Generality
Potentially pathogenic fungi are organisms capable of causing disease in humans or other living organisms.
Infections induced by potentially pathogenic fungi are known as mycoses. There are 5 types of mycoses: superficial mycoses, cutaneous mycoses, subcutaneous mycoses, systemic mycoses due to primary pathogens and systemic mycoses due to opportunistic pathogens.
Among the fungi with pathogenic properties, the note stand out Candida albicans (which causes candidiasis or candidiasis), the "Aspergillus fumigatus (which causes aspergillosis), the Cryptococcus neoformans (which causes cryptococcosis), the "Histoplasma capsulatum (which causes histoplasmosis), the Pneumocystis carinii (which causes pneumocystosis) etc.
What are mushrooms?
Fungi, intended as potentially pathogenic fungi, are eukaryotic organisms capable of causing disease in humans or other living organisms.
Fungi with pathogenic properties are divided into two main categories: yeasts (singular yeast) and molds (singular mold). Yeasts are microorganisms, as they are unicellular, that is, composed of only one cell; molds, on the other hand, are organisms made up of more than one cell, ie they are multicellular.
In fact, it should be noted right away that the yeast / mold distinction is not always so clear-cut. In fact, depending on the environmental conditions in which they live, some pathogenic fungi can behave like a generic yeast or a generic mold; mushrooms with such abilities are called diformics.
Potentially pathogenic fungi include saprophytic organisms (ie which feed on dead organic matter) and parasitic organisms (ie which live at the expense of other organisms).
WHAT IS THE STUDY OF PATHOGENIC MUSHROOMS NAME FOR HUMAN BEING?
The branch of medicine that deals with the study of pathogenic fungi is called medical mycology. Mycology is the term that indicates the discipline of biology that studies fungi in general.
WHAT IS THE NAME OF DISEASES CAUSED BY PATHOGENIC FUNGI?
Diseases caused by potentially pathogenic fungi are infectious diseases or infections.
In specialist jargon, infections with potentially pathogenic fungi are called mycosis.
Since there are so many types of pathogenic fungi, there are also numerous types of mycosis.
To simplify the study of the enormous variety of mycoses, doctors thought of classifying the infectious diseases in question according to the site of infection. According to the site of infection, mycoses are divided into 5 large groups: superficial mycoses, cutaneous mycoses, subcutaneous mycoses (or subcutaneous mycoses), systemic mycoses due to primary pathogens and systemic mycoses due to opportunistic pathogens.
Biology
After numerous debates in this regard, the scientific community has decided that fungi represent a kingdom in their own right, therefore different from the kingdom of plants, the kingdom of animals, the kingdom of bacteria, etc.
CELLULAR CHARACTERISTICS OF MUSHROOMS
Like the cells of any eukaryotic organism, fungal cells contain an organized nucleus enclosed within its own specialized compartment, have a DNA divided into chromosomes, are equipped with organelles and possess an articulated system of membranes within the cytoplasm. .
Fungi have some cellular peculiarities similar to those of animals, plants or bacteria. In other words, they are, in some respects, comparable to animals, while, in other respects, they are similar to plants or bacteria. Taken together, all of these similarities mean that fungi are a type of organism in their own right, with animal, plant and bacterial characteristics.
To better understand:
- Similar to animals, fungal cells possess mitochondria and not chloroplasts (typical of plants). Furthermore, they are heterotrophic. A heterotrophic organism is a living being unable to synthesize the organic substances, necessary for life, from inorganic substances, as plants do (autotrophic organisms); lacking this potential, the only way they can survive is to feed on the organic substances produced by other organisms.
- Similarly to plants, fungal cells possess a cell wall, around the cytoplasmic membrane, and the vacuole.
- Similar to bacteria, the fungal cells are capable of synthesizing the amino acid L-lysine.
Clearly, if fungi have mitochondria, like animals, they cannot be plants or bacteria; but they cannot be animals either, because their cells are surrounded by a cell wall, contain a vacuole and have the ability to synthesize the amino acid L-lysine (which are peculiarities of plants and bacteria).
Is the cell wall of fungi like that of plants?
Structurally, the cell wall of fungi is different from that of plants. In fact, unlike the cell wall of plants, it also contains a substance known as chitin.
REPRODUCTION OF PATHOGENIC MUSHROOMS
Pathogenic fungi are characterized by three modes of reproduction: binary cleavage, budding and sporogenesis.
Binary cleavage and budding are typical of yeasts, while sporogenesis characterizes the reproductive processes of molds.
WHAT ARE PHAS?
Hearing the descriptions of mushrooms or reading something about them, many readers will surely have come across the term ifa (plural hypha).
Briefly, the hyphae are the filamentous structures forming the so-called mycelium (ie the vegetative body of fungi) and which characterize the vegetative growth process, typical of fungi.
Unicellular or multicellular, hyphae contain a large number of organic molecules, including proteins, lipids, etc.
Among the pathogenic fungi, the only ones not exploiting the hyphae for vegetative growth are yeasts
Clinical aspects
Rarely, pathogenic fungi infect healthy people. As a rule, in fact, they attack more easily individuals who:
- They suffer from diabetes. The high concentration of glucose in the blood (hyperglycemia), typical of diabetes, favors the proliferation of some particular fungi that populate certain anatomical areas of the human body and which, in normal conditions (ie absence of diabetes), are completely harmless.
- They have been subjected to inadequate antibiotic therapy or for too long periods. The prolonged and / or inadequate intake of antibiotics destroys the intestinal bacterial flora. The latter has the task of controlling the proliferation of pathogenic fungi, physiologically present inside the human intestine. The compromise of the bacterial flora makes it easier for the potentially pathogenic fungi to spread to the human being concerned.
- They have an ineffective immune system. The immune system is the defensive barrier of an organism against threats coming from the external environment, such as viruses, bacteria, fungi, etc., but also from the internal environment, such as cancer cells (the so-called "crazy cells" ) or malfunctioning.
To affect the efficiency of the human immune system can be morbid conditions, such as AIDS (ie HIV infection) or the intake of certain drugs, such as corticosteroids, chemotherapy or immunosuppressants.
Furthermore, it should be remembered that a weak immune system is typically present in very young subjects (because it is not yet fully developed) and in very elderly subjects (because it suffers a physiological decline in efficacy).
Examples
This chapter describes the main potentially pathogenic fungi, subdividing them, for easier consultation by the reader, according to the site of infection.
SUPERFICIAL MYCOSES
Superficial mycoses affect the outermost layers of the skin, hair and / or skin hair. They have the particularity of not evoking any immune response.
The main pathogenic fungi that cause superficial mycosis are:
- Piedraia hortae. It is responsible for an infection known as black piedra. Black piedra is a disease of the scalp, which involves the formation of brown / black nodules on the hair shaft. Piedraia hortae they are not very common in the world, except in the tropical areas of Africa and South America. To favor infectious diseases from Piedraia hortae it is poor personal hygiene.
- The fungal pathogens known as Trichosporon. The mushrooms Trichosporon, in particular Trichosporon asahii, Trichosporon beigeii, Trichosporon inkin And Trichosporon mucoides, are responsible for an infection known as white piedra. White piedra involves the formation of numerous small, round, white nodules in the hair and in the skin of the groin and armpits; sometimes, it also affects the outermost layers of the skin.
Infections from Trichosporon they are particularly widespread in tropical and subtropical geographical areas. Poor personal hygiene favors its spread. - Malassezia furfur. It is responsible for an "infection called pityriasis versicolor, which causes" hyperpigmentation or "hypopigmentation of the skin.
Infectious diseases from Malassezia furfur they mainly affect the anatomical area of the chest, neck, back and shoulders.
Heat, humidity, poor personal hygiene and an increase in sebaceous secretions are among the main factors favoring infections from Malassezia furfur. - Hortae werneckii (or Phaeoannellomyces). It is a yeast. It is responsible for an infection known as tinea nigra. Tinea nigra is responsible for skin patches of varying size, irregular, often isolated, brown or black, on the palms of the hands and soles of the feet.
Infectious diseases from Hortae werneckii they are particularly widespread in Central America, South America, Africa and Asia; they mainly affect children, adolescents and young adults.
CUTANEOUS MYCOSES
Also known as ringworm, cutaneous mycoses affect the keratinized layers of the epidermis, hair, hair and / or nails (N.B: keratinized means that they contain the keratin protein).
Unlike superficial mycoses, cutaneous mycoses evoke an immune response and are responsible for a process of degradation in the epidermal layers containing keratin; this degradation process induces irritation, inflammation and, in some cases, even allergic reactions.
Called dermatophytes or dermatomycetes, the fungi responsible for cutaneous mycoses are mostly filamentous fungi with the particularity of reproducing through spores.
In nature, there are three genera of dermatophytes: the genus Microsporum, the genre Trichophyton and gender Epidermophyton.
- The genre Microsporum includes unicellular and multicellular fungi. The best known species of the genus Microsporum are: Microsporum audouinii, Microsporum canis And Microsporum gypseum.
All three species can cause ringworm episodes on the scalp and the whole body, but, while Microsporum audouinii And Microsporum gypseum specifically affect the human being, Microsporum canis affects dogs, cats and livestock with greater preference. Humans infected with Microsporum canis they are generally people who live in close contact with infected animals. - The genre Trichophyton includes unicellular and multicellular fungi. The best known species of the genus Trichophyton I'm: Trichophyton rubrum, Trichophyton mentagrophyes And Trichophyton verrucosum.
Trichophyton rubrum causes ringworm in the feet, hands, groin and / or nails. Readers are reminded that nail fungus is better known as onychomycosis.
Trichophyton mentagrophyes it is the infectious agent responsible for the condition known as athlete's foot. Athlete's foot is a fungal infection that affects the areas between the toes and causes: red itchy skin, skin thickening, skin peeling, blistering, cracking of the skin, smelly feet and thicker nails .
In the end, Trichophyton verrucosum it is responsible for cutaneous mycosis especially among horses, donkeys, dogs and sheep; only in rare cases it also infects the human being. In the latter, it affects the scalp, causing alopecia or baldness. Typically, humans who contract infections from Trichophyton verrucosum they live in close contact with the aforementioned categories of animals. - The most important species of the genus Epidermophyton è Epidermophyton floccosum. The latter can cause ringworm in the feet, legs, arms and nails (onychomycosis).
