Dermatophytes Flashcards
Dermatophytes are _______ that infect only ___________ epidermal structures including?
molds, keratinized, superficial skin, hair, feathers, horns, hooves, claws, and nails.
Infections caused by dermatophytes are called?
ringworm or dermatophytosis.
Other yeast and saprophytic fungi cause __________ infections _______ infections caused by dermatophytes; hence the generic term _________ is used to represent all fungal infections of skin.
cutaneous, mimicking, dermatomycosis
Dermatophytes: Morphology
* No __________ state (culture): produce _______, ________ hyphae collectively
called _________.
* The asexual reproductive units (______) are found in the _____ mycelium.
* They can develop ________ and _________.
parasitic, septate, branching, mycelium, conidia, aerial, microconidia, macroconidia
List the Hyphal characteristics.
spirals, nodules, rackets, chandeliers, and
chlamydioconidia (chlamydiospore)
Dermatophytes Parasite state: only ______ and __________ (_______) another asexual
reproductive unit are seen. Sexual spores (_______) are ____ in the parasitic phase.
hyphae, arthroconidias, arthrospores, ascospores, absent
What can be seen in the image below?
What are the Three important genera of Dermatophytes?
Microsporum, Trichopyton in animals, and Epidermophyton primarily in humans
What is the traditional culture medium for identifying Dermatophytes?
Saboroud’s dextrose agar
Some dermatophytes in ____ and ____ (but not in ______) produce _______ __________ visible under ultraviolet light (366nm, Wood’s light) (?)
skin, hair, culture, green fluorescence, Microsporum canis
What can be seen in the image below?
Some dermatophytes in skin and hair (but not in culture) produce
green fluorescence visible under ultraviolet light (366nm, Wood’s
light) (Microsporum canis)
What can be seen in the image below?
Some dermatophytes in skin and hair (but not in culture) produce
green fluorescence visible under ultraviolet light (366nm, Wood’s
light) (Microsporum canis)
What can be seen in the image below?
Some dermatophytes in skin and hair (but not in culture) produce
green fluorescence visible under ultraviolet light (366nm, Wood’s
light) (Microsporum canis)
How are Dermatophytes transmitted?
- Transmission: Direct and indirect
Dermatophytes Pathogenesis:
Proteolytic enzymes (elastase, collagenase, keratinase). Inflammation
with high iron influx, iron is available for fungi growth.
Infectious unit (________) –> defect in ________ ______ –> ?
development –> hyphae develops into _________ –> growth pattern in ________ skin –> hair invasion (________) –> germination with ____ formation –> ______ strands growth ____ the hair.
Conidium, stratum corneum , germ tube, hyphae branch, arthroconidia, hairless, ringworm, spore, hyphal, along
Accumulation of arthroconidia outside the hair shaft = ?
Accumulation of arthroconidia inside the hair shaft = ?
ectothrix, endothrix
Ringworm normally regress __________, unless ________ bacterial infection(s) is present.
spontaneously, secondary
________ animals are more susceptible to dermatophyte infection. Crowding of animals increased ________. Dermatophytes are ________ distributed.
Young, prevalence, globally
___________ IR has limited role in protection, ________ IR is decisive in protection and recovery. _______-mediated and _______-mediated hypersensitivity may occur. ____________ __.________ vaccine is used in Europe in cattle.
Humoral, cellular, Antibody, cellular, Mycelial T. verrucosum
Dermatophytes: Laboratory diagnosis
- M. ______ and M. _______ may emit fluorescence (Wood’s lamp)
canis, audouini
What samples would you collect if trying to diagnose a patient with Dermatophytes? What would you do with those samples?
- Skin scrapings and hair samples for hyphae and arthroconidia observation + 10-20% KOH
What stain would you use to ID dermatophytes?
Stain: lactophenol cotton blue
What culture would you use to ID dermatophyte infection? At what temperature and for what period of time?
- Culture: Sabouraud’s dextrose agar, 25°C, up to 4 weeks
if conducting PCR, what gene would you look for?
- PCR: chitin synthase 1 gene
How would you treat a dermatophyte infection? Control?
- Treatment: topical and systemic; miconazole, econozole,
ketoconazole, itraconazole, and thiobendazole.
Betadine, chlorhexidine (lotions, ointments) - Control: disinfection of utensils, equipment and facilities. Screening animals with Wood’s lamp
Microsporum canis is generally regarded as a _________ dermatophyte, but it often attacks humans. Most human infections
are acquired from ______. It is the etiologic agent of roughly ____% of the cases of feline ringworm and about ____% of the
cases of canine ringworm in North America; in cats, the infection is most often _________, whereas in dogs, the disease is
more ______. The _____ is the most common site of infection, with areas of ______ around the nose, eyes, and ears, but
the infection can become _______. In addition to humans, cats, and dogs, numerous animals can serve as hosts (?) Microsporum canis produces a _____-_________ fluorescence in _____, and it is associated with small _______ spores. Its colonies are _____ to ____ in color with a characteristic ____, to ______-____ reverse
zoophilic, animals, 98, 70, subclinical, obvious, head, alopecia, generalized, bats,
canaries, cattle, chimpanzees, chinchilla, donkeys, foxes, gibbons, goats, gorillas, guinea pigs, horses, jaguars, lions, lynx,
monkeys, orangutans, pigs, rabbits, sheep, tigers, and others., yellow, greenish, hair, ectothrix, white, buff, yellow, orange-brown
What condition is this person suffering from? Explain the causative agent. What can be seen in the slides on the left and in the middle?
Ringworm infection cuased by Microsporum canis.
Microsporum canis produces a yellow-greenish fluorescence in hair, and it is associated with small ectothrix spores. Its colonies are white to buff in color with a characteristic yellow to
orange-brown reverse.
Microsporum gypseum. This is a __________ dermatophyte that often attacks ____ and ______. It has been isolated from these species (?). _________ _______ spores are typical but ____ in number, and
fluorescence is _____ or ____. The colonies grow ____, producing a _____, ______, ____ to _______
brown surface with a pale ______ to ___ reverse.
geophilic, humans, animals, baboons, buffaloes, cats, cattle, chickens, chimpanzees, chinchillas, dogs, fowl,
guinea pigs, horses, leopards, monkeys, mice, parrots, rabbits, rats, squirrels, tapirs, tigers, and other species (7)
large, ectothrix, few, dull, absent, fast, flat, powdery, buff, cinnamon, yellow, tan
What condition is this animal suffering from? Explain the causative agent. What can be seen in the slides on the right and in the middle?
Ringworm caused by Microsporum gypseum.
The colonies grow fast, producing a flat, powdery, buff to cinnamon
brown surface with a pale yellow to tan reverse.
What microbe can be seen here?
What microbe can be seen here?
What microbe can be seen here?
What microbe can be seen here?
Trichophyton erinacei is a _______ dermatophyte primarily associated
with ringworm in _______, but occasionally it has been isolated from ____ and ____, ____, and ______. Hair invasion is normally ______. The perfect state has ___ been reported. Colonies can be described as?
zoophilic, hedgehogs, mice, rats, dogs, humans, ectothrix, not, flat, powdery, white to ivory white, with a clear yellow diffusing pigment
underneath
What condition this patient suffering from? What microbe causes this condition?
Ringworm caused by Trichophyton erinacei.
What microbe causes this ?
Trichophyton erinacei.
Colonies are flat,
powdery, white to ivory white, with a clear yellow diffusing pigment
underneath
What can be seen in the image below?
Trichophyton equinum is a ________ species that
rarely attacks ______; it causes ringworm in _____ and ______, and occasionally, in ____. _____ and _____ are most susceptible, at first
developing swellings that can be felt through the ____. These can progress to small
________ ______ with an ____, a condition often
known as ______ ____. ______ develops as the
lesions enlarge and turn chronic; _____ may fall off
from healed lesions, leaving _____ areas with a ____ eaten appearance.
Hair invasion is by large ______ spores; there is
no _________, and the perfect state has ____
been reported. Colonies are described as?
zoophilic, humans, horses, donkeys, dogs, Foals, yearlings, hair, inflamed ulcers, exudate, girth itch, Alopecia, crusts, bald, moth, ectothrix, fluorescence, not
white to cream- colored with a bright yellow to dark pink or brown reverse
What condition is this animal suffering from? What is the causative agent?
Ringworm, Trichophyton equinum
What microbe causes this ?
Trichophyton equinum
Presently, T. verrucosum
is regarded as the primary cause of ringworm in _____.This _____ dermatophyte often attacks _____; it has been isolated
from (?).
Trichophyton verrucosum produces very _______ ______ spores in ____. Infected hair in humans is not _______, but some florescence
has been noted in ___. Colonies are ____ growing, _______, deeply ______, and _____ to _____. Unlike other dermatophytes, the organisms grows best at ____°C .
cattle, zoophilic, humans, buffalo, canaries, cats, cattle, dogs, donkeys, dromedaries,
fowl, goats, horses, mules, pigs, sheep, and zebu.
large ectothrix, chains, fluorescent, cattle, slow, heaped, folded, white, yellow, 37
What condition is this animal suffering from? What is the causative agent?
Ringworm, T. verrucosum
What microbe causes this ?
T. verrucosum
Colonies are slow growing, heaped, deeply folded, and white to yellow.
What microbe can be seen here?
T. verrucosum
Epidermophyton floccosum is the only ______ accepted species in this genus. E. floccosum infects only ____ and _____, and it is virtually confined to _____. Reports of infections in domestic animals are essentially ______, but there are some of isolations from ____ and from a ____. Since ____ is not attacked, there is no ______ under Wood’s lamp. Colonies are usually ?
widely, skin, nails, humans, nonexistent, mice, dog, hair, fluorescence, greenish yellow, olive, or khaki, powdery, with radial furrows and a yellow to tan reverse
What condition is this animal suffering from? What is the causative agent?
Tinea pedis
Epidermophyton floccosum
What can be seen here?
Macroconidia
What can be seen here?
Epidermophyton floccosum
Colonies are usually greenish yellow, olive, or khaki, powdery, with radial furrows and a yellow to tan reverse.
What can be seen here?
Chlamydioconidia
