Mycology Exam 1 – Flashcards
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| anthropophilic |
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| term applied to fungi that infect men only ( usually dermatophytes ) |
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| Aerial |
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| growing, forming or existing in the air |
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| arthoconidium |
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| asexual spore produced in a sac-like structure known as an ascus, after the union of two nuclei |
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| The type of speciment collected dictated by.. |
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| the site of infection. Collect with as little contamination as possible |
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| Specimens |
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| collect at the appropriate stage of infection with a good amount. must be collected in sterile containers. |
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| blood is sent when.. |
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| the patient is suspected of fungemia |
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| blood is collected.. |
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| aseptically and inocculated into broth bottles containing SPS (sodium polyanethol sulfonate) |
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| Other bodily fluids |
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| can also be used un fungus cultures. collected in tubes with heparin. |
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| Tissues can be tested for fungi cultures. true/false |
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| TRUE. |
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| Tissues must be |
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| grounded/minced using a mortar and pestle or tissue grinder. |
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| Urine is a common culture used to test for |
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| YEAST. first morning speciment is preferred in a sterile container. |
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| SPUTUM |
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| can be used for fungus cultures. another early morning specimen following teeth brushing. specimen from the lung, not saliva. you can crush the granules to see fungi. |
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| Exudates |
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| drainage. can be sent for culture |
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| CSF |
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| fungus culture. centrifuged prior to inoculation of the media. tests for things like meningitis. |
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| What is used to differenciate fungi? |
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| texture, topography,& color |
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| Colonial texture describes |
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| the height of the aerial specimen hyphae. |
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| cottony / woolly |
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| very high, dense aerial mycelium filling the whole petri dish. |
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| Another term for cottony is.. |
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| floccose |
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| Velvety texture |
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| low aerial mycelium which resembles a velvet sheath. raised by not high |
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| Granular / powdery texture |
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| flat & crumbly due to dense production of conidia. granular texture is rougher, like sugar. powdery is like flour. can be used interchangably. |
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| Glabrous Texture |
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| Waxy. smooth surface with no aerial mycelium. eg: YEAST |
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| Colonial Topography |
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| various designs of hills and valleys on fungal cultures. often masked by aerial hyphae. better to see on reverse side of slide. |
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| Rugose topography |
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| deep furrows irregularly radiating from the center. |
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| Umbonate Topography |
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| button like central elevation. may also have furrows. |
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| Verrucose Topography |
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| colonies show wrinkly surfaces. buds are star shaped/have feet |
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| Crateriform Topography |
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| central depression with a rasied edge. least commonly seen. |
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| Cerebriform Topography |
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| colonies look like the surface of the brain |
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| COLOR |
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| be specific - if there are concentric rings of different colors, observe all. Indicate colors on the front & reverse side. |
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| Dematiaceous |
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| colonies with dark olivegreen-brown / brown-black pigment. |
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| What stains darkly with or without dye? |
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| hyphae, conidiophores, and conidia. |
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| If a fungi is not dematiaceous, it is |
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| Hyaliine. meaning clear / colorless. possibly light pastel in color. |
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| Mycoses are fungal diseases classified based on |
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| tissue or body site invaded. |
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| Superficial Mycoses |
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| affect outermost layers of skin and hair. Little threatening pathology. cosmetic effects |
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| Cutaneous Mycoses |
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| destruction of keratin in nails, hair, and skin. doesnt invade deeper tissue. |
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| Subcutaneous Mycoses |
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| involves skin, muscle, and connective tissue immediately below the skin. |
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| Systemic Mycoses |
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| involve deep tissues, and organs. once the fungus reaches blood, it can spread everywhere. |
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| Organisms that contain true nuclei (eurkaryotes) and have no chlorophyll |
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| FUNGI |
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| Under the microscope, fungi are seen as either.. |
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| hyphae or yeast |
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| Aseptate Hyphae |
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| no cross walls, wide, ribbon like |
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| Septate Hyphae |
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| cross walls. thinner |
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| Vegetative Hyphae |
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| food absorbing portion of the hyphae called a mycelium. found under the surface of the colony |
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| Aerial Hyphae |
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| extend above the agar plate. can support conidia |
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| Reproductive structures.. |
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| conidia |
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| Favic Chandeliers |
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| look like deer antlers |
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| Nodular Organs |
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| knotted twisted hyphae |
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| Racquet Hyphae |
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| look like tennis racquets |
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| Spiral Hyphae |
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| may be flat, turn like a corkscrew, commonly seen in older cultures. |
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| Yeast |
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| oval/round. bud to form daughter cells |
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| Dimorphism |
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| two fungus stages |
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| Stage one |
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| room temperature. 25-30. Fungus grows mold. mold phase. |
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| Stage two |
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| Incubation. 35-37 degrees. Grows yeast. Tissue phase. |
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| Fungi can reproduce |
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| asexually and sexually |
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| asexual reproduction |
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| nuclear and cytoplasmic division (mitosis) |
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| sexual reproduction |
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| fusion of two nuclei to a zygote |
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| Conidium is a |
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| asexual reproductive structure that forms on the side or endof hyphae on a conidiophore. |
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| conidiphore is |
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| a specialized hyphal structure that sits like a stalk. conidia form on this. |
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| Blastoconidia |
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| also called blastophores. produced by budding. usually in yeast as candida. |
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| in some yeast, the blastoconidia can |
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| elongate to form pseudophyphae. they form constrictions at the point of attachment. |
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| Phialoconidia |
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| flask shaped. produce and extrude conidia without increasing or decreasing in length. EG: penicillium and aspergillus. |
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| Annelloconidia |
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| vase shaped. as each is produced and extruded, the tip tapers. aquires a ring of cell wall. saw tooth appearance. |
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| Macroconidia |
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| conversion of an entire hyphae into multicelled conidium. thin or thick. smooth or spiny. sessile, or on conidiophores. single or grouped. |
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| Microconidia |
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| produced the same as macro, the new conidium remains aseptate. one celled. round oval or club. sessile, supported alone, or clusters on a conidiophore. |
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| Chlamydoconidia |
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| thick walled. forms when there is unfavorable enviromental coniditions. stores food to survive. will germinate and produce conidia in better coniditions. |
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| Arthoconidia |
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| fragment from the hyphae through septation points. thick walled - barrel shaped / rectangular. |
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| Sporangiospores |
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| separate from conidia because they are only formed in aseptate fungi. conidia form in septate. formed by an internal cleavage of a sac called sporangium. |
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| sporangia |
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| supported on a base or columella and supported by a stalk - like sporaniophore |
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| Ascospores |
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| nucleus from a male (antheridium) crosses a bridge to a female cells (ascognium) once they form a zygote. it becomes an ascus. |
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| Ascus cells |
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| divide by meiosis to form 4 haploid cells which divide by mitosis, to form 8 nuclei. |
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| ascocarps |
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| medically important fungi completely enclosed and is called a perithecium. |
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| Basidiospores |
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| binucleate mycelium due to fusion of two hyphaes. terminal end is clubshaped . zygote produces 4 haploid nuclei. |
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| basidiospores protrude from the end of the basidium. |
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| the haploid nucleus travels into a basisiospore. |
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| zygospores |
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| compatible hyphaes. form an arm called a zygophore that extend toward eachother. when they fuse, they form a thick wall (zygosporangium) where the zygospore develops. |
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| Fungi Incubation |
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| some fungi require 3-4 weeks for growth |
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| Antifungal drugs |
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| toxic and require long periods of treatment. |
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| Saline Wet Mount |
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| can see budding yeast, pseudohyphae, and hyphae, and conidia. one drop of saline, one drop of specimen. |
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| Lactophenol Cotton Blue Wet Mount |
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| Original staining method for fungi. preferred stain for examination of mold colonies. |
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| In LPCB.. |
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| lactic acid - enhances penetration for the solution to the hyphae. then phenol- kills living cells. cotton blue- staining chitin in cell walls. Gylcerol - prevents dehydration. |
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| Potassium Hydroxide Prep (KOH) |
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| if specimen is skin nails or hair, cellular material may mask fungal. KOH dissolves keratin to make fungus more visible. In sputum, dissolves background making yeast more visible. |
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| KOH Potassium Hydroxide Prep |
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| one drop 10% KOH. heat slightly. pass through flame 2-3times. allow clear, 20 mins then observe. |
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| Gram Stain |
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| Fungi stain gram positive. most common on gram stain are yeast and pseudohyphaes. Hyphae are 2-3 times wider than gram pos. and yeast cells are 2-3 times larger than gram pos cocci. |
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| Acid Fast Stain |
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| fungus like Nocardia stain acid fast. appear to be red. mistaken for mycobacteria. possesses branching filaments. |
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| India Ink Prep |
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| used to see capsules around yeast. esp yeast cryptococcus neoformans in CSF specimens. dont stand out in black, but will be outlined in ink. |
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| Calcofluor White Stain |
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| bleaching agent. Taken up into the cell wall. chalkwhite or apple green fluorescence depending on the excitation wavelength when observed. |
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| Giemsa Stain |
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| hematology to study blood cells. mycology to search for yeast form histoplasma capslatum seen in blood smears or bonemarrow preps. |
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| primary media |
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| specific fungal media are inoculated to initially isolate any organisms. Tube media doesnt dry out as quickly as plates. |
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| selective media |
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| adds antibiotics |
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| some systemic fungi are fastidious therefore.. |
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| media contains blood for extra nutrients. |
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| Nonselective media |
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| most common is SDA. Sabourarud dextrose agar. ph 5.6 nutritionally poor (only has dectrose, peptone agar and water)inhibits bacteria growth but allows fungi to grow! |
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| Selective Media |
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| selective media must be paired with nonselective media. antimicrobial agents are directed at all microbes. |
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| Antibiotics in selective media |
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| is an antimicrobial agent used against bacteria. EG: chloramphenical and gentamicin. |
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| Anti-mycotics |
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| agents that kill or inhibit fungi |
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| most common anti-mycotic |
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| cyclohexamide. |
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| Cyclohexamide |
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| inhibits saprobic fungi (dont harm host - eat dead organisms) |
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| most fungi that infect men |
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| are resistant to cyclohexamide. |
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| (IMA) inhibitory mold agar. with chloramphenicol used |
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| when cyclohexamide is sensitive. |
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| Selective Media |
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| Brain heart infusion enriched with blood is useful with fastidious organisms. sheep blood too, esp for yeast. |
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| Media for Subcultures |
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| Potato dextrose agar (PDA)encourages organism to make reproductive structures. enhances pigment production. |
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| Birdseed Agar |
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| *niger seed agar used for rapid identification of cryptococcus neoformans. |
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| Neoformans |
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| produce phenol oxidase enzyme which results in production of melanin. dark maroon red to brown. |
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| Incubation Temperature |
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| Fungal incubates @ 30deg. room temp @ 25 is OKAY. but fungi multiply more slow at that temp. incubation @ 37 may INHIBIT fungi growth. |
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| yeast incubation |
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| 37 deg. |
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| Incubation |
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| Some fungi mature in 3-4 days, some take 3-4 weeks. All specimens should be incubated for one month before declared negative. |
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| Identify |
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| morphology may vary greatly among strains |
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| MOLDS |
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| final identification done with microscopic morphology analysis |
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| yeast & fungus like bacteria |
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| biochemical tests are the primary basis for identification |
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| Slide culture Method |
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| used when not enough info received to identify using LPCB. uses PDA PFA media. reproductive structures of fungus are enhanced by growth on these medias. |
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| Slide CUlture Media |
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| cut a piece of agar from the petri dish. inoculate the sides of the block. incubate in a moist chamber to not dry out, then place on a slide with LPCB. |
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| In vitro hair penetration test |
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| identify fungi called dermatophytes. uses sterile hair with a source of yeast extract for nutrition. hair is from young child, preferably light in color. incubate @ RT for 4 weeks. place on slide with LPCB. |
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| In vitro Hair penetration test results |
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| Positive: wedge shaped or conical perforations into the hair shaft. Negative: no wedge shape. Test is positive for trichophyton mentagrophytes Negative for: trichophyton rubrum |
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| Germ Tube Test |
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| uses pooled human serum like protein. 0.5ml placed in tube with light suspension of the yeast. incubate at 35-37 for no longer than 3 hrs |
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| Germ Tubes |
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| are the begining of true hyphae and appear as filaments. not constricted. |
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| Corn Meal Agar with Tween 80 |
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| without dextrose is recommended for the cultivation of chlamydospore-bearing candida albicans. |
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| Chlamydospre production is enhanced with |
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| addition of tween 80. The candida species are inoculated onto corn meal agar with tween 80 using the Dalmau technique. |
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| LAST ONE |
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| tween 80 is like a detergent. Albicans are most often found in yeast! |
