Micro Prax 1- Mycology

8/4/2019 Micro Prax 1- Mycology

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Micro Prax 1- Mycology

Thanks to Renn, Lilia, Kate and Iami for the pictures

Some pictures are from past prax reviewer (batch 2013)Thank you!

Some I got from the internet thank you google!!!

Go Batch 2014!!!!


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Exercise 10- KOH Mount

Potassium hydroxide (KOH) mount

a rapid method for the demonstration of fungal forms in clinical material

facilitates the clearing of specimens for enhanced microscopic observationwithout altering the fungal elements

partially digests proteinaceous components (e.g. host epithelial cells) that are

collected along with the fungi leaves the polysaccharide-containing cell walls intact

***rapid because the specimen placed in a drop of KOH will dissolve at a faster ratethan the fungi

***proteinaceous components are partially digested by the alkali, leaving the cell

walls intact***the chitinous cell walls of fungi protects fungal elements from disintegration

10% KOH- for skin scrapings

20% KOH- for nail scrapings


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Upon potassium hydroxide (KOH)

examination, hyphae are visible and

grow into strands within clumps of

keratinocytes.

Thick-walled spores frequently occur

in grapelike clumps. Individual spores and short stubby

hyphae float in the clear areas

between clumps of keratinocytes.

Many of the short hyphae are

dystrophic.

hyphae

spores


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KOH Mount Skin Scrapings

Hyphal filaments Spores


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Ptyriasis Versicolor

Basidiomycota

Infectious forms: short

hyphae and yeast like

cells Can be visualized by

woods lamp

Culture not done

Scaly patches of

variable color

Mostly endogenous

Lipophilic

Also called as tinea

versicolor, tinea alba

and tinea flava Spread from person to

person


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Exercise 11- Microscopic Morphology

of Fungal CultureAccurate identification of filamentous fungi is based on the microscopic examinationof sporulating parts of a colony, since each species has a characteristic morphologyand arrangement of its spores and fruiting bodies.

Tease Mount Preparation

- traditional procedure used by most laboratories

Principle: To demonstrate conidia or other reproductive structures or morphologicalforms which might give information toward the identification of theorganism.

Slide culture or van Tieghem cell

- best method for preserving and observing the actual structure of a fungus

Principle: In an undisturbed state, important microscopic structures and morphologicdetails are demonstrated

Lactophenol Cotton Blue (LPCB)

- for very quick evaluation of fungal structures

Principles: It has 3 components: lactic acid which preserves fungal structures, cottonblue (an acid dye) which stains the chitin present in the cell walls, and phenol

which kills any live organisms suspended in the stain


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Candida albicans


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Tease Preparation

Candida albicans

Ovoid yeast cells

Note: budding yeast cells (arrow)


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Below:

Candida albicans in its hyphal form

Budding yeast (arrows)


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Phylum: Ascomycota

Representative Genus:Candida albicans

Brief Description:Opaque colored colonies with pasty consistencyAppear as budding yeast cells, psudohyphae, or acombination of both

Reproduction: no sexualAsexual spores chlamydiospores

Hyphae:pseudohyphae occurring in elongated chains


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Epidermophyton floccosum


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Tease Preparation

Epidermophyton floccosum

Smooth, thin-walled macroconidia

which are often produced in clusters

growing directly from the hyphae

Macroconidia


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Numerous chlamydoconidia are

formed in older cultures.

No microconidia are formed.

Chlamydoconidia

Hyphae


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Phylum: Deuteromycota Representative Genus: Epidermophyton floccosum Brief Description:

Colonies are olive green or khaki-colored with powdery surface that become folded with floccose patches as cultureages. Reverse is orange to brownish at times with yellow border

Reproduction: no sexual reproduction

Hyphae: septate Macroconidia:

best seen in young culture- smooth, club-shaped with rounded ends, contain 2-6 cells, found singly or in characteristic

clusters; transform to chlamydiospores Microconidia: absent


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Trichophyton mentagrophyte

Mi idi


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Trichophyton mentagrophyte

Brief Description: Colonies vary greatly. Surface may be buff

and powdery or white and downy;powdery form exhibit concentric andradiate margin

Reproduction: no sexual reproduction, only in anamorph

stage

Hyphae

Microconidia


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Phylum: Deuteromycota

Representative Genus/Species:

Trichophyton mentagrophytes

Hyphae:

coiled spiral hyphae maybe present

Macroconidia: Usually rare, not always present,cigar shaped thin-walled, narrowly attached tothe hyphae and contain 1-6 cells

Microconidia: numeous, borne in clusters alongthe hyphae


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Microsporum gypseum

Mi


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Microsporum gypseum

Brief Description: Colonies re flat and spreading with

powdery to granular surface, irregularly

bifringed border; buff at first, thenbecomes tan to cinnamon brown

Reproduction: No sexual reproduction

Macroconidia

Hyphae


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Representative Genus: Microsporum gypseum

Hyphae: With septate

Macroconidia: numerous, symmetric with roundedends and having no more than 6 cells

Microconidia: club-shaped and usually seenamong hyphae


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Aspergillus sp.


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Slide Culture Preparation

Aspergillus sp.Vesicle

Conidiophore

Hyphae


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Swollen Vesicle

Conidiophore

Septated

Hyphae


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Phylum: Ascomycota

Representative Genus: Aspergillus sp.

Brief Description:

Smokey green color colonies,

Reproduction:

No sexual reproduction

Hyphae:

Wide, septated,dichotomously branchingwith conidial heads

Classification Accg. To Habitat:

Ubiquitous (soil, plants,organic debris)


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Aspergillosis

Infectious form:

Conidia

Tissue form: Hyphae

Most common species:

A. Fumigatus

Natural reservoir:

Soil and air

Occurs as:

Allergic form

Colonizing form

Disseminated

Mycotoxicosis

In culture:

Conidiophore with

swollen vesicle, rows of

phialides bearing radial

chains


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Penicillium sp.


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Penicillium sp.

Slide Culture Preparation


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Conidiophore

Hyphae

Metullae

Conidia

Metullae

Conidia


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Metullae

Conidiophore

Conidia

Hyphae


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Representative Genus:Penicillium marneffei

Brief Description:For P. marneffei- the only species that is dimorphicFlat, powdery to velvety, and tan to reddish yellow colonies

Reproduction:no sexual reproduction

Hyphae: septate


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Penicillium

Produce red pigments

Reproduction:transverse fission/schizogony

Unknown habitat

Infectious form:

Conidia

KOH: small ovoid yeastcells with transverseseptum

Culture RT:conidiophores (flaskshape) branch intometullae with phialides

Culture at 37C- Roundyeast cells with crosswalls


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Micro Prax 1- Mycology