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2010-05-19 09:46:13
fungi microbiology

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  1. Fungi: saprobes
    organisms that live on dead or decaying matter
  2. Fungi Eukaryotic

    Cell wall?
    cell membrane ?
    Cell wall rigid & composed of chitin & glucan

    Ergosterol is substituted for cholesterol
  3. Hyphae
    Long, branching filamentous cells of fungus
  4. Conidia
    Asexual, non-motile spores of fungus. Can form at the tips of the growing hyphae on a specialized structure called a conidiophire
  5. Yeasts are unicellular or multicellular?
  6. Molds are unicellular or multicellular?
  7. Arthrospores (arthroconidia) are...
    Asexual, formed from fragmentation of septated hyphae into single cells
  8. Chlamydospores (chlamydoconidia) are
    Asexual, Thick-walled spore, formed by rounding and enlargement within hyphael segment
  9. Sporangiospores are
    asexual, Endospores inside spherules (sporangia) in tissue
  10. Rhizopus growth? phylum?
    Non septated hyphae, Zygomycota
  11. Aspergillus growth? Phylum?
    Dimorphic Ascomycota
  12. Blastomyces growth? Phylum?
    Yeastlike Ascomycota
  13. Histoplasma growth? phylum?
    septated hyphae, Ascomycota
  14. Coccidioides immitis growth? phylum?
    Septated hyphae, Ascomycota
  15. Candida albicans growth and phylum?
    Septated hyphae, Ascomycota
  16. Pneumocystis growth & phylum?
    Septated hyphae, Ascomycota
  17. Cryptococcus neoformans growth & phylum?
    Septated hyphae, Basidiomycota
  18. Dimorphic pathogens are
    Thermal (exist as yeasts or spherules at 37° C and molds at 25° C)
  19. Which mycoses causes superficial infection, pityriasis versicolor- discoloration or depigmentation and scaling of the skin
    Malassezia furufr
  20. Dermatophytoses caused by
    Tineas- ringworms
  21. Onychomycosis caused by
    Trychophyton rubrum
  22. Subcutaneous mycoses infections (sporotrichosis) caused by
    Sporothrix schenckii
  23. India ink used to diagnose which pathogen?
    Cryptococcus neoformans
  24. Blastomyces dermatitidis dimorphic or no? Infection via...?
    Dimorphic. Infection is by inhalation of aerosolized conidia (areas of moist soil, decomposing organic debris). Common infection among dogs
  25. Blastomyces dermatitidis causes? dissemination?
    Blastomycosis (may resemble TB). Dissemination via infected macrophages to skin, bone, urinary tract, CNS in immunocompromised.
  26. Histoplasma capsulatum dimorphic? What stain is used? Known to be...
    Dimorphic. Giemsa stain. Most common pulmonary and systemic mycosis of humans.
  27. Histoplasma capsulatum has 2 conidia forms
    1.Large (8 to 15 μm), thick-walled, spherical macroconidia with spikelike projections (tuberculate macroconidia) that arise from short conidiophores

    2.small, oval microconidia (2 to 4 μm) with smooth or slightly rough walls that are sessile or on short stalks
  28. Histoplasma capsulatum distribution? Pathogenesis?
    in soils w/ high nitrogen content, Especially areas contaminated w/ bird or bat droppings. Multiples in phagolysosome & lyse host cell.
  29. Acute pulmonary histoplasmosis
    Flulike illness w/ fever, chills, headache, cough, myalgias, chest pain. Mediastinal lymph node enlargement (can lead to mediastinal fibrosis) occurs in most pts. Usually resolves w/ supportive care, but can progress to acute respiratory distress syndrome
  30. Disseminated histoplasmosis
    most likely to affect pts w/ underlying disorders of cell-mediated immunity. Mucocutatneous lesions & hepatosplenomegaly are common.
  31. Coccidioides dimorphic? Acquired via? Infectious form?
    Dimorphic. Inhalation. Mold, infectious arthroconidia
  32. Coccidioides immitis location
    California, found in soil late summer/early fall (dusty season)
  33. Coccidioides posadasii location
    desert southwestern US, northern Mexico, and scattered areas of central and South America. Found in soil late summer/early fall (dusty season)
  34. Coccidioides primary disease
    Valley Fever: asymptomatic, self-limited flulike illness marked, Allergic rxn, Erythema nodosum (red nodules)
  35. Coccidioides secondary disease
    progressive pulmonary disease w/ nodules, cavitary disease. Lesions tend to calcify as they heal. Dissemination to skin, soft tissues, bones, joints, and meninges. More likely found in 3rd tri pregnancy & immunocompromised pts.
  36. Coccidioides Diagnosis via
    Nucleic acid hybridization
  37. Paracoccidioides brasiliensis dimorphic? Transmission route? Yeast form in tissue looks like...
    Dimorphic. Inhalation or traumatic inoculation. Pilot's wheel.
  38. Paracoccidioides brasiliensis common affects?
    Latin America (Brazil), children, exposure to soil, depressed cell-mediated immunity
  39. Paracoccidioidomycosis. Dissemination?
    South American blastomycosis. Dissemination frequently involves mucous membranes, skin, and lymph nodes
  40. Malassezia furfur (superficial) morphology? Transmission? Complications?
    Lipophilic yeast. Person to person transmission of infected keratinous material. Normal to skin flora. Hair follicle- folliculitis; yeast thrives in sebaceous environment
  41. Malassezia furfur Diagnosis

    KOH stain of skin scraping . Yeast clusters & short curved septate hyphae = “spaghetti and meatballs”. Coppery-orange fluorescence under UV, Calcofluor white, Culture (supplement with olive oil)
  42. Sporothrix schenckii (subcutaneous) infection dimorphic? Morphology?
    Dimorphic. Conidiophores arise at right angles from the thin septate hyphae and are usually solitary. Cigar-shaped yeast.
  43. Sporothrix schenckii transmission
    Trauma from thorns. Grows on bark of trees, shrubs, and garden plants. “rose-gardener” disease
  44. Pulmonary sporotrichosis (acquired via inhalation) associated with Alcoholics
    Sporothrix schenckii
  45. Trichophyton infection is...? Two forms?
    Cutaneous mycoses. microconidia are usually abundant. macroconidia absent or present in small numbers; when present, they are pencil-shaped and thin, with smooth walls
  46. Microsporum infection is...? morphology?
    Cutaneous mycoses. multicelled macroconidia with thick, rough walls
  47. Epidermophytom infection is...? Morphology?
    Cutaneous mycoses. microconidia absent; macroconidia typically club-shaped, with thin, smooth walls
  48. Trichomyton micro & macroconidia
  49. Microsporum micro & macroconidia
  50. Epidermophyton macroconidia
  51. Tinea corporis & its causative agent?
    Dermatophyte infection of smooth or glabrous skin. May be caused by any dermatophyte
  52. Tinea cruris & causative agent?
    Dermatophyte infection of groin. Trichophyton and Epidermophytom
  53. Tinea unguium & causative agent
    Dermatophyte infection of nails. Trichophyton
  54. Tinea capitis usually caused by? Ectothrix? Endothrix?
    Microsporum and Trichophyton. sheath of conidia formed on outside of hair shaft. Conidia formed w/in hair shaft
  55. Tineas favosa
    most serious; associated w/ tinea capitis, causes permanent hair loss. Contagious
  56. Tinea barbae commonly caused by
  57. Tinea pedis = Athlete's foot causative agent
    Trichophyton and Epidermophytom
  58. Dermatophyte: Diagnosis
    KOH preparation of skin or nail scrapings. Hyphae and arthroconidia in calcofluor white
  59. Cryptococcus neoformans morphology. Replication? Major virulence factor?
    Encapsulated, yeast-like. Budding. Capsule that inhibits phagocytosis & Downregulates Th1 responses
  60. Cryptococcus neoformans transmission
    In soil, pigeon droppings (inhalation). Opportunistic infection
  61. Cryptococcus neoformans Clinical Disease
    Acute pulmonary disease, Cutaneous Cryptococcosis, Life-threatening encephalitis or meningoencephalitis
  62. Aspergillus fumigatus morphology
    monomorphic. Branched, septate hyphae that produce conidial heads treelike pattern of branching. branches are dichotomous and usually arise at acute (∼45°) angles
  63. Aspergillus fumigatus
  64. Aspergillus fumigatus transmission
    Via inhalation. air, soil, and decaying matter.
  65. Aspergillus fumigatus : Clinical Disease
    Allergic Bronchopulmonary symptoms & Allergic sinusitis. Colonization of lower airway- obstructive bronchial aspergillosis

    –fungal ball, plugs composed of hyphal elements and mucinous material.

    –Lung cavities

    • –usually are asymptomatic; but can lead to pulmonary
    • hemorrhage- need surgical removal
  66. Invasive pulmonary or disseminated aspergillosis
    severely neutropenic and immunodeficient patients. necrosis and hemorrhage. Bronchial aspergillosis may cause wheezing, dyspnea, and hemoptysis. Cutaneous manifestations may occur
  67. Aspergillus fumigatus:Diagnosis
    Chest CT scans demonstrate “halo” signs, Area infiltrate surrounding nodular densities
  68. Candida albicans
  69. Candida morphology
    Oval yeastlike forms that produce buds or blastoconidia and chlamydospores. Produce pseudohyphae and true hyphae. Phenotypic switching may occur
  70. Candida hyphae & pseudohyphae
  71. Candida transmission
    Normal commensals of diseased skin and mucosal membranes of GI, UG, and respiratory tracts. Also found in environment. Nosocomial transmission. Primary source of infection: the patient
  72. Candida Virulence
    Surface molecules that permit adherence of the organism to other structures. Acid proteases and phospholipases. phenotypic switching
  73. Candida clinical manifestations
    • Oropharyngeal candidiasis & Hematogenous candidiasis (candida septicemia). Vulvovaginal candidiasis. Skin infections (pruritic rash with erythematous vesiculopustular lesions). GI candidiasis, Pulmonary candidiasis, Urinary tract candidiasis, Meningitis, Endocarditis, myocarditis
    • & pericarditis
  74. Candida diagnosis
    KOH, PAS, and GMS stains
  75. Pneumocystis jiroveci development forms
    • - trophozoite (trophic form), in which it often exists in clusters. Form inhaled; attach to alveoli
    • –The uninucleate sporozoite (precystic form)
    • - The cyst, which contains several intracystic bodies (spores)
  76. Pneumocystis jirovecii transmission
    Acquisition early in life; commonly found in the lungs of healthy individuals. Person-to-person spread
  77. Pneumocystis jirovecii: Clinical Disease
    Pneumocystosis. Interstitial pneumonitis & Extrapulmonary manifestations
  78. Pneumocystis
  79. Pneumocystis jirovecii: Diagnosis
    Giemsa & GMS stains. bronchoalveolar lavage (BAL) fluid in LM. Imaging.
  80. Histoplasma macrocanidia
  81. Coccidioides arthroconidia
  82. Blastomyces yeast
  83. Blastomyces yeast budding
  84. Histoplasma yeast
  85. Coccidoide spherule