Mycology Ciulla

Moulds

Multicellular fungi

Yeasts

Single-cell fungi

Mycosis

Fungal infection

Systemic mycosis

Multiorgan infection caused by fungi

Opportunistic mycosis

Fungal disease that occur primarily in

immunocompromised patients

Dimorphic fungi

Fungi that show both a nonmould (e.g., yeast) and mould

phase

Saprobe

Organism capable of living on decaying organic material

Hyphae

are long, branching filaments that come together to form the

mycelium

Septate hyphae

cellular separation or cross-walls, range in diameter from 3-6 um

Sparsely septate (Aseptate)

contain few if any cellular separations, range in diameter from 5 to 15 urn.

Coenocytic

hyphae lacking cross-walls

Pseudohyphae

chain of cells formed by budding that resemble true hyphae

Vegetative hyphae

function in food absorption and are the portion, extends below the agar surface or nutrient substrate.

Aerial hyphae

function is to support reproductive structures called conidia, extend above the agar.

Conidia

sporelike asexual reproductive structures

Microconidia

single-celled, small conidia.

Macroconidia

multicellular, large conidia.

Arthroconidia

conidia resulting from the fragmentation of hyphae into individual cells

Blastoconidia

Conidia that form as the result of budding

Chlamydoconidia

terminal cells in the hyphae that enlarge and have thick walls.

Poroconidia

Conidia formed by being pushed through a small pore in the parent cell

Phialoconidia

Tube-shaped conidia that can be branched

Annelloconidia

vase-shaped conidia

Ascospores

Spores contained in a saclike structure

Basidiospores

Spores contained in a club-shaped structure

Oospores

Spores resulting from the fusion of cells from two different hyphae

Zygospores

Spores resulting from the fusion of two identical hyphae

Sabouraud dextrose agar (SDA)

General-purpose, nutritionally poor medium mildly selective for fungi, no longer commonly used;

Sabouraud-brain heart infusion agar (SABHI)

• nonselective medium for isolation of all fungi

• Contains dextrose, peptone, and brain heart infusion

Brain heart infusion agar with blood (BHIB)

Used to grow most fungi, especially those from sterile body sites

Selective agars

contain various antimicrobial agents that will enhance the growth of specific fungal pathogens and will inhibit bacteria and other undesired growth.

Inhibitory mould agar (IMA)

used to grow most fungal pathogens; it is especially formulated to recover the cyclohexamide-sensitive Cryptococcus.

Dermatophye test medium (DTM)

Used to isolate the dermatophytes

Differential agars

used to enhance pigment development, conidia production, and mould-to-yeast phase transition.

Potato dextrose agar (PDA)

Enhances pigment development of Trichophyton rubrum

Bird seed (niger seed) & caffeic acid agars

selective and differential media used to grow C. neoformans.

Cornmeal agar with Tween 80

Used to differentiate Candida spp.

Agars containing rice, casein, and other nutrients

used to differentiate Trichophyton spp.

Tease mount method

dissecting needle is used to pull apart a fungal colony, which is placed on a slide.

Cellophane tape method

used to transfer aerial hyphae from the colony to a microscope slide for examination.

slide culture method

uses a block of agar overlaid with a cover slip. Fungal colonies are grown on the side of the agar block.

Saline wet mount

most commonly applicable for vaginal secretions to diagnose vaginitis

Lactophenol cotton blue wet mount

used to stain and preserve fungal elements in culture isolates

Potassium hydroxide (KOH)

used to dissolve nonfungal materials in skin, nail, and hair samples.

Gram stain

used to view yeasts.

India ink

used to reveal capsules surrounding C. neoformans found in cerebrospinal fluid (CSF)

Calcofluor white stain

a fluorochrome that stains chitin found in the cell wall of fungi

C. albicans

most common yeast isolate and is the causative agent of candidiasis

C. albicans

normal flora of the mucous membranes lining the respiratory, gastrointestinal, and female genital tracts.

endogenous

Most adult infections of candida albicans are

exogenous

infants acquire infections from their mothers

Types of candidiasis

• oral cavity

Thrush

Types of candidiasis

• vagina

Vulvovaginitis

Types of candidiasis

• nail infections

Onychomycosis

Types of candidiasis

• cuticle infections

Paronychomycosis

C. albicans

can also cause systemic infections, including meningitis, UTIs, and heart and lung infections.

sheep blood, chocolate, and eosin-methylene blue agars

C. albicans grows on most fungal media as well as _____

C. krusei

Urease positive Candida spp.

positive germ tube

A ________ can be a presumptive identification of C. albicans

Cryptococcus neoformans

can produce a mild to moderate pulmonary infection, can lead to systemic infections and meningitis.

Cryptococcosis

is also associated with prostate and tissue infections

C. neoformans

acquired by contact with bat, pigeon, or other bird droppings, in addition to contaminated vegetables, fruit, and milk.

C. neoformans

On Gram stain the yeasts appear in spherical form and are not of uniform size

Trichosporon

White Piedra

Rhodotorula spp.

are found in moist environments such as on shower curtains and toothbrushes.

Geotrichum candidum

forms true hyphae with rectangular arthroconidia

Aspergillus fumigatus

most common cause of aspergillosis

A. niger

important cause of otomycosis

Aspergillus spp.

have septate hyaline hyphae

A. niger

colonies are yellow to black with a yellow reverse

A.flavus

colonies are green to brown with red-brown reverse

A. terreus

colonies are green to yellow with yellow reverse

A. clavatus

colonies are blue to green with white reverse

A.fumigatus

colonies are green to gray with tan reverse

Absidia spp

exhibit branching sporangiophores between the rhizoid (rootlike hyphae).

Mucor spp

Single or branching sporangiophores are present, but rhizoids are absent

Rhizopus spp

produce unbranched sporangiophores that arise opposite rhizoids.

Fusarium spp

associated with a variety of clinical presentations, including mycetomas, keratitis, and systemic infections.

Superficial mycoses

infections that involve the outer epithelial layers of the skin and top layers of the hair and nails

Cutaneous mycoses

involve deeper layers of the skin and more tissue.

Dermatophyte

term used to group the various fungi that cause infections (dermatophytoses) of the skin, hair, and nails.

keratinophilic

dermatophytes are

Trichophyton

Infects nails, hair, and skin

Epidermophyton

Infects skin and nails

Microsporum

Infects hair and skin

Tinea pedis

• infection between spaces of the toes

• athlete’s foot

Tinea corporis

• infection of smooth skin

• ringworm

Tinea unguium

• infection of nails

• onychomycosis

Tinea capitis

• infection of the scalp

Tinea barbae

• infection of bear hair

• barber’s itch

Tinea cruris

• infection of the groin

• jock itch

Tinea (pityriasis) versicolor

Malassezia furfur

Tinea nigra

Hortaea werneckii

Black piedra

Piedra hortaea

White piedra

Trichosporon ovoides

Chromoblastomycosis

• sclerotic bodies (copper-colored fungal cells)

• Fonsecaea pedrosoi

• Phialopora

• Cladosporium

Sporothrix schenckii

• Rose gardener's disease

• Cigar shaped

• dimorphic fungi

Dimorphic Fungi

• Blastomyces dermatitidis

• Coccidioides immitis

• Histoplasma capsulatum

• Paracoccidioides brasilliensis

• Sporothrix schenckii

Blastomyces dermatitidis

Large, round, thick-walled, budding yeasts with broad-based blastoconidia

Coccidioides immitis

• Joaquin Valley fever

• barrel-shaped arthroconidia