Farah Salim. No Downloads. Views Total views. Actions Shares. Embeds 0 No embeds. No notes for slide. Mycology Just the basics — meant for board review or brief study of this fascinating area of microbiology! Mycology 2. What effect does Cycloheximide have when added to media? There are manual and automated biochemical reactions capable of identifying most yeast species. Processing of Fungal Cultures - stepwise 9. Lactophenol cotton blue [LCB] adhesive tape preparations are the standard method used for mold identification. The LCB mounting medium consists of phenol lactic acid, glycerol and aniline cotton blue dye.
Clear adhesive tape touches a mold colony, picking up fungal hyphae and pressed into one drop of LCB If LCB prep is not able to identify a mold 16sRNA sequencing can be used to identify problematic molds in reference laboratories. Mold Identification Can only reliably detect yeast by Gram stain. Yeast cells stain blue [Gram positive]. Examine for budding cells to confirm that it is a yeast cell and not an artifact. Examination on oil immersion lens. You can also detect pseudohyphae on Gram stain. Mold can be difficult to identify on a Gram stain. KOH dissolves keratin found in cell material and frees hyphae from the cell KOH exams can be difficult to interpret!
KOH — potassium hydroxide prep Yeast, pseudohyphae, and mycelial fungi will bind with the Calcofluor white stain. Prep is interpreted using a fluorescence microscope. Sensitivity and specificity is improved over the KOH preparation.
Calcofluor white stain Specificity is improved if you look for budding yeast cells. India Ink Examine the hyphae for presence of septations in the hyphae, broad or more narrow width and angle of branching. Examine the size and budding pattern of observed yeast. We will observe on later slides these criteria can assist in identification. Examination of fungi in fixed tissue Stain-Cryptococcus neoformans polysaccharide capsule stains pink Mucicarmine [Mucin] stain Hematoxylin and Eosin Stain The Dimorphic Fungi Important pathogens with some unique characteristics What does Dimorphic mean?
The yeast of Histoplasma capsulatum prefer to be intracellular and inhabit Macrophages.
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Yeast are small 2 — 4 um, regular in size, and oval to round. Yeast do not have a capsule, this is just a staining artifact. Microscopic exam: Tuberculate [projections] macroconidia is the structure used for ID.
Microconidia are the infectious particle. Appearance in culture at 30 degrees C Leishmania species Note small round kinetoplast next to nucleus Toxoplasma Histoplasma capsulatum Beware of look alike organisms in tissue specimens!!
H capsulatum var duboisii yeast cells are 8 — 10 uM in size, which is 2X the size of regular Histoplasma capsulatum yeast cells. Unusual variant of H.
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Blastomyces culture at 37 degrees C Blastomyces dermatitidis histopathology Mixed pyogenic and granulomatous inflammation is observed in tissue with Broad based budding yeast cells The two species are located in different endemic regions, but produce the same disease process Dissemination to the central nervous system is difficult to cure and has a high fatality rate. The clear spaces are dead arthroconidia. Coccidioides Malbranchea Barrel shaped alternating arthroconidia are produced in cultures grown at both 30 and 35 C.
There is no yeast phase for C. This is the second form of Cocci. No yeast cells are produced in tissue for this fungus. Development of Cocci spherules from the inhalation of Arthroconidia from nature Also R. Oral or nasal mass lesions of Rhinosporidium seeberi Coccidioides spherules Cocci is not the only spherule forming organism! Pneumonia 2. Disseminated infection 3. Extrapulmonary lesions on the face and oral mucosa Starts as one ulcerative lesion and then chains Up the lymphatics — can involve lymph nodes and bone Daisy like spore arrangement Sporothrix schenckii Green colony with red diffusable pigment Uncommon dimorphic fungus The only species of Penicillium that is dimorphic Causes skin lesions in tropics and Pneumonia in immune suppressed Penicillium marneffei Penicillium marneffei yeast like cells in tissue Subcutaneous Fungal Infections Very unique structures in tissue!
Lesions lead to swollen extremities 2. Draining sinuses 3. Swollen extremity and draining sinus with sulfur granules Sulfur Granule Mycetoma Actinomycotic mycetoma — caused by higher bacteria species 2. Gram stain as filamentous Gram positive bacilli — can be poorly staining and appear speckled. Nocardia are positive [red] on the Modified Kinyoun stain. Acta Mycologia. Acta Mycologia Sinica.
African Journal of Mycology and Biotechnology. L'Amateur de Champignons. Annales Mycologici. Australasian Mycologist. Beihefte zur Zeitschrift fur Mykologie. The Bibliography of Systematic Mycology. Bulletin of the British Mycological Society.
British Mycological Society. Cryptogamie . Documents Mycologiques. Experimental Mycology. Field Mycology. The Forayer. Association of British Fungus Groups. Fungal Biology and Biotechnology. Fungal Biology Reviews.
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Fungal Ecology. Fungal Genetics and Biology. Fungal Science. International Journal of Mycology and Lichenology. International Journal of Medicinal Mushrooms.
Journal of Fungi . Journal of Mycology. Journal of Mycopathological Research. The Lichenologist. Acta Mycologica Hungarica. Taylor and Francis . Micologia e Vegetazione Mediterranea. Abruzzo ; G. Gruppo Ecologico Micologico Abruzzese. Micologia Italiana.