Agents of Superficial Mycoses Flashcards
What specific part of the epidermis do superficial mycoses affect?
stratum corneum
True or False.
Superficial mycoses induce an inflammatory reaction in the host.
False.
(Patients who suffer from superficial fungal infections do not show any overt symptoms because the fungal agents do not activate any tissue response or inflammatory reaction)
Identify the causative agent.
Tinea versicolor
Pityriasis versicolor
Malassezia furfur
Identify the causative agent.
Black piedra
Piedraia hortae
Identify the causative agent.
White piedra
Trichosporon spp.
Identify the causative agent.
Tinea Nigra
Hortaea werneckii
Identify the causative agent.
dandruff
Malassezia furfur
Identify the disease.
- pale patchy, scaling lesions
- “dandruff”
- more evident during warm months
Tinea versicolor / Pityriasis versicolor
Identify the disease.
- on hairs of the scalp
- hard, dark brown to black gritty nodules that are firmly attached to the hair shaft.
Black piedra
Identify the disease.
- on the hair shaft, face, and pubic region
- soft mycelial mat
- infect immunocompromised patients’ blood, CSF, and organs
- Endemic in tropical areas (South America, Africa, and parts of Asia)
White piedra
Identify the disease.
- brown to black nonscaly macules
- on palms of hands and soles of feet
Tinea nigra
What is the growth requirement for M. furfur?
lipids
Specimen of choice for M. furfur
skin scrapings
Identify the agent.
▪ 4-8 um budding yeats
▪ septate, branched hyphae
▪ “Spaghetti and Meatballs” fungus
Malassezia furfur
Culture media for M. furfur
Fungal Culture Media + Olive Oil
Describe the colonies of M. furfur
cream-colored, moist, and smooth
What is the method of identification used for M. furfur that observes yellow fluorescence?
Wood’s lamp
What is inside the hard, dark brown to black gritty nodules of a black piedra disease?
asci with 8 ascospores
Laboratory diagnosis preparation for Malassezia furfur.
KOH preparation
Identify the agent.
Thick-walled rhomboid cells containing ascospores
Piedraia hortae
Culture media for Piedraia hortae
Sabouraud dextrose agar (SDA)
Describe the colonies of Piedraia hortae.
brown, restricted colonies
What has been described as an extremely variable human pathogen?
Trichosporon beigelii
How many species are included in the Trichosporon spp.?
19
What is the most important species of Trichosporon spp.?
Trichosporon asahaii
What Trichosporon spp. causes systemic disease and is recovered frequently from the cerebrospinal fluid (CSF) as a cause of meningitis.
Trichosporon mucoides
What species resembles the colonies of Trichosporon spp.?
Cryptococcus neoformans
Enumerate the microscopic elements that can be seen on Trichosporon spp.
arthroconidia
hyphae
blastoconidia
Identify the agent.
- Carbohydrate (-) Non-Fermenter
- Potassium Nitrate (+) Utilizer
- Urease (+)
Trichosporon spp.
Laboratory diagnosis preparation for Hortaea werneckii.
10% to 20% KOH
Identify the agent.
▪ septate hyphal elements
▪ Younger: budding cells (blastoconidia)
▪ Older: hyphae with blastoconidia in clusters
▪ Annelloconidia are seen in older hyphal colonies
Hortaea werneckii
Describe the colonies of Hortaea werneckii.
shiny, moist, yeastlike colonies
