Micro Test 3: Superficial & Dermatophytoses Mycoses

  1. Tubular branching structure
  2. Colony
  3. Mass of intertwining hyphae
  4. Cross wall with central pore to produce continuous mass of cytoplasm (coenocytic)
  5. Hypha
    Tubular branching structure
  6. Thallus
  7. Mycelium (2 types)
    • Mass of entertwining hyphae
    • 1)  Vegetative:  Grow into/ penetrate medium
    • 2)  Aerial:  Project above the sruface of the medium
  8. Septa
    Cross wall with central pore to produce continuous mass of cytoplasm (coenocytic)
  9. 2 Cell membrane components of fungi
    • Ergosterol
    • Zymosterol
  10. 3 Cell wall components of fungi
    • Chitin (N-acetylglucosamine in B-1,4 glycosidic bonds)
    • Glucan (B-1,6 D-glucose)
    • Mannan (a-1,6 D-mannose)
  11. Anamorphs produce by
    asexual reproduction
  12. Organisms that produce by asexual reproduction are also known as
  13. Anamorphs are imperfect fungi that reproduce by 3 mechanisms.
    • 1)  Sporulation (and subsequently germination)
    • 2)  Blastospore formation (budding)
    • 3)  Fragmentation of hyphae
  14. 5 Types of asexual spores
    • Conidia
    • Arthrospores
    • Blastospores
    • Chlamydospores
    • Sporangiospores
    • (The asexual with CHLAMYDia took the CAB SPORting event.)
  15. Asexual single spores developing at tip of specialized hyphae.
    Conidia, hyphae are known as conidiophores
  16. Asexual spores that develop within the hyphae and released by fragmentation of hyphae.
  17. Asexual buds that develop from yeast-like cells.
  18. Asexual spores:
    1)  Develop single spores at tip of specialized hyphae
    2)  Develop within hyphae --> fragmentation
    3)  Develop from yeast-like cells
    4)  Develop from intercalated hyphal cells
    5)  Sac-like structures that develop at end of specialized hyphae
    • 1)  Conidia
    • 2)  Arthrospores
    • 3)  Blastospores
    • 4)  Chlamydospores
    • 5)  Sporangiospores
  19. Asexual thick walled spores that develop from terminal or intercalated hyphal cells (resistant to drying, heat)
  20. Asexual sac-like structures (______) that develop at the end of specialized hyphae (_______).
    Sporangiospores (sporangia, sporangiospores)
  21. Organisms that reproduce via sexual reproduction are known as _______ or _______
    Teleomorphs, Perfect
  22. Cells from a single colony that can engage in sexual reproduction
    Homothallic species
  23. Two different colonies of opposite mating types that can reproduce via sexual reproduction.
    Heterothallic species
  24. 2 Types of fungi species that reproduce sexually
    • Homothallic:  cells from a single colony
    • Heterothallic:  2 different colonies of opposite mating types
  25. Name 3 areas of the body from which fungi can be collected.
    • 1) Hair, skin, nails
    • 2)  Eye specimens
    • 3)  Body fluids
  26. Name 2 types of agar used to grow fungi.
    • SAB:  Sabouraud's Agar
    • PDA:  Potato Dextrose Agar
    • (High carb content, pH= 4- 6.5)
  27. Name 2 antigens which can confirm diagnosis of fungi if present.
    • Cryptococcal antigen
    • Histoplasma antigen
  28. What is used to dissolve cellular elements of fungi?
  29. Name 3 clinical syndromes caused by fungi.
    • Mycotoxicoses
    • Hypersensitivity Diseases
    • Colonization of the host and resultant disease
  30. Mycotoxicoses can be caused by
    • Ergot Alkaloids (St. Anthony's fire, alpha adrenergic blockers, oxytocic agents)
    • Psychotrophic Agents
    • Aflatoxins
    • Accidental ingestion of non-edible mushrooms
  31. Hypersensitivity due to fungi (mold):
    1)  Measure the degree of air pollution in "______"
    2)  Stimulates production of ______, leading to sensitized lymphocytes
    3)  Hypersensitivity pneumonitis including rhinitis, bronchial asthma, alveolitis, various forms of atopy
    • 1)  Fungal spore count
    • 2)  antibodies
  32. Name 5 Types of Mycoses
    • Superficial mycoses
    • Cutaneous mycoses
    • Subcutaneous mycoses
    • Systemic mycoses
    • Opportunistic infections
  33. This type of mycoses infection is limited to the outermost layers of the skin and hair.  It is usually a cosmetic response (no physical discomfort) that does NOT elicit a cellular response from the host and responds well clinically.
    Superficial mycoses
  34. 2 Superficial Mycoses that infect the stratum corneum.
    • Pityriases versicolor
    • Tinea nigra
  35. Pityriasis versicolor and Tinea nigra affect the ____
    stratum corneum (superficial mycoses)
  36. Superficial mycoses hair infections involve which portion of the hair?  What are 2 examples?
    • Cuticle of hair
    • Black piedra, white piedra
  37. Causative agent of Pityriasis versicolor
    Malassezia furfur (Pityrosporum orbiculare); part of normal flora, found in areas of the body rich in sebaceous glands
  38. Malassezia furfur causes _____ and grows as _______
    Pityriasis versicolor, budding yeast (hyphal forms occassionally seen)
  39. Spaghetti & meatballs appearance when treated with KOH is diagnostic of ______
    Pityriasis versicolor
  40. Name 2 symptoms of Pityriasis versicolor
    • 1) Discrete hyper- or hypo-pigmented macular lesions, usually on trunk or arms
    • 2)  Dry, scaly, chlaky appearance

    *Lesions fluoresce yellow-green under Wood's light
  41. How do you distinguish the lesions of Pityriasis versicolor vs. other macular lesions?
    They flouresce yellow-green under Wood's light.
  42. What must be present in the medium to culture Pityriasis versicolor?
  43. Name 4 things used to treat Pityriasis versicolor
    • Topical azole cream
    • 2% selenium sulfide lotion
    • 20% Na thiosulfate lotion
    • Oral ketoconazole or itraconozole (in extreme cases)
  44. Type of mycoses that affects the skin, hair, and nails.  It is generally restricted to keratinized layers.
    Cutaneous mycoses (also known as dermatophytoses)
  45. Which type of mycoses causes a cellular immune response, superficial or cutaneous?
    Cutaneous (C=C)
  46. 3 Classifications of Dematophytes
    • Anthrophilic:  exclusively infect humans
    • Geophilic:  Soil inhabiting, infect both humans and animals
    • Zoophlic:  essentially pathogens of lower animals but animal-to-human transmission is not uncommon
  47. Dermatophytes
    Cutaneous Mycoses
  48. Class of dermatophyte that almost exclusively infects humans
    Anthropophilic (anthro = humans)
  49. Class of dematophyte that inhabits the soil and infects both humans and animals
  50. Class of dermatophyte that is essentially a pathogen of lower animals but anima-to-human transmission is not uncommon
  51. 3 Genera of Dermatophytes
    • Trichophyton species (19)- infect skin, hair and nails
    • Microsporum species (13)- infect skin and hair, rarely nails; easily identified because hairs fluoresce a bright green color when illuminated with a UV-emitting wood's light
    • Epidermophyton floccosum- infect skin and nails, rarely hair
  52. The dermatophyte trichophyton infects
    skin, hair, and nails
  53. The dermatophyte microsporum infects
    skin and hair, rarely nails; hair fluoresces a bright green color when illuminated with a UV emitting wood's light
  54. Dermatophyte epidermophyton floccosum infects
    Skin and nails, rarely hair
  55. Ringworm/ tinea is a _____ and thus infects what portion of the skin?
    dermatophyte; keratinized layers
  56. Exothrix
    Dermatophyte infection that grows on outside of hair shaft
  57. Endothrix
    Dermatophyte infection that invades hair shaft
  58. Anatomical sites of dermatophytes:
    Tinea capitis: 
    Tinea barbae:
    Tinea corporis:
    Tinea cruris: 
    Tinea pedis:
    Tinea mannum:
    Tinea unguium:
    • ¢Tinea capitis:  hair and scalp
    • Exothrix: grows on outside of hair shaft
    • —Endothrix: invades hair shaft
    • ¢Tinea barbae: infections of beard area
    • ¢Tinea corporis:  infections on the trunk
    • ¢Tinea cruris:  infections of inguinal area
    • ¢Tinea pedis:  infections of the foot
    • ¢Tinea mannum: infections of the hand
    • ¢Tinea unguium: involvement of the nails
  59. Tinea pedis is what type of mycoses?
    Cutaneous mycoses/ dermatophyte
  60. Describe Tinea pedis.  Where does it start, what are its symptoms?
    Athlete's foot.  Starts in lateral interdigital spades and may spread to dorsum of foot. Symptoms include itching, cracking, and maceration (softening of skin due to autolysis) between the toes
  61. Describe Tinea cruris. Where does it start and what are its symptoms?
    Usually involves anterior thighs and begins with scaling and irritation in the groin. (primarily seen in young men and may also effect women)
  62. Describe Tinea corporis.  What do the lesions look like?
    Prominent edge with less inflamed center; scaly; can be single or multiple and may be hyperpigmented or itch.

    Differential diagnosis includes eczema, psoriasis or annula erythema.
  63. Symptoms of Tinea capitis.
    Scaling with variable degree of erythema, inflammation, alopecia, and itching
  64. Tinea Unguium causative agent.
    T. rubrum
  65. Usually associated with nail thickening and discoloration.
    Common in older individuals and involves fingernails or toenails.
    Tinea unguium
  66. 3 Agents of Otomycosis
    • Aspergillus niger
    • A. fumigatus
    • Mucor spp.
  67. Superficial, chronic or subacute infection of outer ear canal
  68. Otomycosis is an infection of what portion of the ear canal?  Symptoms?
    • Outer
    • Inflammation, scaling, itching and pain
  69. 3 Agents of Mycotic Keratitis
    • Aspergillus spp.
    • Fusarium spp.
    • Candida spp.
  70. Mycotic Keratitis is an infection of what?
    Surface of cornea
  71. Infection on the surface of the cornea
    Mycotic Keratitis
  72. Candidosis infects:
    • Superficial:  Oral and vaginal
    • Intertrigonous areas and nails
  73. Disease of superficial oral and vaginal surface as well as intertrigonous areas and nails.
  74. 5 Subacute Mycoses
    • Sporotrichosis
    • Chromomycosis
    • Phaeohyphomycosis
    • Mycetoma
    • Rhinosporidiosis
  75. Sporotrichosis, Chromomycosis, Phaeohyphomycosis, Mycetoma, Rhinosporidiosis are examples of?
    Subcutaneous Mycoses
  76. Sporotrichosis:
    1)  How do you get infected?
    2)  Produces ulcerated nodule, sometimes associated w/ ____
    3)  May also disseminate Hematogenously to ___ and ___ in normal individuals
    4)  Found most often on _____
    • Innoculation into skin
    • Lymphatic spread
    • Bone & CNS
    • Extremities
  77. Sporotrichosis therapy
    Itraconazole, amphtericin B
  78. Itraconazole and amphotericin B are used to treat
  79. 3 Causative agents of Chromomycosis
    • Phialophora (Fonsecea) pedrosoi
    • P. compacta
    • P. verrucosa
    • Cladosporium carrionii
  80. Describe Chromomycosis
    What is produced in exudate?
    • Chronic fungal infection that remains localized.  Characterized by warty nodules, usually on the lower legs.
    • Lesions usually enlarge and group with small ulcerations (black dots).
    • Sclerotic bodies produced in tissue and exudate ("copper pennies")
  81. Characterized by warty nodules, usually on the lower legs
  82. What disease produces sclerotic bodies "copper pennies" in tissue and exudate, and black dot lesions?
  83. Localized, chronic, noncontagious infection involving cutaneous and subcutaneous tissues
  84. Mycetoma caused by filamentous fungi
  85. Eumycetoma
    Mycetoma due to filamentous fungi
  86. Develops weeks to months after traumatic injury, tissue becomes indurated, abscesses develop and drain to sinuses
  87. Mycetoma:  Granulomatous tissue may invade as deep as?
    bony tissue
  88. Why is it important to distinguish between eumycetoma and mycetoma?
    Different bacterial agents involved
  89. What is tx for Mycetoma
    • Ketoconazole, itraconazole, amphetricin B
    • Continue for 10 months
  90. Infections caused by the dematiaceous, or black mold containing melanin in its cell wall; dark.
  91. Associated with allergic fungal sinusitis and brain abscesses
  92. Tx of Phaeohyphomycosis
    • Surgical draining or excision
    • Epidural or brain abscesses = Amphotericin B
    • Long term sinusitis = Itraconazole
    • Meningitis = Voriconazole
  93. What fungus is isolated from cerebrospinal fluid?
    Exserohilum rostratum
  94. Exserohilum rostratum is found in
    CEREBROSPINAL FLUID, plant debris, soil, and water
  95. Infection with Exserohilum rostratum is uncommon and usually is restricted to
    allergic sinusitis, keratitis, and localized soft-tissue infection (in rare cases, can be invasive in immunocompromised patients)
  96. Serveral outbreaks of what fungus have been associated with black mold contamination in the past decade?
    Exserohilum rostratum
  97. What species of exserohilum rostratum has been associated with meningitis due to contaminated glucocorticoid injections?
  98. What species of Exserohilum rostratum was identified as the causes of an outbreak associated with contaminated water?
    Exophiola jeanselmei
  99. What is the usual drug of choice for infection with dematiaceous fungi?
    An azole
  100. An azole is the usual drug of choice for infection with?
    Dematiaceous fungi
  101. Which drug, when given in high doses, has toxic effects?  Now what drug is given instead
    • Amphotericin B
    • Voriconazole
  102. If there is 100 mg of Voriconazole in the serum, how much is in the CSF?
    • 50 mg in CSF
    • Levels of drug in CSF are approximately 50% of serum levels, and levels in both CSF and serum are above the MIC for dematiaceous molds
  103. Which drug can achieve substantial levels in cerebrospinal fluid and thus is used to treat Exserohilum rostratum, Posaconazole, Itraconazole, or Voriconazole?
    Voriconazole is the only one that achieves substantial levels in CSF.
  104. Invasive fungal sinusitis is associated with (3 things)
    Malignancies, neutropenia, diabetes
  105. If a patient has chronic sinusitis and it fails to respond to repeated courses of antibiotics, then you should consider?
    Fungal sinusitis
  106. Proptosis
    Forward displacement of eyeball
  107. Calcification of sinus on CT, allergic rhinitis, nasal polyps, asthma, and proptosis (in children) are all symptoms of?
    Noninvasive fungal sinusitis (occurs in immunocompetent patients)
  108. Tx of invasive fungal sinusitis
    • Emergency surgery to remove necrotic and devitalized tissue
    • Treatment with Amphotericin B
    • Discontinue immunosuppression (ie. corticosteroids)
  109. 2 things that fluoresce under Wood's UV light
    • Pityriasis versicolor
    • Microsporum
Card Set
Micro Test 3: Superficial & Dermatophytoses Mycoses
Superficial & Dermatophytoses Mycoses