Tinea

Affects what area?

What type of infection?

Is this term specific?

affects the skin-
"dermatophyte"

dermato: skin    phyte: to grow

ringworm (beard, face, scalp, body, groin/"jock itch", feet/"athletes foot" and nails)

Tinea is simply a blanket term for fungus of the skin/hair

Microsporum

Dermatophyte of the skin and hair.

Macroconidia: Numerous, thick-walled fusiform or spindle shaped, multiseptate, with a rough surface.

Microconidia: few or absent, with a small, club shape.

Microsporum Canis

Zoophilic, common cause of ringworm in dogs and cats.

Fluoresces with Wood's light.

Microsporum gypseum

Geophilic, loves the soil

dermatophyte

Microsporum audouinii

Primary cause of tinea capitis in school children.

dermatophyte

Trichophyton

A dermatophyte that infects the hair, skin and nails.

Trichophyton

Involves both endothrix and ectothrix infections.  

A form of a dermatophyte infection.

Macroconidia: Few, smooth, thin walled, club-shaped.

Microconidia: Few to Numerous round to club shaped in

grape-like clusters.

Epidermophyton

A dermatophyte infection involving the skin and nails.  

Macroconidia: Numerous, club-shaped, smooth-walled

with 2 to 4 cells.

Microcondia: NONE.

Chlamydoconidia are numerous.

Dimorphic

Fungal organisms capable of both the mold phase and the yeast phase.

Yeast Phase

Growth at body temperature, 35-37°C.

Mold Phase

Fungal growth at 25°C.

Blastomyces

dermatitidis

Is one of the systemic mycoses.

Causes a respiratory infection that sometimes spreads to the skin and bones.  

Transmitted through inhalation of conidia or hyphae.

Dimorphic.

In the mold phase, it looks like little lollipops.

Coccidiodes immitis

MOST INFECTIOUS OF ALL FUNGI.

Is one of the systemic mycoses.

In infection, 60% have an asymptomatic, self-limiting respiratory infection.  Can disseminate to organs, bone, skin, and lymph nodes.

The infection can become an epidemic.

Inhalation of arthrospores in soil or enviroment.

Septate hyphae with arthroconidia having a

barrel shape.

Histoplasma

capsulatum

One of the systemic mycoses.

Primarily a lung infection, often confused with TB.

Can disseminate to the lymph nodes, bone marrow, liver and spleen and 95% are asymptomatic.

Severity of disease related to size of inoculum.

Organism is an intracellular parasite and is found upon direct examination within the host's mononuclear cells.

Dimorphic tuberculate macroconidia.

Paracoccidiododes

brasiliensis

One of the dimorphic, systemic mycoses.

Chronic granulamatous infection that begins in the lungs, lymphatics, skin and mucous membranes and can spread to the liver and spleen.

"Mariner's Wheel" shaped yeast buds with

Chlamydoconidia in mold form.

Penicillium marneffei

An opportunistic, dimorphic fungus.

Most often found in the immunocompromised.

Focal cutaneous or mucocutaneous infection with possible dissemination and fatality.

Direct examination yields small, yeastlike cells with internal crosswalls and no budding.

Thermal conversion to yeast form may be necessary for ID. 

Sporothrix shenckii

Dimorphic, subcutaneous mycoses.

Sporotrichosis.

"Rose Gardner's Disease" because it can be aquired from pricking the finger from a thorny plant, or bales of hay.

Fast growing conidiophores, with a flowerette apearence. Delicate, branching, septate hyphae with the conidium attached via a denticle.

Sporotrichosis

A chronic subcutaneous infection with rare dissemination.

Is the disease form of Sporothrix shenckii.

DOES NOT involve the hair. (trich/o)

General Characteristics of Fungi

-Non Motile

-Eukaryotic

-True cell wall containing chitin

-Cell membrane contains ergosterol

-Lacks chlorophyll

-Reproduce with spores

-Heterotrophs

Heterotroph

An organism that uses organic carbon for growth by consuming other organisms.

Autotroph

An organism that can use direct sources of energy, like sunlight, to produce organic substrates like carbon dioxide.

ie: plants

Fungal cell walls contain...?

Chitin.

Fungal cell membranes contain...?

Ergosterol, as opposed to cholesterol.

Mycelium

A mass of hyphae

Hyphae

Microscopic tubular structures.

Vegetative Portion

Grows on the substrate and absorbs water and nutrients.

On a diagram, it would be the lower portion.

Aerial Portion

Contains the fruiting bodies that produce reproductive structures called spores (or conidia).

On a diagram, it would be the upper portion.

Zygospores

One of the three forms of sexual reproduction.

Produced from the fusion of the tips of two compatible hyphae.

Basidiospores

One of the three forms of sexual reproduction.

Formed at the end of a club shaped cell.

Ascospores

One of the three forms of sexual reproduction.

A sac like structure contains the haploid cells that can be found inside the sac, or released to the outside.

Imperfect Fungi

Fungi capable of asexual spore production.

Deuteromycota

Phyla of fungi only capable of asexual spore production.

-"mycota"

Phylum

-"mycetes"

Class

Two main forms of asexual reproduction:

Sporangiophores

Conidia

Sporangiospores

Produced by the phyla Zygomycota

Conidia

Produced by the phyla:

Ascomycota

Basidiomycota

Deuteromycota

Conidiogenesis

Asexual reproduction with a stalk like structure extending from the hyphae and terminating in a swollen vessicle.

-metullae

-phialides

-conidia (single or in chains)

Conidiogenesis

Aspergillus

Conidiophore with swollen vessicle.  

Often refered to as a "fungus ball infection".

Numerous species including niger, flavus and clavatus.

Penicillium

Conidiophore with branching.

Brush like conidia at the end of penicillus.

Dematiaceous

Molds

A general term meaning dark-colored.

Generally non-pathogenic, except for the black mold.

Can be superficial or subcutaneous.

Mycetoma

A subcutaneous dematiaceous infection involving the bone structure and other subcutaneous tissues.

Involves abscesses, draining sinuses and granulomatous pus.

Chromoblastomycoses

A localized infection of the underlying tissue that is characterized by chronic, hard tumor-like lesions (cauliflower like) on the feet and lower legs.

Rhizoids

Tree-root like growth structure.

Yeasts

Most frequently isolated fungi in the clinical laboratory.

India Ink

Stain used to ID yeasts under the microscope.

Candida albicans

Most frequently isolated yeast.  

Normal flora of the GI tract mucocutaneous areas.

Infections include Thrush, diaper rash, vulvovaginitis and onychomycosis.  Can become systemic.

Exhibits the unusual characteristic of being BOTH a yeast and a mold at 37°C and a yeast at 25°C.

Only yeast to produce a germ tube.

Cryptococcus

neoformans

A round, encapsulated yeast common in pigeon, bat or bird droppings.

Direct microscopic exam shows a very striking irregular sized, spherical yeast cell, often with budding.

Cryptococcus

neoformans