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Mycology – Introduction. Student Lab Division of Medical Technology Carol Larson MSEd, MT(ASCP). Mycoses. Superficial Subcutaneous Systemic Opportunistic. Characteristics of fungi. Eukaryotic Growth requirements Forms Mold Yeast. Hyphae. Septate. Aseptate. Hyphae. Hyaline.
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Mycology –Introduction Student Lab Division of Medical Technology Carol Larson MSEd, MT(ASCP)
Mycoses • Superficial • Subcutaneous • Systemic • Opportunistic
Characteristics of fungi • Eukaryotic • Growth requirements • Forms • Mold • Yeast
Hyphae • Septate • Aseptate
Hyphae • Hyaline • Dematiaceous
Mycelium • Mass of branching intertwined hyphae • Vegetative • Aerial • Fertile
Vegetative types • Favic chandeliers • Nodular organs • Racquet hyphae • Spiral hyphae
Reproduction • Identify fungi by: • Morphology of reproductive structures • Spores from vegetative mycelium or aerial fruiting bodies
Asexual Reproduction • Conidia • Conidiophore • Arthroconidia
Asexual Reproduction • Blastoconidia • Pseudohyphae • Chlamydoconidia • Chlamydospores
Asexual Reproduction • Macroconidia • Microconidia • Phialoconidia • Phialide
Asexual Reproduction • Annelloconidia • Annellide • Sporangiospores • Sporangium • Sporangiophore
Sexual Reproduction • Perfect Fungi – has a sexual stage • Fungi Imperfecti – no know sexual stage • Spores
Sexual Reproduction • Ascospores • Ascus • Ascocarp • Basidiospores • Zygospores
In review … • Mycoses – fungal diseases • Characteristics of fungi • Growth requirements • Forms (mold, yeast) • Structures • Reproduction • Asexual • Sexual
Fungal Culture Process • Specimen collection and transportation • Direct examination of specimen • Selection and inoculation of media • Evaluation of fungal growth • Serological testing • Antifungal susceptibility testing
Specimen Collection • Specimen types • Collect from area most likely infected • Use sterile technique • Keep specimen moist • Label container properly • Transport right away • Process right away
Direct Examination • Provides preliminary report • Guides MD in treatment of patient • Observe yeast phase of dimorphic • Gives clues to id causative agent • Inoculate special media • May require more than one direct examination method
Direct Examination • Saline wet mount • Lactophenol cotton blue wet mount • 10% KOH preparation • Gram stain • Acid fast stain • India ink stain
Direct Examination • Calcofluor white stain • Wright’s stain • Gomori Methenamine Silver stain • Periodic Acid Schiff stain
Specimen Processing • Safety • Tube media preferred over plate media • Work in safety hood • Wear gloves and lab coat • Autoclave specimens and media • Disinfect work area daily
Specimen Processing • Primary isolation media • Goal: isolate potential pathogens • Use non-selective and selective media • Proper ingredients • Incubation temperature • Incubation time • Incubation atmosphere
Non-selective Media • Sabouraud dextrose agar • Brain heart infusion (BHI) with/without 5% blood and 1% glucose
Selective Media • Mycosel agar • Inhibitory mold agar • Dermatophyte test medium
Subculture / Identification Media • Neutral Sabouraud dextrose agar (Emmon’s) • Cornmeal-Tween 80 agar • Niger seed agar (Birdseed agar) • Tween 80 / Oxgall / caffeic acid agar • Potato dextrose agar
Examination of Culture Growth • Potential pathogens • Slow growers • Growth on Mycosel • Color: dull buff, brown, mousy gray • Dimorphic
Examination of Culture Growth • Growth rate • Rapid growers: 1-5 days • Intermediate growers: 6-10 days • Slow growers: >10 days
Colony Morphology –Appearance • Rugose • Umbonate • Verrucose • Flat
Colony Morphology –Texture • Cottony • Glabrous • Granular • Velvety
Colony Morphology –Pigmentation • Surface • Reverse
Microscopic Morphology • Definitive means of identification • Evaluate: • Shape • Method of production • Arrangement of conidia/spores • Size and color of hyphae
Microscopic Techniques • Tease mount • Scotch tape preparation • Slide culture
Serological Diagnosis • Immunodiffusion • Complement fixation • EIA • Latex agglutination
Antifungal Susceptibility • Determine appropriateness • Standardization of testing • Methods • Predictability in vivo • Antifungal agents
In Summary … • Specimen collection and transport • Specimen processing and culture • Direct examination of specimen • Examination of culture • Serological testing • Antifungal susceptibility