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  1. 1. MYCOLOGY Dr. Fatima Fasih Pathology Department DUHS
  2. 2. 1. Introduction and Classification of fungal infections (mycoses) 2. Types of Cutaneous & Subcutaneous mycoses 3. Characteristic of cutaneous & subcutaneous mycoses 4. Types of systemic and opportunistic mycoses 5. Lab diagnosis 6. Treatment Lecture Objectives
  3. 3. Greek word(mykes) meaning mushroom. Early 19th century- First documented animal infection by any fungus was made by Bassi. 1910-Raymond Sabourad –Published book (Les Teigens)  Comprehensive study of dermatophytic organism in various field of life. Mycology
  4. 4.  Decomposition  Biosynthetic factories  Source of antibiotic  Model organism – study biochemical and genetic studies- Neurospora crassa  Use in Recombinant DNA technology- Saccharomyces cerviciae. Benefical effects of Fungi
  5. 5.  Destruction of food,paper and cloth  Animal and human diseases  Plant disease  Spoilage of agriculture produce Harmful effects of Fungi
  6. 6. Introduction
  7. 7. Classification of Fungi Based on sexual reproduction Ascomycetes Basidiomycete s Deuteromycete s Zygomycetes
  8. 8. Based on morphology Yeast Mould Yeast like Dimorphic Mould(Molds) : Filamentous fungi e.g Aspergillus spps,Trichophyton rubrum Yeast: Singled celled cells that buds e.g Crytococcus neoformans ,Saccharmyces cerviciae Yeast Like: Similar to yeast but produce pseudohyphae E.g Candida albicans Dimorphic: Fungi existing in two different morphological forms at two different environmental conditions. They exist as yeast in tissue and in vitro at 37 C and as moulds in their natural habitat and in vitro at room temperature. e.G Histoplasma capsulatum, Blastomyces dermatiditis,Paracoccidiodes.
  9. 9.  The thallus of mould is made of hyphae.  Hyphae- cylindrical tube like structure.  Mycelium- mass of hyphae is known as mycelium.  Presence of hyphae – filamentous nature of mould. Mould
  10. 10. Types of mycelium Aerial Vegetative Fertile  penetrates the surface of the medium and absorbs nutrients grow above the agar surface Aerial hyphae that bear reproductive structures such as conidia and sporandia
  11. 11.  Spiral Hyphae:  Trichophyton mentagrophytes  Pectinate body:  short,unilaterial projections from the hyphae that resemble a broken comb Type of Hyphae
  12. 12.  Favic chandelier; group of hyphae tips that resembles antlers of the deer.  Trichophyton schoenleninii, Trichophytonviolaceum
  13. 13. Nodular organ : Enlargement in the mycelium –consist of twisted hyphae. Trichophyton mentagrophytes Microsporum canis Racquet hyphae: regular enlargment of one end of each segement with the opposing end remaning thin. Epidermophyton floccosum.
  14. 14. Rhizoids Root like structure Seen in vegetative hyphae in some members in zygomycetes.
  15. 15. Prolonged antibiotic therapy Underlying disease HIV infection, cancer,diabetes Immunosuppressantagents& chemotherapy,indwellingcatheters,drug addiction Age, obesity, transplant, occupation Predisposing factors
  16. 16. Pathogenesis of Fungal diseases  Except for few fungi such as dimorphic fungi that cause systemic mycoses and which are dermatophytes which are primary pathogens.  Rest are only opportunistic pathogens.  Reason  Human – hostile enviroment  Great resistance to fungal infection.  Fungi: saprophytic  Enzymetic pathways function –efficiently-at redox potential of non living substrates.
  17. 17.  Compared to reduced state of living metabolizing tissue.  Candida and Malasezzia have adapted to human environment and exist as commensals.
  18. 18. Complex interplay Virulent factors Host defense factors Fungal infection- disease
  19. 19. Virulent factors cell wall glycoprotein • Adhesin to host cell. capsule • resist phagocytosi s cytotoxin • E.G Candida albicans • GM-CSF • Suppress the production of complement
  20. 20. Secreting enzyme • Keratinase • Collagenase • elastase mycotoxins Thermal dimorphism
  21. 21. Host defense factors  Physical barriers – skin, mucus membrane  Fatty acid content of skin  pH of the skin, mucosal membrane and body fluids.  Normal flora.  Chemical barriers: secretions, serum factors  Natural Effector Cells- polymorphonuclear leucocytes.  Professional Phagocytes – monocytes and macrophages
  22. 22. 1. Cutaneous 2. Subcutaneous 3. Systemic 4. Opportunistic Classification based on location
  23. 23.  Dermatophytoses  Tinea Versicolor  Tinea Nigra Cutaneous mycoses
  24. 24. • A fungus that cause infections of skin, hair & nails due to their ability to obtain nutrients from keratinized material. • Acquired due to contact with soil, infected animal / human • They colonize the keratin tissues & cause inflammation in response to metabolic by- products Dermatophytoses Caused by dermatophytes
  25. 25. Classified into 3 genera 1. Epidermophyton 2. Trichophyton 3. Microsporum Dermatophytes
  26. 26.  Infect superficial keratinized structures Skin, hair & nails  Spread by direct contact with infected person / animal e.g. dogs & cats Characteristics of dermatophytic infection
  27. 27.  Chronic infection  Occur in warm, humid areas of body e.g. foot, groin Dermatophytoses (Tinea/ ring worm)
  28. 28. Inflamed circular border  Containing papules & vesicles surrounding  Clear area of normal skin,having broken hair & thickened nails Characteristic of typical ring worm
  29. 29. Typical ring worm infection
  30. 30.  Tinea capitis (head)  Tinea corporis (body)  Tinea cruris (groin)  Tinea pedis (foot) Dermatophytoses a/c body site
  31. 31. Tinea capitis
  32. 32. Tinea corporis
  33. 33. Tinea pedis
  34. 34.  Trichophyton tonsurans  Trichophyton rubrum  Trichophyton schoenleinii Types of Tinea Capitis
  35. 35.  Most common cause of Tinea capitis in children  Main cause of endothrix ( hair infection ) Trichophyton tonsurans
  36. 36.  Hypersensitivity reaction  In response to fungal antigens  Vesicles on fingers  Skin test positive in pts with tinea infection Dermatophytid reaction
  37. 37.  10% KOH preparation & microscopic examination of skin scrapping & nail  Fungal culture on Sabouraud’s agar  Tinea lesions caused by Microsporum sp. become fluorescent when exposed to ultraviolet light by wood lamp. Lab diagnosis
  38. 38. Sabouraud’s agar
  39. 39.  Local antifungal cream like Undecylenic acid Miconazole Tolnaftate  Oral antifungal drug like Griseofulvin Treatment
  40. 40. Keep skin dry & cool Prevention
  41. 41.  Caused by Malassezia furfur  Superficial skin infection  Cosmetic importance Tinea versicolor
  42. 42.  Lesions appear as hypopigmented areas  Frequent in humid & hot weather  Occur most commonly on tanned skin  Associated with scaling of skin & itching Tinea Versicolor Main characteristics
  43. 43. KOH preparation of skin scrapping Lab diagnosis
  44. 44.  Topical Miconazole  Lesion may recur  Difficult to have permanent cure Treatment
  45. 45. Tinea Versicolor
  46. 46.  Infection of keratinized layer of skin  Causative organism, Cladosporium werneckii Tinea nigra
  47. 47.  Appear as brownish spot  Due to melanin like pigment in hyphae Tinea Nigra Main characteristic
  48. 48. Tinea nigra
  49. 49.  Topical keratolytic agent Salicylic acid Treatment
  50. 50.  Fungi enter traumatic subcutaneous tissue  Caused by fungi that grow in soil & on vegetation Subcutaneous Mycoses
  51. 51.  Sporotrichosis  Chromomycosis  Mycetoma Types of subcutaneous mycoses
  52. 52.  Causative organism : Sporothrix schenckii  Dimorphic fungus, lives on vegetation  Occur most commonly in gardeners.  Introduced into skin by a thorn, causing pustule/ulcer Sporotrichosis
  53. 53. Sporotrichosis
  54. 54.  Topical antifungal ointment for skin lesion Itraconazole Treatment
  55. 55. Protecting skin while touching plants, moss & wood Prevention
  56. 56.  Appear as cigar shaped budding yeast in tissue specimen microscopy  In culture hyphae are formed bearing conidia resembling daisy Lab diagnosis
  57. 57. Moss
  58. 58. • Wart like lesions • Have crusting abscesses • Common in tropics • Lesion commonly found on bare feet & legs Chromomycosis Characteristics
  59. 59.  Slowly progressive granulomatous infection  Causative organism: Fonsecaea Phialophora Cladosporium  Called Dematiaceous fungi, b/c of gray or black color hyphae. Chromomycosis
  60. 60. Chromomycosis
  61. 61. Dark brown & round fungal cells in leukocytes seen on microscopy Lab diagnosis
  62. 62. Oral flucytosine / Thiabendazole Local surgery Treatment
  63. 63.  Causative organism: Petriellidium , Madurella  Produce abscesses & pus draining sinuses  Common sites are hand & foot Mycetoma
  64. 64. Mycetoma
  65. 65. No effective antifungal drug Surgical excision is recommended Treatment
  66. 66. Systemic infection • Blastomycosis • Histoplasmosis • Coccidioidomycosis
  67. 67. Blastomycosis It is a fungal infection, also known as North American Blastomycosis caused by the organism Blastomyces dermatitidis.
  68. 68. Blastomyces dermatitidis is a dimorphic fungus that exist as mold in soil and as a yeast in tissue. Blastomycosis
  69. 69. Transmission • This fungus grows in moist soil rich in organic material, forming hyphae with small pear shaped conidia. • Inhalation of the conidia causes human infection Blastomycosis
  70. 70. It can present in one of the following ways:  A flu-like illness with fever, chills, myalgia, headache, and a nonproductive cough which resolves within days. An acute illness resembling bacterial pneumonia, with symptoms of high fever, chills, a productive cough, and pleuritic chest pain.  A chronic illness that mimics tuberculosis or lung cancer, with symptoms of low-grade fever, a productive cough, night sweats, and weight loss. Blastomycosis
  71. 71. • In tissue biopsy specimen, thick walled yeast cells with single broad based buds are seen microscopically. • Hyphae with small pear shaped conidia are visible on culture. The skin test lacks specifically and has little value. Laboratory diagnosis
  72. 72. • Itraconazole drug of choice for most patients. • Amphotericin B used to treat severe disease • Surgical excision may be helpful • There is no means of prevention Treatment & Prevention
  73. 73. It is a disease caused by the fungus Histoplasma capsulatum. It is a dimorphic fungus , exist as mold in soil and as a yeast in tissue. Form two types of asexual spores, Tuberculate macroconidia, Microconidia important in laboratory identification. Histoplasmosis
  74. 74.  Histoplasmosis is contracted from contact to soil, particularly if soil is heavily contaminated with bird droppings.  Birds are not infected, bats are infected and can excrete the organism.  Excavation of soil during construction or exploration of bat infected caves has resulted in significant number of infected individuals. Transmission
  75. 75.  It primarily affects the lungs. Occasionally, other organs are affected; this is called disseminated histoplasmosis.  It can be fatal if left untreated. Histoplasmosis is common among AIDS patients because of their suppressed immune system Histoplasmosis
  76. 76. Laboratory diagnosis • In tissue biopsy specimens or bone marrow aspirates, oval yeast cells within macrophages are seen microscopically. • Culture on sabourad’s agar show hyphae with tuberculate macroconidia. • Serological test include complement fixation, immunodiffusion Histoplasmosis
  77. 77. No therapy is needed in asymptomatic or mild primary infections. In progressive lung lesions, oral itraconazole is beneficial. In disseminated disease, amphotericin B is treatment of choice. Treatment & prevention
  78. 78. It is a fungal disease caused by Coccidioides immitis. It is a dimorphic fungus that exist as mold in soil and as a spherule in tissue Coccidioidomycosis
  79. 79. Coccidioidomycosis Transmission: Infection is caused by inhalation of the particles (arthrospores) swept into the air by disruption of the soil, such as during construction, farming, or an earthquake. It is not transmitted from person to person.
  80. 80. • In lungs, arthrospores form spherules that are large (30um in dia) have, doubly refractive wall and filled with endospores. • Granulomatous lesion can occur in any organ but primarily in bones and CNS (meningitis) Pathogenesis
  81. 81.  Some infected person have influenza like illness with fever and cough.  50% have changes in lungs ( infiltrates, adenopathy, effusions) when seen on chest x-ray.  Disseminated disease can occur in almost any organ esp. meninges, bone, skin. Clinical findings
  82. 82. Serious complications include severe pneumonia, lung nodules, and disseminated disease, where the fungus spreads throughout the body Coccidioidomycosis
  83. 83.  In tissue specimens, spherules seen microscopically.  Culture on Sabouraud’s agar incubated at 25oC show hyphae with arthrospores. Cultures are highly infectious. Precautions against inhalation of arthrospore should be taken. Laboratory Diagnosis
  84. 84. • Amphotericin B or itraconazole is used for persisting lung lesions or disseminated disease. • Patients recovered from coccidiodal meningitis should receive long term suppressive therapy with fluconazole to prevent recurrence Treatment & Prevention
  85. 85. Opportunistic mycosis • Candidiasis • Cryptococcosis •Aspergillosis
  86. 86. Candidiasis • It is a fungal infection (mycosis) of any of the Candida species (all yeasts), of which Candida albicans is the most common. • It causes thrush, vaginitis, esophagitis, diaper rash & chronic mucocutaneous candidiasis.
  87. 87. Properties Candida albicans is an oval yeast with a single bud. It is part of normal flora of mucous membranes of • Upper respiratory tract • Gastrointestinal tract • Female genital tract • Candidiasis
  88. 88. Presence of candida on skin predispose to infections involving instruments that penetrate skin such as needles and indwelling catheter. Skin invasion occur in warm, moist areas. Transmission Candidiasis
  89. 89. Candidiasis encompasses infections that range from superficial, such as oral thrush & vaginitis, to systemic and potentially life-threatening diseases. Symptoms of candidiasis vary depending on the area affected. Most candidial infections result in minimal complications such as redness, itching and discomfort Candidiasis
  90. 90. Clinical findings • Persons employed as dishwashers in restaurants and institutions are commonly affected. • Thickening or loss of the nail can occur. • Diaper rash in infants when wet diapers are not changed promptly. Candidiasis
  91. 91. In exudates or tissues, budding yeast and pseudohyphae appear as gram positive and can be visualized by using calcoflour white staining. In culture, yeast colonies resemble as large staphylococcal colonies. Germ tube test is used to differentiated C. albicans from most other candida species. Laboratory diagnosis
  92. 92. • Drug of choice for oropharyngeal or esophageal thrush is fluconazole. • Caspofungin or micafungin can also be use for esophageal candidiasis. • Skin infections can be treated by topical antifungal drugs (clotrimazole or nystatin). Treatment & Prevention
  93. 93. Aspergillosis Aspergillosis is caused by a fungus Aspergillus, which is commonly found growing on dead leaves, stored grain, compost piles, or in other decaying vegetation.
  94. 94. Infections caused by the fungus rarely occur in people who have a normal immune system. The rare infections caused by aspergillus include pneumonia and fungus ball (aspergilloma). Aspergillosis
  95. 95. Laboratory diagnosis of fungal infections Assignment # 1

Hinweis der Redaktion

  • Papules & vesicles
  • Vegetation : abnormal growth over body part
  • pustule is a small collection of pus in the top layer of skin (epidermis