus- homothallomic (reproducing by outcrossing) fungus, which occurs in areas that differ significantly in climate and environmental conditions. This species also exhibits a low degree of variability both within geographic regions and across the planet, again suggesting that sexual reproduction - in this case reproduction by outcrossing - can persist even when the degree of genetic variability is low.

Genomics

Simultaneous publication of three manuscripts on the topic of the genome Aspergillus in the journal Nature in December 2005 made this genus the leading subject for research in comparative genomics among micellar (filamentous) fungi. Like most genomic projects, these efforts have been undertaken by major sequencing centers in collaboration with the relevant scientific communities. For example, the Institute for Genome Research (TIGR) () has worked with the research community A. fumigatus. A. nidulans was sequenced at the Eli and Edith L. Brad Institute () A. oryzae was sequenced in Japan at the National Institute of Advanced Industry and Technology. The Joint Genome Institute () of the Ministry of Energy published sequenced data on the genome of the strain A.niger used for the production of citric acid. TIGR, now renamed the Venter Institute (), currently leads the Species Genome Project A. flavus. Sizes of sequenced genomes of species Aspergillus fluctuate within 29.3 MB A. fumigatus and 37.1 MB A. oryzae, while the number of predicted genes varies from ~9926 y A. fumigatus up to ~12.071 y A. oryzae. Genome size in an enzyme-producing strain A.niger medium size and is 33.9 MB.

pathogens

Some species of aspergillus cause serious illness in humans and animals. The most frequently pathogenic species are A. fumigatus And A. flavus that produce aflatoxins, which are both toxins and hepatocarcinogens. They can contaminate food such as nuts, seeds and grains. Common causative agents of various allergic diseases are species A. fumigatus And Aspergillus clavatus (English) . Other species are important as crop pathogens. Representatives of the species Aspergillus cause disease in many cereals, especially corn; some synthesize mycotoxins, including aflatoxin.

Aspergillosis

• Allergic bronchopulmonary aspergillosis affecting patients with respiratory infections such as bronchial asthma, cystic fibrosis, and sinusitis
• Acute invasive aspergillosis, a form of aspergillosis in which fungi grow into surrounding tissues, occurs more frequently in people with a weakened immune system, such as those with AIDS or chemotherapy.
• Disseminated invasive aspergillosis is an infection that has spread widely in the body.
• Aspergilloma is a spherical fungal formation that can form in the sinuses and cavities, for example, in the lungs.

Most often, the fungus enters through the respiratory tract and mouth, and can affect both the respiratory system, and the central nervous system, digestive tract, skin, sensory organs, and reproductive system. Aspergillus meningitis or encephalitis in most cases ends in death. Aspergillus fungal infections of the spleen, kidneys, and bones also occur, but for the most part they are caused by secondary infection. Respiratory aspergillosis is often diagnosed in birds and certain species are known. aspergillus that infect insects.

see also

Notes

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2. lenta.ru - Mold fungi were able to have sex, (eng.)
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6. POLIT.RU \ RESEARCH \ Many-sided mold ("Science and Life"//2009. No. 10)
7. Aspergillus niger culture - citric acid producer Archived March 5, 2011.
8. Wortman J. R. , Gilsenan J. M. , Joardar V. , Deegan J. , Clutterbuck J. , Andersen M. R. , Archer D. , Bencina M. , Braus G. , Coutinho P. , von Döhren H. , Doonan J. , Driessen A. J. , Durek P. , Espeso E. , Fekete E. , Flipphi M. , Estrada C. G. , Geysens S. , Goldman G. , de Groot P. W. , Hansen K. , Harris S. D. , Heinekamp T. , Helmstaedt K. , Henrissat B. , Hofmann G. , Homan T. , Horio T. , Horiuchi H. , James S. , Jones M. , Karaffa L. , Karányi Z. , Kato M. , Keller N. , Kelly D. E. , Kiel J. A. , Kim J. M. , van der Klei I. J. , Klis F. M. , Kovalchuk A. , Krasevec N. , Kubicek C. P. , Liu B. , Maccabe A. , Meyer V. , Mirabito P. , Miskei M. , Mos M. , Mullins J. , Nelson D. R. , Nielsen J . , Oakley B. R. , Osmani S. A. , Pakula T. , Paszewski A. , Paulsen I. , Pilsyk S. , Pócsi I. , Punt P. J. , Ram A. F. , Ren Q. , Robellet X. , Robson G. , Seiboth B. , van Solingen P. , Specht T. , Sun J. , Taheri-Talesh N. , Takeshita N. , Ussery D. , vanKuyk PA , Visser H. , van de Vondervoort P. J. , de Vries R. P. , Walton J. , Xiang X. , Xiong Y. , Zeng A. P. , Brandt B. W. , Cornell M. J. , van den Hondel C. A. , Visser J. , Oliver S. G. , Turner G. The 2008 update of the Aspergillus nidulans genome annotation: a community effort. (English) // Fungal genetics and biology: FG & B. - 2009. - Vol. 46 Suppl 1. - P. 2-13. - DOI:10.1016/j.fgb.2008.12.003 . - PMID 19146970 .[to correct]
9. Descriptions - Aspergillus Comparative (indefinite) . Broad Institute. Retrieved October 15, 2009. Archived from the original on November 22, 2009.
10. Dyer P. S. , O "Gorman C. M. A fungal sexual revolution: Aspergillus and Penicillium show the way. (English) // Current opinion in microbiology. - 2011. - Vol. 14, no. 6. - P. 649-654. - DOI:10.1016/j.mib.2011.10.001 . - PMID 22032932 .[to correct]
11. O "Gorman C. M. , Fuller H. , Dyer P. S. Discovery of a sexual cycle in the opportunistic fungal pathogen Aspergillus fumigatus. (English) // Nature. - 2009. - Vol. 457, no. 7228 . - P. 471-474. - DOI:10.1038/nature07528. - PMID 19043401 .[to correct]
12. Horn BW, Moore GG, Carbone I (2009). "Sexual reproduction in Aspergillus flavus". mycology. 101 (3): 423-9. DOI:10.3852/09-011. PMID.
13. Swilaiman SS, O "Gorman CM, Balajee SA, Dyer PS (July 2013). “Discovery of a sexual cycle in Aspergillus lentulus, a close relative of A. fumigatus” . eukaryotic cell. 12 (7): 962-9. DOI:10.1128/EC.00040-13. PMC. PMID.
14. Arabatzis M, Velegraki A (2013). “Sexual reproduction in the opportunistic human pathogen Aspergillus terreus” . mycology. 105 (1): 71-9. DOI:10.3852/11-426. PMID.
15. Malik SB, Pightling AW, Stefaniak LM, Schurko AM, Logsdon JM (2008). “An expanded inventory of conserved meiotic genes provides evidence for sex in Trichomonas vaginalis” . PLOS ONE. 3 (8): e2879.

- 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. In the 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 stored food, agricultural and indoor plants, 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 the incidence of aspergillosis include immunodeficiencies of any origin, chronic diseases of the 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. The initial stages of 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 of the 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.

The mold that has appeared in the house can not only spoil the appearance of the walls, covering them with an ugly black coating, but also seriously undermine human health. Its spores can provoke the development of benign and malignant tumors, allergies, dermatitis and other dangerous pathologies. Therefore, it is important to know why mold is dangerous, how to get rid of it and prevent its occurrence.

Varieties

Black mold plaque is a colony of microscopic fungi. Most often these are the following types.

Aspergillus niger (Aspergillus black)

This saprophytic fungus develops on the surface of damp walls and ceilings, on sheets of old books, in pots of indoor plants, on tile joints in rooms with high humidity (bathrooms, kitchens, baths, swimming pools), in washing machines, air conditioners, air humidifiers.

The spores of this fungus are easily spread throughout the room with the help of air movement, enter the human body through the respiratory tract, and settle on food and household items. They cause:

• rhinitis;
• bronchial asthma;
• pneumonia;
• myocarditis;
• meningitis;
• the formation of papillomas and even cancer cells.

When a large number of spores are inhaled, a person may develop intoxication phenomena, which, in the case of a weakened immune system, can be fatal.

A specific disease caused by the fungus Aspergillus niger is pulmonary aspergilloma. Penetrating through the nasopharynx into the bronchi, bronchioles and alveoli, the spores begin to actively develop, releasing the strongest toxins, leading to the formation of necrotic foci. Gradually, the parenchymal tissue ceases to perform its function, asphyxia and death occur.

Aspergillus fumigatus (Smoky Aspergillus)

More often it affects the fruits of vegetables and fruits that have mechanical damage. If the grain was affected by this type of fungus, then a fluffy black coating very quickly forms on bakery products. The danger lies in the fact that the toxin it releases is a strong allergen that causes the destruction of red blood cells and suppresses the production of immune cells.

Alternaria tenuis (Alternaria alternata)

It is a fungus that forms black colonies on walls, food and soil. The toxin released during its vital activity can cause attacks of bronchial asthma and dermatitis.

What encourages fungus to grow

Understanding how dangerous black mold is, it is necessary to take all measures to prevent its appearance in the house. Therefore, it is worth knowing the ways in which pathogenic fungi enter the human home.

Optimal conditions are temperature +18…+25°C with humidity over 70%. Poor ventilation also contributes to this. These are factors that can be eliminated on their own, avoiding large material costs. But there are reasons for the appearance of mold, which some people do not even know about. And they are associated with the use of new building and finishing materials, as well as non-compliance with the rules for their installation.

Plastic windows and doors

On the one hand, this very convenient invention makes it possible to avoid heat losses in the building, minimizes installation, maintenance and restoration costs, and ensures a certain safety of residents. But, on the other hand, their improper operation can lead to the appearance of spores of pathogenic fungi.

The fact is that such windows disrupt the air circulation in the room, provoking the formation of high humidity. This can be avoided by regular ventilation, which should be mandatory even in the cold season.

The second reason may be the formation of condensation on the glass surface. This is due to the incorrect selection of the number of glasses or air chambers in a double-glazed window, with poor product quality or illiterate installation.

Application of drywall

This building material is very convenient for leveling walls, ceilings and erecting partitions. Affordability and ease of use make it quite popular with builders and people involved in repairs. But at the same time, many do not take into account the ability of this material to absorb moisture well and keep it inside for a long time.

Therefore, all installation technologies and the drying time of the mixtures must be clearly observed. In such a room, microclimate parameters should be created that prevent the appearance of black mold.

If the building is expected to have an increased level of humidity, then antifungal components should be added to the solutions.

Poor ventilation

The layout of apartments and houses often does not provide for the presence of windows in the bathrooms, and natural exhaust ducts cannot cope with the large amount of moist air generated during the adoption of water procedures or drying clothes. In this case, it is advisable to install forced ventilation. It will quickly solve this problem and prevent the development of mold microflora, which, with humid warm air, quickly penetrates the human body, having a negative impact on its health.

Damp exterior walls and basements

Clogged drainpipes or their absence leads to frequent wetting of walls and corner parts of buildings. This can cause mold to appear on the facade of the building, which will eventually grow inside the premises. This may be due to the presence of cracks in the masonry.

Damp basements can also be breeding grounds for mold, whose spores can quickly spread through the ventilation system throughout the building.

Mold can get into the house with food or houseplants. Therefore, pieces of bread, cheese, cereals, vegetables and fruits affected by fungi must be carefully packed in a plastic bag and removed from the room. Eating such food can cause serious harm to health.

Control measures

Having realized how dangerous mold is to health, and finding it in your home, you should take urgent measures to eliminate it.

The most effective way is to treat the room with a UV lamp. Ultraviolet rays completely destroy fungal spores. For the period of turning on the device, all fresh flowers must be taken out of the room and pets must be removed. We must not forget about the aquarium with fish.

Other destruction methods include:

1. Removing the source of mold from the premises. It can be wallpaper, putty, affected textiles.
2. Adding antiseptics and special antifungal agents to building and finishing mixtures. Particular attention should be paid to grouting tile joints in the bathroom and kitchen.
3. Treatment of affected areas with industrial products, as well as vinegar, soda, bleach solution, hydrogen peroxide or borax.

Remember - it is impossible to leave lesions in an apartment or house untreated. The danger of mold has been proven, so you should not put your health and the health of your children at risk.

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 death.

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, and high humidity is a favorable condition for existence. 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 immunodeficient 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 of internal organs, mucous membranes and skin are described. 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. The last 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 shape;
4) skin form;
5) defeat of ENT organs;
6) damage to bones;
7) other more rare forms of aspergillosis (damage to the mucous membranes of the oral cavity, reproductive system, and others).

Bronchopulmonary form- the most common form of aspergillosis, characterized by symptoms of tracheitis, bronchitis or tracheobronchitis. Patients complain of weakness, the appearance of a cough with gray sputum, 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 is the 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: complete blood count: 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 times a 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.

In everyday life, a person often encounters 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, and some food products.

The spores of these fungi are constantly in the air, for a person with a strong immune system, they do not pose any 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, many types of this moldy fungus will be distinguished. 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, yeast dough, smoked meats, some types of cheeses, kvass, wines, beer, dried fruits from his diet. 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 type of fungus, they are not very significant, since any species prefers to settle in similar places in the home or in the external environment, they all 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 over 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.

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