Fungus and Molds

Tinea nigra

Skin infection, caused by H. werneckii

Black piedra

Hair and scalp infection caused by P. hortae

Mycetoma

Mostly found in tropical and subtropical regions.

Chronic granulomatous infection involving the lower extremities.

Mycetoma

Chromoblastomycosis

a chronic fungal infection involving skin and subcutaneous tissue caused by several species of dematiaceous fungi (cauliflower or tumor-like lesions)

Alternaria

Horizontal and longitudinal septa

Bipolaris

Bent conidiophores, germ tubes at one or both ends.

Curvularia

Conidia, curved, swollen central cell, multicelled

Exophiala

Elongated conidiophore with tapered tip

Pneumocystis pneumonia (PCP)

Caused by Pneumocystis jirovecii

Pneumocystis jirovecii symptoms

nonproductive cough, low grade fever, dyspnea, chest tightness, night sweats

Lacazia loboi

organism found in soil, on vegetation and in aquatic animals

Lobomycosis

caused by Lacazia loboi

Pythium insidiosum

funguslike, aquatic oomycete organism

Lagenidium spp.

invasive skin, subcutaneous and arterial infections, can cause inrections in cornea, GI tract, and extermities (Lagenidiosis)

Rhinosporidium seeberi

organism found in aquatic environments and resistant spores are present in terrestrial environments

Rhinosporidiosis

painless polyps formed on the mucosa of the nose, eye, larynx, genitalia and rectum

Resistant to anti-fungals

P. insidiosum and R. seeberi

Blastoconidia

consists of buds coming off the parent cell

95% of yeast infections are attributed to

Candida spp.

Cryptococcus spp.

Important causes of meningitis, pulmonary disease, and septicemia.

Malassezia furfur

Causative agent of tinea versicolor

Tinea versicolor

scaly lesions on the skin, dark on light-skinned persons, light on dark-skinned persons.

India Ink

used to visualize Cryptococcus neoformans

Malassezia spp.

"Spaghetti and meatballs" appearance on microscopy

Itraconazole

used to treat systemic fungal pathogens

Fluconazole

treat Candidia spp., and cryptococcus neoformans.

Ketoconazole

treat mild cases of paracoccidioidomycosis

Voriconazole

active against Fusarium and fluconazole-resistant yeasts

Posaconazole

Effective against dermatophytes

Isavuconazole

treatment of Aspergillosis

Selenium sulfide

Shampoo for Malassezia furfur

Saprophytic

Fungi that get their energy from decaying organic matter

Dimorphic

occurring or existing in two different forms (yeast and mold forms)

Teleomorph

sexual stage

Anamorph

asexual stage

Synanomorph

Different asexual forms in the same fungus

Superficial Cutaneous Mycoses

involve hair, skin or nails without direct invasion of deep tissue

Subcutaneous Mycoses

Infections are confined to subcutaneous tissue without dissemination

Systemic Mycoses

Infections often involve the lungs but can disseminate to any organ.

Opportunistic Mycoses

Infections occurring in immunocompromised individuals.

What is the incubation temperature for yeasts?

30 Degrees C

What is the minimum incubation duration for yeasts?

21 to 30 days

What is the humidity range for yeast incubation?

40 - 50%

How often should yeasts be examined during incubation?

At least 3 times a week

Calcofluor White Stain

A fluorochrome that stains chitin found in the cell wall of fungi. Viewed under UV light. Fungi appear white to blue. (Superior to KOH)

Verrucose Topography

wrinkled, convoluted surface

Umbonate Topography

button-like central elevation

Rugose Topography

furrows radiate out from the center

Texture with high aerial myelium

Cottony

Wooly

Glabrous Texture

smooth, no aerial mycelium

Granular Texture

dense and powdery

Arthroconidia

fragmentation of septate hyphae

Chlamydoconidia

Round, large conidia with a thick wall that are formed at the end, sides, or inside the hyphae.

Sporangium

Saclike structure containing spores in the asexual phase

Morphologic characteristics of Mucorales

Fluffy, white-gray to brown

"lid lifter"

Basiodobolomycosis

Woody, hard, painless nodule

Conidiobolus spp.

Primarily infect the tissue around the nose and on the face

Tinea corporis

ringworm of the body

Tinea cruris

ringworm of the groin

Tinea capitis

ringworm of the scalp

Tinea barbae

ringworm of the beard

Tinea unguium

ringworm of the nails

Tinea pedis

ringworm of the feet

Trichophyton Invasion: Endothrix

Hair shaft is filled with arthroconidia

Trichophyton Invasion: Ectothrix

Spores are found around the hair shaft

Differentiation of the organism T. rubrum and T. mentagrophytes

T. rubrum - does NOT perforate hair, slow growing

T. mentagrophytes - perforates hair, rapid growing

Fusarium

Microconidia are boat or sickle-cell shaped

Blastomyces spp.

Found in the Ohio and Mississippi River Valley regions.

Coccidioides spp.

Found in the deserts of southwest of the United States

Histoplasma capsulatum

Associated with inhalation of aerosolized conidia: chicken houses, roosting places for birds, bat guano (in caves)

Sporothrix spp.

Transmitted by traumatic inoculation or inhalation, aka "rose gardener" disease