Introduction to Mycology PDF

‫‪ Welcome to the country of Iran and the city‬‬ ‫‪of Arak‬‬ ‫مرحبا بكم في بلد إيران ومدينة أراك ‪‬‬ ‫به کشور ایران و شهر اراک خوش آمدید ‪‬‬ Medical Mycology Mojtaba Didedar – Fall 2023 Medical Mycology, Dept of Medical Mycology & Parasitology, Arak University of Medical...

‫‪ Welcome to the country of Iran and the city‬‬ ‫‪of Arak‬‬ ‫مرحبا بكم في بلد إيران ومدينة أراك ‪‬‬ ‫به کشور ایران و شهر اراک خوش آمدید ‪‬‬ Medical Mycology Mojtaba Didedar – Fall 2023 Medical Mycology, Dept of Medical Mycology & Parasitology, Arak University of Medical Sciences  About Me…. Dr. Mojtaba Didehdar  Ph.D. in Medical Mycology (Basic education in Laboratory Science)  Faculty member of Arak University of Medical Sciences (Associate Professor)  Work experience: about 15 years in the medical diagnosis laboratory  Technical Supervisor at the technical Mycology department of the specialized & super specialized clinical laboratory of Imam Reza Clinic, University of Medical Sciences in Arak. Mojtaba Didehdar 361-2422 )918( 98+ [email protected] c.ir General Information  Instructor: Dr. Mojtaba Didehdar  Course Title: Medical Mycology  Credit Hours: 2  Office: Dept of Medical Mycology and Parasitology, Arak University  Office Phone: +98 (86) 3417-3620  Office Hours: To be discussed  Email: [email protected], [email protected] Social Networks Mobile: +98 (918) 361-2422  M.Didehdar, Medical Mycology, Dept of Medical Mycology & Parasitology, Khomein University of Medical Sciences, Fall 2022 Course Description Requirements – Prerequisites Biochemistry A detailed description of general mycology would be presented along with the Fungal structure, Fungal Physiology including: the reproduction, nutrition and their metabolism. Superficial, cutaneous, subcutaneous and visceral fungal diseases and their epidemiology treatment would be introduced. The course would be presented along various case studies which helps understanding concepts. M.Didehdar, Medical Mycology, Dept of Medical Mycology & Parasitology, Khomein University of Medical Sciences, Fall 2022  Course Objectives By the end of the course, you should be able to do the following: Fungal structure and their Physiology Know fungal diseases and their epidemiology treatment Know how to discriminate between microscopy and macroscopic fungal. M.Didehdar, Medical Mycology, Dept of Medical Mycology & Parasitology, Khomein University of Medical Sciences, Fall 2022  Teaching Calendar  Time: 10:00 – 12:00 Saturday  Location for Theory Class : Arak University of Medical Sciences Location for Practical Class under Supervision Mr. Haji Hosseini: The first floor of the yellow wing. Dept of Medical Mycology and Parasitology, Arak University.  Activities: - Present new Material - Announce Reading and homework  Final Exam: To be announced. ‫دی‬ ‫آذر‬ ‫شه مهر آبان‬ ‫ریو‬ ‫ر‬ Sa Sat Sat Sat Sat t 30 2 19 7 9 26 16 M.Didehdar, Medical Mycology, Dept of Medical Mycology & Parasitology, Khomein University of Medical Sciences, Fall 2022  Main Text book Essentials Of Medical Mycology by James C. Gentles E. Glyn V. Evans Publisher : Edinburgh ; Churchill Livingstone, 1985 ISBN-10 : 0443025053 ISBN-13 : 978-0443025051 Henry's Clinical Diagnosis and Management by Laboratory Methods by Richard A. McPherson, Matthew R. Pincus Publisher : Elsevier; 24th edition (June 15, 2021) ISBN-10 : 0323673201 ISBN-13 : 978-0323673204 ‫کتاب قارچ شناسی پزشکی جامع‬ ‫ مسعود امامی‬،‫ امیر سیدعلی مهبد‬،‫فریده زینی‬ ‫ دانشگاه تهران‬:‫ناشر‬ 1391 ‫ اردیبهشت‬5 :‫تاریخ نشر‬ M.Didehdar, Medical Mycology, Dept of Medical Mycology & Parasitology, Khomein University of 8-5948-03-964-978 :‫شابک‬ Medical Sciences, Fall 2022  Assessment  Final, Classroom activity Theory 80 % Practical 20 % M.Didehdar, Medical Mycology, Dept of Medical Mycology & Parasitology, Khomein University of Medical Sciences, Fall 2022  General mycology M.Didehdar, Medical Mycology, Dept of Medical Mycology & Parasitology, Khomein University of Medical Sciences, Fall 2022.Introduction to Mycology  Over the course of time, more than 100,000 species of fungi have been recognized and described. However, fewer than 500 of these species have been associated with human disease. The remainders are only able to produce disease in hosts that are debilitated or immunocompromised.  What is mycology?  Mycology is the study of fungi. The disease caused by fungi is called MYCOSES.  What are fungi?  Eukaryotic, spore-bearing, heterotrophic organisms that produce extracellular enzymes and absorb their nutrition.  By the Development of the electron microscope in 1995s, Fundamental differences between the bacteria and fungus were discovered:  Although in many ways fungi resemble bacteria (neither has chlorophyll), they are unlike bacteria in:  Composition of the cell walls.  Reproducing through sporulation or spore formation.  So it was classified again into 5 Kingdoms:  Bacteria.  Protista.  Animalia  Fungi  Plant 001  Comparison of fungi and bacteria feature fungi bacteria diameter 4um 1um nucleus Eukaryotic Prokaryotic cytoplasm Mitochondria and Golgi Mitochondria and apparatus , endoplasmic endoplasmic reticulum reticulum present absent Cell membrane Sterols present Sterols absent Cell wall Chitin Peptidoglycan, phospholipid spores Sexual and asexual spores for spores for survival, not for reproduction reproduction metabolism Require organic carbon; no May do not require organic obligate anaerobes carbon; many obligate anaerobes  NUTRITIONAL ADAPTATIONS OF FUNGI Fungi absorb their food, rather than ingesting it. - Fungi grow better at a pH of 5, which is too acidic for most bacteria. - Almost all molds are aerobic. Most yeasts are facultative anaerobes. - Fungi are more resistant to high osmotic pressure than bacteria. - Fungi can grow on substances with very low moisture. - Fungi require less nitrogen than bacteria to grow. - Fungi can break down complex carbohydrates (wood, paper), that most bacteria cannot. 002 General information's about FUNGI:  Fungi are not plants or animals, they form a separate group of higher organisms, distinct from both plants and animals, which differ from other groups of organisms in several major respects: First:  Fungal cells are encased within a rigid cell wall, mostly composed of chitin and glucan. These features contrast with animals, which have no cell walls, and plants, which have cellulose as the major cell wall component.  Chitin exist in the body of crustaceans such as crabs Cell walls contain chitin  Second:  Fungi are heterotrophic. This means that they are lacking in chlorophyll and cannot make their organic food as plants can, through photosynthesis. Fungi live embedded in a food source or medium, and obtain their nourishment by secreting enzymes for external digestion and by absorbing the nutrients that are released from the medium. Some live on humans e.g. the cause ringworm infections. Some live on insects, or plants.  Third:  Fungi are simpler in structure than plants or animals. There is no division of cells into organs or tissues.  :The basic structure of the fungi  The basic structural unit of fungi is either a chain of tubular, filament-like cells, termed a hypha or hyphae (plural) or an independent single cell.  The living body of a fungus is called a mycelium which is made up of a branching network of filaments known as hyphae.  Fungal cell differentiation is no less complicated than is found in plants or animals, but it is different. Many fungal pathogens of humans and animals change their growth form during the process of tissue invasion. These dimorphic pathogens usually change from a multicellular hyphal form in the natural environment to a budding, single-celled form in tissue.  In most multicellular fungi the vegetative stage consists of a mass of branching hyphae, termed a mycelium. Each individual hypha has a rigid cell wall  They are filamentous, gram positive and bear fruiting bodies called spores.  Can exist as single cells or chains of cells. Structure of fungi Structure and Function of Fungi Mycelium: Large, Visible Mass of Hyphae In the last 20 years extraordinary changes in fungal infection pattern!!  New pathogens have emerged  Increasing international travel  use wrongly of antimicrobial agents  Nutrient (mushroom)  Alcohol product (saccharomyces & penicillium roquefortii)  Product of metabolites (glycerol, manitol)  Preserver of foods( pullulan) Some basic terms:  Fungi (fungus)  Hyphae (hypha) = cellular thread  Septate = hyphae with cross walls  non-septate = hyphae without cross walls  Mycelium = complex of hyphae  The term mould is generally used to describe a fungus which produces hyphae.  The term yeast is generally used to describe a fungus which reproduces by budding. Morphology:  Filamentous (mould).  Yeast  Dimorphic 1- Yeast  Round, oval or elongated unicellular cells.  3-15 µm  Few capsulated  Reproduction – Sexual. – Asexual : by budding (blastoconidia or blastospores) – May give arise to pseudohyphae  Examples of pathogenic yeast:  Candida albicans  Unicellular fungi (smooth, soft, compact) Unicellular fungi Unicellular fungi  2- Filamentous fungi: – Multicellular – Form branching filamentous called hyphae – Hyphae form mycelium – Hyphae may be septate of aseptate – Reproduction: – Asexual: by Conidia and spore – Sexual.  Examples of pathogenic moulds  Dermatophytes  Multicellular fungi ( floc, villiform, dusty ) Multicellular fungi Hypha spor e  3- Dimorphic fungi:  Dimorphism this term is used to describe a fungus which occurs in two different forms (temperature and place), for example, some pathogenic fungi are filamentous in culture and yeast-like in infected tissues.  37°C yeast  20 – 30° C moulds.  Examples: – Paracoccidioides brasiliensis  Aseptate hypha, Septate hypha a.k.a. coenocytic See Fig. 31.3  Ecology and Nutrition  Although often inconspicuous, fungi occur in every environment on Earth and play very important roles in most ecosystems. Along with bacteria, fungi are the major decomposers in most terrestrial (and some aquatic) ecosystems, and therefore play a critical role in biogeochemical cycles and in many food webs. As decomposers, they play an essential role in nutrient cycling, especially as :  symbionts (relationships with organisms can be mutualistic e.g lichens and mycorrhizas or antagonistic in nature, or in the case of commensal fungi are of no apparent benefit or damage to the host e.g. parasitic fungi) *parasitic stage (necrotrophic or biotrophic) common called Pathogen e.g. rust, smut, powdry mildew, vascular wilt, downy mildew, Pneumocystis In biologic control nematophagous, entemopathogens *opportunistic stage  saprotrophs, degrading organic matter to inorganic molecules, which can then re-enter anabolic metabolic pathways in plants or other organisms.(biodegradation or biodeterioration)  Saprophytic fungi are fungi that are not pathogenic to humans in their natural state, but are pathogenic in patients with immune system defects.  Parasitic fungi are pathogenic both in natural maples and in immunocompromised individuals.  Reproduction 1) Spore : Fungal spores are formed from aerial hyphae ,motile and are used for both sexual and asexual reproduction. 2) Conidia:  Asexual reproduction  Budding, fission  Spore : Unicellular or multicellular spore that is not enclosed in a sac  Conidia: Unicellular or multicellular spore that is not enclosed in a sac.  Sporangiospores: Asexual spore formed within a sac  Chlamydioconidia: Thick-walled spore formed within a hyphal segment.  Arthroconidia Spore formation:  Most fungi reproduce by forming spores. When the spores germinate, they send out tube-like projections, called germ tubes, which lead to the formation of branching tube-like structures, called hyphae.. The spores may be produced in many different ways and their size, shape, colour, and manner of production are of value in identifying individual species. The principle types of spore are as follow: 1-Chlamydospore: a rest stage, forms when a cell swells up and develops a thick resistant wall. 2- Arthrospore: a spore forms by septation followed by fragmentation of hyphae. 3- Blastospore: a single vegetative cell of yeast which is produced by budding. 4- Conidium: a spore produced externally on a specialized hypae called conidiophore, the conidium (plural conidia) becomes detached when it mature. 5- Sporangiospore: a spore produced within a swollen spherical cell (sporangium) at the end of specialized hyphae called a sporangiophore. Yeast cell cycle  Yeast cells, which are simple, single celled eukaryotes, undergo cell division cycle like human cells. Yeast is a general term, like "animal", so that it covers organisms as diverse and humans and worms. Two types of yeast were used. The key is that yeast cells are (a) simple and (b) haploid, that is one copy of each chromosome. Budding Characteristics of Fungal Hyphae: Septate versus Coenocytic  Sexual reproduction – Ascospore – basidiospore – zygospore – oospore  Some fungi have no sexual reproduction (Imperfect fungi).  Sexual spores: Formed by the fusion of nuclei from two opposite mating strains of the same species. New organisms are different from both parents. Sexual reproduction in fungi Haploid spores may disperse long distances away from the fruiting body  Sexual reproduction - Sexual reproduction in fungi takes place in three stages: - Plasmogamy - Karyogamy - Meiosis  Hermaphroditic (Isogamous) Fungi: Male and female gametes are produced on the same mycelium. Homothallic Heterothallic  Sexual reproduction in fungi + fusion of compatible hyphae – (plasmogamy) hyphae (n) fused hyphae (n + n) dispersal of spores + zygote (2n) fusion of nuclei + (karyogamy) – – sexual spores (n) meiosis of zygotes (2n) “zygote-like” structures  Classification of Fungi  Domain Eukarya  Kingdom Fungi  Phylum -mycota  Class -mycetes  Order -ales  Family -aceae  Genus ----------  Species ---------- This classification applies to any organism  Kingdom:Fungi Phylum Subphylum 1)Zygomycota : zygomycotina Ascomycotina- Basidiomycotina : 2)Dikaryomycota Deutromycota: Class )3 Blastomycetes - Hyphomycetes - Coelomycetes -  Saprophytes Fungi Zycomycetes )1 Hyalin hyphomycetes)2 Phaeohyphomycetes)3  Zycomycetes Mucor )1 Rhizopus)2 005  Mucor - Colonies are very fast growing, cottony to fluffy, white to yellow, becoming dark-grey. -Vegetative myceliums are wide and without transverse walls. - Branched sporangiophores end in prominent members called columella. - Sporangium is placed around the columella, which is full of sporangiospores. - It causes mucoromycosis and is seen in the tissue in the form of wide hyphae without transverse walls(Septate).  Rhizopus - The colony grows fast and the color of the colony is gray and woolly. - The genus Rhizopus is characterised by the presence of stolons and pigmented rhizoids, the formation of sporangiophores, singly or in groups from nodes directly above the rhizoids, - Unbranched sporangiophores are located opposite the rhizoids. -The spherical sporangium is full of sporangiospores. - They cause copper mucoromycosis and are seen in the tissue like mucor.  Hyaline hyphomycetes Aspergillus )1 Penicillium )2 Scopulariopsis )3 Fusarium )4 Acremonium )5  Hyaline hyphomycetes Aspergillus )1 Penicillium )2 Scopulariopsis )3 Fusarium )4  Aspergillus - Colonies of aspergilli may be black, brown, yellow, red, white, green, or other colors depending on the species and the growth conditions. - The mycelium is well developed, branching, hyaline and septate. After a certain period of vegetative growth, under appropriate conditions, hyphal cells stop normal growth and begin conidiation by forming conidiophores. - - It is characterized by the formation of vesicles and swelling at the end of the conidiophore.  Aspergillus - - Depending on the species of Aspergillus, 1 or 2 rows of phialides are placed on the vesicle. - - Aspergillus species differ in the shape and size of conidia, conidiophorovesicles.They cause subcutaneous, skin and internal infections, nail and eye infectionsToxic products from its species lead to allergic reactions, such as aflatoxin produced by Aspergillus flavus, which is hepatotoxic and carcinogenic. - Important species: fumigatus, flavus, niger - They are seen in the tissue in the form of bifurcated hyphae.  Penicillium - The colony has fast growth and is powdery, smooth and bluish green. - Conidiophores are branched. - Terminal conidiophores that bear groups of 4–5 metulae supporting groups of 4–6 phialides. - Conidia have a brush-like state. - It is the cause of Penicilliosis and is used in the preparation of antibiotics.  Scopulariopsis - At first, the colony is white and waxy, then it turns brown and cream-colored and powdery. - Microscopically, the conidiogenous cells (annellides) are produced from unbranched or branched penicillate-like conidiophores. - Conidia are in chains with the youngest conidium at the base of the chain next to the tip of the annellide. - The conidia are thick-walled, round to lemon-shaped, rough to spiny with hyaline or brown cell walls.  Fusarium - The colony is first white and cottony and then turns pink or purple in color. - the conidiogenous cells are produced from unbranched or branched conidiophores. - Fusarium is the only saprophytic fungus that produces two types of conidia.  Fusarium  The production of both fusoid macroconidia (hyaline, multicellular clusters, macroconidia with foot cells at the base of the macroconidium) and microconidia (hyaline, unicellular, ovoid to cylindrical in slimy head or chains) are characteristic of the genus Fusarium. - In the clinical sample, the hyphae of Fusarium in tissue resemble those of Aspergillus spp. - The filaments are hyaline, septate, and 3–8 μm in diameter. - They typically branch at acute and at right angles.  Acremonium - The colonies are white-gray or rose in color, with a velvety to cottony surface. -The conidia are oval and 1 to 2 cells, in chains or in conidial masses, arising from short, unbranched, single, tapered phialides. -They are common soil saprophytes. - They cause nail infection and keratitis.  Phaeohyphomycetes Alternaria - Cladosporium -  Alternaria  - Colonies are fast growing, black to olivaceous-black or greyish,.  - Dematiaceous hyphomycete producing conidiophores.  - Microscopically, multicellular conidia (It has longitudinal and transverse walls) and grenade-shape are produced from simple, sometimes branched, short or elongate conidiophores.  Cladosporium - The colony grows rapidly. It is velvety to woolly and has a green, gray or black color. - Dematiaceous hyphomycete producing conidiophores. - The conidiophore has a dark color, and is branched at the end. - Conidia of 1 to 4 cells, with a smooth or spiny wall and brown in color, lead to the creation of chains with secondary branches that look like tree branches. - Non-pathogenic species have proteolytic properties.  Edible mushrooms - To date, about 2000 species of edible mushroom have been identified. - Some edible mushrooms, in addition to having completely edible organs, have some medicinal- therapeutic properties due to the presence of biologically active compounds (Bioactive), so they are called as edible-medicinal mushrooms. - Among the edible mushrooms, the following mushrooms can be mentioned:Agaricus bisporus, Lentinula edodes, Pleurotus spp, Tremella fuciformis, Grifola frondosa  Continue - Factors affecting the growth and development of edible mushrooms are affected by two categories of internal and external factors. - Internal factors include the inherent characteristics and genetic structure of edible mushrooms, which are different from one species to another and even different races or strains of the same species. - External factors include a set of necessary environmental conditions (including growth nutritional requirements, heat, humidity, light, ventilation and pH) for the growth of edible mushrooms. - One of the physiological characteristics of mushrooms, especially edible mushrooms, is their ability to decompose. The feature that is influenced by the internal factors of mushrooms more than any other factor, and therefore expresses their enzymatic power.  Continue - Genetic characteristics and the influence of external factors cause the production and secretion of a wide range of primary acids and enzymes that decompose organic substances in edible mushrooms. - This makes it easy for them to break down their substrate and use the resulting energy. - The feature that has made these edible mushrooms easily grow on a wide group of wood materials (lignin), cellulose and hemicellulose and materials with higher nutritional and medicinal value such as protein compounds, lipids, carbohydrates, vitamins and many make secondary metabolites.  Fungal poisoning 1) Mycotoxicosis: Poisoning and complications resulting from eating fungal toxins on food. 2) Mycetismus:The side effects of eating poisonous fleshy mushrooms are called mystismus.  Mycotoxins Mycotoxins are secondary metabolites, meaning they do not play a role in the normal metabolism of mushroom growth. Aflatoxin: This toxin is the most important fungal toxin Ochratoxin Fumonisin Trichotisin Zearalenone Why studying medical mycology is important? 1- In humans, fungi cause skin infections such as ringworm and athlete's foot. 2- They also cause several deadly diseases which can be hard to treat. 3- Most patients with deadly fungal diseases do not have a fully functional immune system. – Leukaemia – AIDS – Drugs to suppress their immune system because of organ transplantation. 4- Antifungal drugs are often toxic. 5- There is a desperate need for new and better anti-fungal agents.  When fungal infections should be considered?  Prolong fever not responding to antibiotics.  Neutropenia  Diabetes with ketoacidosis  Bone marrow and solid organs transplantation  HIV patients  Travel or stay in endemic areas. Mycoses can be classified according to the site of infection into: 1. Superficial 2. Cutaneous 3. Subcutaneous 4. Deep (systemic) 5. Other Mycoses Superficial Mycoses Structure of skin  Superficial Mycoses 1) Pityriasis versicolor 2) Piedras 3) Tinea nigra 4) Mycotic keratitis 5) Otomycosis  Pityriasis (Tinea)Versicolor Definition: This is a very common superficial mycoses caused by a lipophilic yeast Malassezia spp. It is seen in all countries but is particularly common in the tropics with more than 60 % of the population infected. The causal organisms and their habitate: On the basis of morphological, physiological and molecular methods nine Malassezia species were recognized: M.furfur, M.pachydermatis, M.sympodialis,M.globosa,M.obtusa,M.restricta,M.slooffia, M.dermatis,M.nana.  Clinical manifestation  The lesions are hypo or hyper pigmented. The etiologic agent is normal flora of man so the disease re-occurs.  Recent evidence suggest that seborrheic dermatitis is also caused, or triggered by, Malassezia yeast.  There also is Malassezia folliculitis. This is seen in patients who are usually severely ill or in patients after sun exposure.  Seborrheic dermatitis is a chronic relapsing scaling dermatosis of the fsce, scalp and trunk. This is pityriasis versicolor. Note the larger area of hypopigmentation in the center. In this disease there is no erythema, the infected areas are not elevated, and aside from some itching the patient feels no discomfort. This is a patient with pityriasis versicolor. Again, note the blotchiness of the skin pigmentation. Note the areas of hypopigmentation on the back of this patient. This again is tinea versicolor. Malassezia folliculitis (Pityrosporum folliculitis) Superficial malassezia folliculitis  Laboratory Diagnostic 1) Direct microscopic examination 2) Wood,s light 3) Culture This is a photomicrograph of skin infected with Malassezia furfur. Note that in vivo this organism produces clusters or clumps of rather short hyphae and spherical yeast cells. Some authors refer to this overall picture as “spaghetti and meatballs”. This is a high magnification of tinea versicolor. Note the round clump of yeast cells and the short strands of hyphae. This slide was made with 10% KOH and up to 10% Super Chrome ink or methylene blue stain was added.  Therapy 1) Tinea versicolor is one of the few places where ketoconazole is used universally ( a single 400 mg. dose or 5 days of 200 mg. is sufficient) for large lesions. Smaller infected areas can be treated with selenium sulfide in a shampoo or other topical antifungals. 2) Seborrheic dermatitis (dandruff) is treated the same as above. NOTE: Ketoconazole can be used safely for short term results. For other mycoses, requiring longer therapy, the newer drug Sporanox can be used with greater safety. Piedras a) Black Piedra b) White Piedra  a) Black Piedra This disease is characterized by small dark nodules seen on the hair shaft. It is found mostly in tropical areas such as South America..I have seen it in school children in Vietnam This is a higher magnification photograph of hair with black piedra. The lesion is very discrete, surrounds the hair shaft and is dark brown. Eventually the fungus may weaken the hair shaft to the extent that the hair breaks off. This is a still higher magnification of hair infected with Piedraia hortai. Close observation reveals that the nodule appears to be composed of hundreds of spherical cells. These cells are the asci, which contains ascospores. Such structures can be seen more clearly when one places infected hair in 1-2 drops of 10-20% KOH on a microscope slide, adds a coverslip, heats the preparation gently and the presses down very firmly on the coverslip. In such preparations the piedra nodules break open, and one sees many individual asci containing ascospores and, occasionally, groups of ascospores which have been squeezed out of individual asci. This is a culture of the fungus Piedraia hortai. This fungus was cultured on Sabourauds medium and incubated at room temperature. It normally takes 4- 6 weeks incubation weeks incubation for a colony to reach this size. The gross features of this colony are that it is slow-growing, is heaped up in the center, is a dark brown-black to metallic green and is surrounded by a clear ring where the young growing mycelium has not yet produced the dark pigment. Microscopically, there are few characteristic features. The fungus produces dermatiaceous hyphae which may contain numerous chlamydospores. No characteristic spores are produced.  b) White Piedra In this disease we also see nodules on the hair. However, differing from black piedra, the nodules are softer, pale in color and are only found on hair in the groin and axillae. In this picture we see hair with white piedra (Trichosporon beigelii). Note that, when this module is compared with that seen in black piedra, it is not as discrete and lacks the dark coloration. Additionally, this fungus does not produce ascospores. When cultured on Sabouraud’s agar and incubated for 2-4 weeks at room temperature, this fungus produces a rough, membranous, white to light tan colony. Microscopically, the organism produces no characteristic spores. This is a 4-5 week old culture of Trichosporon beigelii (T. cutaneum) grown on Sabourauds medium at room temperature. This is the etiologic agent of white piedra.  Therapy The piedras are treated by removal of the hair and application of topical antifungal agents(Shampo sulforeh 3%, Formalin 2%). Note: White piedra must be differentiated from trichomycosis axillaris which is bacterial in etiology.  Tinea Nigra This is a superficial infection caused by a black yeast variously known as Cladosporium or Hortaea werneckii. It is usually found in tropical areas of the world. It is seen as circumscribe areas of hyperpigmentation usually on the palms or soles. Lesions are dark brown to black with little scaling. This is a photograph of tissue prepared for direct examination with 10% KOH. Throughout the field one can readily observe strongly septate dematiaceous hyphae. Note: No coloring agent has been added to this slide; the dark brown color is produced in the fungus. This is how the etiologic agent of tinea nigra appears in tissue. An unusual case from the Philippines. Now you know why this disease is no longer called tinea nigra palmaris! A small portion scrapped skin, placed in 10% KOH on a microscope slide will reveal the dematiaceous, septate hyphae.  Therapy Topical antifungal agents as well as Whitefield’s ointment have been used successfully..Mycotic Keratitis An opportunistic fungal infection of the eye that causes ulceration and inflammation, usually following trauma to the cornea by vegetative matter, soil or surgery. Prolonged treatment with corticosteroids may also be a predisposing factor. Distribution: World-wide. Aetiological Agents: Various saprophytic fungi, especially Aspergillus fumigatus, A. flavus, A. niger, Fusarium solani and Candida albicans. Others include species of Alternaria, Curvularia, Pseudallescheria and Acremonium. This is a rather typical case of mycotic keratitis. The patient reported that several months previously some foreign matter had lodged in his eye. In this case of mycotic keratitis the lesion is very obvious. Scrapings from this eye were examined in KOH preparations, and septate hyphae were observed. Additional material was cultured, and the etiologic agent was identified as a Fusarium. The patient was given treatment with topical amphotericin B and responded in a satisfactory fashion. This is what one sees in cases of mycotic keratitis when infected tissue is observed microscopically under direct examination procedures. Note the presence of hyphae (A,B). This particular organism was cultured on Sabourauds medium and identified as an Aspergillus species. This, like the previous slide, is a direct examination preparation from a case of mycotic keratitis. Note the abundance of clear, septate hyphae (A,B). When structures of this nature are observed, there is no doubt that the etiologic agent is a fungus. This is a photomicrograph of Penicillium. Here we see the brushes (A) with a few spores (B) attached to them. This is the fungus Rhizopus, another etiologic agent of mycotic keratitis. There are 3 important features of species found in the genus Rhizopus: the hyphae (A) are relatively large (8-10 microns in diameter) and are coenocytic; the larger, spherical, dark blue structure in this photograph is a sporangium (B), and, under high magnification, one would see that it contains dozens of spores (sporangiospores); at the end of a piece of hypha, one can see a mass of finger- like projections, the so called rhizoids from which the genus name is derived. The purpose of the rhizoids is probably to hold the fungus to the subtrate and absorb nutrients. This fungus, Fusarium, is another etiologic agent of mycotic keratitis. This organism produces clear septate hyphae which are not particularly characteristic. The large macroconidia, shown here, are septate, new- moon/banana-shaped spores. Fusarium spp. also produce small spores called microconidia. This is a typical picture of an Aspergillus species. This fungus produces clear septate hyphae. Note the way the spores are borne. On the ends of the specialized pieces of hyphae (conidiophores) (A) is a swollen tip (vesicle) (B). On these vesicles, phialides (or sterigma) are present, and long strands of small spores (C ) are borne at the end of the sterigma. Aspergillus species cause otomycosis, mycotic keratitis and aspergillosis.  Therapy 1) A 5 % solution of natamycin applied topically. 2) Topically applied Amphotericin B, oral Sporanox (1:50 dilution of Sporanox in ophthalmic solution) and ketoconazole in suspension have been used in difficult cases. 3) If thermophilic Aspergillus spp. are involved the organism may invade the brain. Few drugs are successful in such cases.  Otitis Externa  Bacterial, viral or fungal infection of external auditory canal  Categorized by time course – Acute – Chronic  Organisms Pseudomonas species.1 Staphylococci.2 Streptococci/Gram negative rods.3 Fungi (Aspergillus/Candida species).4  Otomycosis Definition The term otomycosis is used to describe a superficial fungal infection of the ear canal. Geographical distribution The condition is worldwide in distribution, but is more common in tropical and subtropical regions. The causal organisms and their habitat Otomycosis is most commonly caused by Aspergillus species, particularly A.fumigatus, A.niger,A.nidulans and A.flavus, and Candida species,particularly C.albicans and C.tropicalis. A.niger is the most common cause of infection. Other moulds that have been implicated include Penicillium species, and Rhizopus species. Mixed bacterial and fungal cultures are common and account for more than 50% of all cultures in otomycosis.  Otomycosis Epidemiology The aetiological agents of otomycosis are commonly found in indoor and outdoor air, in the soil and dust, and on decomposing plant matter. Their prevalence varies with climatic conditions, but warm humid environments support their growth and the human ear canal is ideal for their proliferation.  Labs Diagnosis Material for mycological investigation should be obtained from the deposits blocking the ear canal. Microscopic examination will reveal branching hyphae, or budding yeast cells or both. In cases of Aspergillus infection, the typical sporing heads can sometimes be seen. Isolation of the aetiological agent in culture will enable the species of the fungus involved to be identified.  Treatment The treatment of otomycosis consists of removal of debris from the ear canal and thorough cleaning, together with the local application of an antifungal. Topical nystatin can be applied three times daily for 2-3 weeks. The local application of clotrimazole or econazole nitrate, also gives good results.  Cutaneous mycoses extend deeper into the epidermis, as well as invasive hair and nail diseases.  Infection of the skin, hair or nails caused by a group of keratinophilic fungi, called dermatophytes  DERMATOPHYTOSIS (=Tinea = Ringworm) Tinea means "ringworm" or "moth-like". Dermatologists use the term to refer to a variety of lesions of the skin or scalp.  DERMATOPHYTES  Digest keratin by their keratinases  Resistant to cycloheximide  Classified into three groups depending on their usual habitat  Dermatophytes 3 Genera  Trichophyton  Microsporum  Epidermophyton  Taxonomy of dermatophytes - Dermatophytes are in the ascomycete family. - They have anamorph (asexual stage) and teleomorph (sexual stage). - The name of the sexual stage of dermatophytes is Arthroderma. - All dermatophyte species except Trichophyton georgia are heterothallic.  Ecology of Dermatophytes To determine the source of infection  Anthropophilic  Zoophilic  Geophilic  Anthropophilic Associated with humans only. Person -to- person transmission through contaminated objects (comb, hat, etc.) T.Tonsorance T.Schoenleini  Zoophilic Associated with animals. Direct transmission to humans by close.contact with animals M.canis(dogs and cats) T.verrucosum(cattle)  Geophilic Usually found in soil. Transmitted to.humans by direct exposure M.gypseum Microsporum (13 species)  Skin  Hair  Microsporum 1)M.canis:Most common etiologic agent of tinea 2)M.audouinii 3)M.gypseum  M.canis - Cotton colony is characterized by yellowish white color and golden yellow pigment on the back of the colony. - Macroconidia produce 6-15 cells, spindle-shaped and with a mammary appendage at the end. The number of macroconidia is high. - The macroconidial cell wall is thick and spiny.The number of microconidia is small and oval. - It is animal friendly and exists in the body of cats and dogs. - The sexual stage is called arthroderma ota.  M.audouinii - The colony produces white or gray, the back of the colony is reddish brown. - In rare cases, spindle-shaped macroconidia are seen. - Microconidia usually not seen.Pectinate hyphae can be seen. - Terminal chlamydioconidia are also seen. - This dermatophyte is anthropophilic.  M.gypseum - Creates a velvety colony or a cream-colored seed. The color of the back of the colony is reddish brown. - Spindle-shaped macroconidia with a rounded end and a thinner wall than canis containing 3-9 cells are seen. - The number of microconidia is low. - It is soil-loving. - The name of its sexual stage is Arthroderma incurvata.  Trichophyton (19 species)  Hair  Skin  Nails  Trichophyton 1)T. rubrum 2)T. mentagrophytis 3)T.verrucossum 4)T.schoenleinii 5) T.tonsurans 6)T.violaceum  T. rubrum - It produces a seed or cotton colony, the back of the colony is ruby red. - The number of microconidia is low in normal environments and abundant in nutrient environments. - The macroconidia are small and cylindrical or pencil-shaped with 3-11 cells. - This dermatophyte is anthropophilic  T. mentagrophytis - It creates a velvety, powdery, granular and fluffy colony in white, yellow, pink and cream colors. Macroconidia are 3-8 cells with a smooth and thin wall and cigar-shaped. - Oval microconidia are seen singly and in clusters around the mycelium. - Spring-shaped (Spiral) and spiral (Coil) myceliums are formed. - This dermatophyte is zoophilic  T. Interdigital - It creates a velvety, powdery, granular and fluffy colony in white, yellow, pink and cream colors. Macroconidia are 3-8 cells with a smooth and thin wall and cigar-shaped. - Oval microconidia are seen singly and in clusters around the mycelium. - Spring-shaped (Spiral) and spiral (Coil) myceliums are formed. - This dermatophyte is anthropophilic  T.verrucossum - Creates a velvety, waxy, prominent and wrinkled colony. Colony growth is very slow. - Under the microscope, it can be seen in the form of chains of chlamydioconidia and sometimes a small number of small microconidia. - Legume-shaped macroconidia may rarely occur. Colony growth is better in the presence of thiamine and inositol. - It is present in the body of the cow.  T.schoenleinii - The colony grows slowly and becomes white and gradually pea colored. - Micro and macroconidia usually absent. - Antler myceliums with swollen ends (Antler hyphae) are one of the most important diagnostic factors of this fungus. - This dermatophyte is anthropophilic.  T.tonsurans - The colony is granular, velvety, and cottony and is seen in cream color. - Cylindrical macroconidia containing 2-10 cells with smooth walls are formed. - Microconidia are seen abundantly and in the form of teardrops. - This fungus grows better on media containing thiamine. - This dermatophyte is anthropophilic.  T.violaceum - The colony grows slowly and is created in the form of wax or skin. - The color of the colony is purple or violet. - Chlamydioconi and rarely micro and macroconidia are seen in this dermatophyte. - They grow better in an environment containing thiamine. - This dermatophyte is anthropophilic. Epidermophyton floccosum  Skin  Nails  Epidermophyton floccosum - It has a yellowish-green (olive) colony. - Macroconidia are club-shaped and pear-shaped with a thin and smooth wall. - It does not have microconidia. - This dermatophyte is anthropophilic.  DERMATOPHYTOSIS Clinical Classification & Manifestations Infection is named according to the anatomic location  Tinea Corporis - The attack of dermatophytes on the skin of the trunk, on the legs and hands is called ringworm. - Some types of trichophytons and microsporums as well as Epidermophyton flucosum cause the disease. - Disease-causing agents are often animal-loving and soil-loving. - Frequent infections occur in closely related families. - Infections may spread to other parts of the body.  Clinical manifestations - This disease usually affects bare areas of the body. - Natural dependence is essential in the infecting organism, infections caused by zoophilic species are often more inflammatory and may become purulent. - The infection manifests naturally with dry, round and scaly itchy lesions. - Fungi are more active in the margin of the lesions, so the margin of the lesion is more prominent.  Tinea capitis - The attack of dermatophytes on the hair and scalp is called tinea capitis. - Some types of trichophytons and microsporums are considered as disease-causing agents. - Microsporum canis is common as an zoophilic dermatophytic agent in southern Europe. - Tinea capitis is divided into three types: ectothrix (spores outside the hair shaft), endothrix (spores inside the hair shaft) and favus (mycelium inside the hair shaft). - Microsporum canis, gypseum, audeoni, trichophyton verrucosum, and Mentagrophytis are the causative agents of ectothrix head ringworm. - Trichophyton violaceum and tonsorans (both anthropomorphic) cause ringworm of the endothrix type. - Trichophyton schönelinei (anthropophyte) causes favus type baldness.  Reasons for the prevalence of tinea capitis in children - Transverse growth of hair is more in children. - Children's hair contains more keratin than adults. - Absence of fatty acids with medium chain - Absence of sex hormones  Clinical manifestations - Kerion lesions with high inflammation are caused by zoophilic dermatophytes, which are usually seen in the type of ectothrix. - Black dot manifestations are seen in the type of endotrix. - Scutula lesions (dry layer on the wound with exudate and secretion) can be seen in the favus type.  Tinea pedis or Athletes foot - The attack of dermatophytes on the feet (soles and toes) is called tinea pedis. - It is the most common type of baldness. - Walking with bare feet in polluted environments, swimming a lot and using closed shoes are important factors in people getting dermatophytic foot infection.  Clinical manifestations - Acute or chronic interdigital infection is itchy, crusting, cracking, and crushing between the toes, which is mostly caused by Epidermophyton flucosum. - Chronic stratum corneum with smooth, scaly white lesions confined to the soles or outer sides of the feet, this form of the disease is caused by Trichophyton rubrum. - Vesicular (inflammatory) infections, which are visible with the formation of vesicles on the soles and heels of the feet and creating cracks between the toes, this form of the disease is caused by Trichophytom Mentagrophytis.  Tinea cruris - The attack of dermatophytes on the groin area is called tinea groin. - The causative agents of the disease are anthropophilc dermatophytes, Epidermophyton flucosum and Trichophyton rubrum. - Moist, wet and wrinkled groin skin increases the incidence of the disease. - Often the infection spreads to other parts of the body. - There is severe transmission of infection through contaminated sheets and towels, contaminated ground.  Clinical manifestations - The presence of one or more red lesions with a healthy center along with intense itching in the inner part of the groin is seen, which spreads rapidly. - Lesions increase with brown background skin and red border.  Tinea mannum - The attack of dermatophytes on one or both hands (palms and fingers) is called tinea capitis. - Among the anthropophilic dermatophyte agents, Trichophyton interdigital, Trichophyton rubrum and Epidermophyton flucosum are often more common. - Microsporum canis, Trichophyton verrucosum, and Trichophyton Mentagrophytis are the most common dermatophytic agents. - Acquired infection occurs due to contact with infected people, infected animals, contaminated soil and transfer of secretions and fluids from infected wounds to other parts of the body.  Clinical manifestations - Lesions are usually unilateral and typically affect the right hand. - Eczema lesions, circular with clear and single borders, whose surface is covered with white scales. - Hyperkeratotic, vesicular, circular lesions with large scaling and white, red, inflamed with irregular boundaries are seen.  Tinea unguium - The attack of dermatophytes on fingernails or toenails is called ringworm. -Onychomycosis: The attack of yeast and filamentous fungi on nail tissue is called onychomycosis. -Trichophyton interdigital and Trichophyton rubrum are the most common agents of anthropomorphic dermatophytes. - Infection between the toes is caused by zoophilic dermatophyte species.  Clinical manifestations - Toes are often more infected than fingers. - Dermatophytic nail infections are often accompanied by infections in other parts of the body. - The most common anatomical site of the disease is the first and fifth toe, which is caused by the injury caused by hitting the toes when the patient walks with bare feet. - The disease begins with the appearance of irregular white or yellow lesions on the free end of the nail, which spreads slowly. - Lesions are accompanied by changes in the color, consistency and diameter of the nail, and there is a possibility of nail breakage. - Tinea barbae - ringworm of the bearded areas of the face and neck.  DERMATOPHYTOSIS Diagnosis I. Clinical Appearance Wood’s lamp (UV, 365 nm) II. Lab A. Direct microscopic examination (10-25% KOH)  ‫چراغ وود‬ ‫‪ -‬رنگ زرد مایل به سبز‪:‬‬ ‫میکروسپوروم اودوئینی‪ ،‬میکروسپوروم کانیس‪،‬‬ ‫میکروسپوروم فروجینوم‪ ،‬ترایکوفایتون‬ ‫منتاگروفایتیس واریته اریناسه ای و ترایکوفایتون‬ ‫سیمئی‬ ‫‪ -‬رنگ سفید متمایل به آبی تیره‪:‬‬ ‫ترایکوفایتون شوئن الینی‬ ‫‪( Hair‬اکتوتریکس)‬ ‫اندوتریکس‬ ‫فاووس‬  ‫پوست‬ ‫میسیلیوم‪+‬آرتروکونیدی‬  DERMATOPHYTOSIS Diagnosis B. Culture Mycobiotic agar DTM medium Sabouraud dextrose agar  DERMATOPHYTOSIS Treatment  Topical Miconazole, clotrimazole, econazole, terbinafine...  Oral Griseofulvin Ketaconazole Itraconazole Terbinafine