Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

EV ACVD Study > Malassezia, Dermatophyte, Candida (NAVDF, Consensus x2) > Flashcards

Malassezia, Dermatophyte, Candida (NAVDF, Consensus x2) Flashcards

1
Q

Cell wall component of fungi

A

*Chitin (also arthropod exoskeleton)
*Chitosan
*Glucan
*Mannan

NO CELLULOSE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name of asexual reproduction spores

A

Conidia

Nonmotile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Fungi that are present on NORMAL dog and cat skin

A

*Alternaria
*Cladosporium

*Aspergillus
*Penicillium
*Rhizopus
*Trichoderma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Do cats with FIV/FeLV have MORE or LESS fungal diversity on their skin

A

MORE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Preferred temperature for fungi relative to body temperature

A

Fungi prefer LOWER temp than body temp

(physiologic barrier to fungal growth, along with oxidation-reduction potential)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Chemical barrier by keratinocytes against fungi

A

*Fungistatic fatty acids and sphingosines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

T or F: Clinically healthy pets cats can have Microsporum canis on skin

A

It is NOT a commensal

BUT it has been isolated on 2% of clinically healthy cats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Climate with more M canis

A

Tropical (17.5%) > temperate (4%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

At what temperature, seasona is Microsporum gypseum most common?

A

Humid, (sub)tropic

Summer, autumn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Are Dermatophytes sexual or asexual fungal organisms

A

Asexual (anamorphs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Zoophilic dermatophytes (adapted to animals)

A

M canis
M equinum
T equinum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Sylvatic dermatophytes (adapted to rodents/hedgehogs)

A

T mentagrophytes
M persicolor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Anthropophilic dermatophytes (adapted to humans)

A

Epidermophyton
T tonsurans
T rubrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Geophilic dermatophytes (adapted to soil, saprophytes)

A

M gypseum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Infective portion of dermatophyte? How does it form?

A

Arthrospore

Forms by segmentation and fragmentation of fungal hyphae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Predisposition (environment) for dermatophyte

A

*Young animals
*Overcrowded
*Dirty
*Damp
*Inadequate nutrition
*Immunosuppression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Predisposed breeds for M canis

A

*Yorkshire terrier
*Pekingese
*Persian
*Himalayan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Predisposed breeds for T mentagrophytes

A

Parson Russel Terrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

T or F: Daily baths with nonmedicated shampoo will help treat dermatophtysosis

A

FALSE

Excessive bathing/grooming can REMOVE fungistatic sebum and serum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

T or F: Fleas can transmit dermatophytes

A

True, potentially

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

T or F: If protected from UV light, dermatophyte- infected hair fragments can remain infectious for >18 months

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

3 main stages of dermatophyte infection

A

1) Arthrospores adhere strongly to keratin
-Mediated by adhesins on arthroconidia, proteases like subtilisins
-Within 2-6 hours of exposure

2) Conidial germination (germ tube emerges from arthroconidia, penetrates SC)

3) Invasion of cornified tissues by producing proteolytic enzymes (keratinase, elastase, collagenase)

Mechanical injury and humidity facilitate penetration

*Hyphae form arthroconidia within 7 days –> complete lifecycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where does dermatophyte infection STOP in the hair shaft

A

Adamson’s fringe/ keratogenous zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

In what phase of the hair cycle does dermatophyte growth cease?

A

Telogen, as no new keratin production

-Hairs are weak and easily broken

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Time of dermatophyte incubation (until lesions appear)

A

1-3 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Is humoral or cell mediated immunity more critical for dermatophyte clearance

A

Cell mediated (IFNg!, mac, neut)

(strong delayed-reactions on IDST in humans who can clear dermatophytosis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

T or F: cats who have received antifungal meds do not develop a robust cell-mediated immune response to dermatophytes, and are at risk of reinfection

A

True :(

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the dermatophyte antigen that is MOST immunologically active?

What type of hypersensitivity reaction does it produce?

A

Glycopeptide (cell wall)

-Carb portion: immediate-type hypersensitivity
-Peptide portion: delayed-type hypersensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Animal most likely to develop a fungal kerion

A

Dirty digging dogs

On face, forelimbs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Animal most likely to develop a Pseudomycetoma

A

Persian cat

Possible tissue grains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Clinical signs of Dermatophyte in cats that are easily confused as other diseases

A

*Uni or bilateral pinnal pruritus
*Recurrent chin folliculitis
*Recurrent stud tail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is #unique about Microsporum persicolor

A

Scaling, but no alopecia

Infects surface keratin, does NOT invade hair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Which dermatophyte species is least likely to cause alopecia

A

Microsporum persicolor

Infects surface keratin, does NOT invade hair

Scaling w/no alopecia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the name of the M canis metabolite that fluoresces with Woods Lamp

A

Pteridine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Woods lamp wavelength

A

320-400nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

T or F: If a hair is still fluorescing, you have not successfully treated the M canis infection

A

False. Hairs continue to fluoresce for a long time after negative culture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Are M canis spores endo- or ectothrix

A

Ectothrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

T or F: you may find dermatophyte macroconidia on a direct impression of an M canis lesion

A

FALSE. Macroconidia are never formed in tissue.

May seen ectothrix spores.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What type of hair will you see on Dermoscopy with dermatophytosis

A

Comma hairs

Slightly curved or broken hairs with homogenous thickness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What dermascopy findings would you expect with dermatophytosis vs alopecia areata

A

Dermatophyte: comma hair
Alopecia areata: Exclamation point hair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are the contents of Dermatophyte Test Medium (DTM)

A

*Nutrient medium
*Bacterial and saprophytic fungal inhibitors (gentamicin, tetracycline, cycloheximide)
*Phenol red - pH indicator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What temperature is ideal for DTM plates

A

Above room temperature has increased sporulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Is light or dark environments better for DTM plates

A

Doesn’t matter!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How long should you let a DTM sit before calling it negative overall

A

21 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

How often do you need to check your DTM plate

A

Daily. Need to determine if color changes prior to pathogen growth.

Dermatophytes will show color change WITH growth of pathogen. Use proteins (keratin) before carbs!

Nonpathogens will induce color change AFTER colony has grown. Use carbs before proteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Color of Microsporum mycelium on DTM

A

White-to-buff colored, powdery to cottony mycelium

Underside is yellow/orange

Flat with a depressed center

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

T mentagrophytes macroconidia, microconidia shapes

A

Macroconidia = Cigar (rare to see)
Microconidia = branched (common to see)
Hyphae are spiral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

M gypseum macroconidia shape

A

Ellipsoidal
Thin wall
<6 cells
Rounded distal end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

M gypseum colony on DTM

A

Cinnamon brown top
Powdery consistency
Yellow/tan underside
Flat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

M canis macroconidia shape

A

Spindle/canoe shape
Thick walls, outer spines
>6 cells
Terminal knob

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Trichophyton colony on DTM

A

White to cream top
Tan/brown/red bottom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Who is this

A

Saprophyte

Colonies that are grey, black, brown, green are NOT dermatophytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What should you do if there are no macroconidia on your cellophane tape sample from your DTM?

A

Repeat in 4-7 days. Some colonies produce spores as they mature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What color are dermatophytes on GMS stain

A

Black/brown on a pale green background

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What color are dermatophytes on PAS stain

A

Dark red on a lighter pink background

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

When is histopath most useful for diagnosis of dermatophytosis

A

Nodular forms

Otherwise, culture is more sensitive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

T or F: M canis will resolve in many cats without treatment

A

True. In about 3 months.

But rec tx in order to avoid shedding infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

T or F: Trichophyton and M persicolor will always resolve without treatment in healthy dogs

A

False. Chronic dermatophytosis can last up to 5 years in immunocompetent animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Definition of Mycological cure

A

2 negative cultures taken at least 2 week apart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Topical tx for dermatophytosis

A

2x/week
Lime sulfur, enilconazole, miconazole/chlorhexidine (NOT micon alone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Most effective, safe systemic treatments for Dermatophytosis

A

*Itraconazole (noncompound)
*Terbinafine

Do NOT use griseofulvin. It works but has AEs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

T or F: Lufenuron may work for dermatophyte

A

FALSE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Antifungal disinfectants to use in the environment

A

*Sodium hypochlorite
*Enilconazole
*Accelerated H2O2
*Potassium peroxymonosulfate

Use AFTER removing organic debris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Laundry protocol for dermatophyte household

A

AGITATION is what removes dermatophytes

Wash TWICE on LONGEST cycle

*Any temperature
*Does NOT need bleach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

How to clean wood floors in dermatophyte household

A

Swiffer sheet (electrostatic)
then wood oil soap

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

At risk human populations for Dermatophytosis

A

*Children
*Transplant/cancer patients
*Immunocompromised
*Elderly
*Vet professionals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Dermatophyte virulence factors

A

*Keratinolytic enzymes (keratinase)
*Endoproteases
*Exoproteases

Elastase, collagenase

Hydrolyze keratin
Allow invasion into hair shaft

68
Q

T or F: It is easy for normal skin be infected by a dermatophyte

A

False. Normal skin has too low humidity, antifungal substances on surface, normal resident flora

*Sebum = fungistatic fatty acids
*Continuous shedding of stratum corneum removes organisms as keratin is sloughed

69
Q

T or F: Malassezia pachydermatis can grown on a media without lipids

A

FALSE. Lacks fatty acid synthase gene (like all Malassezia)

Uses lipid fractions from within peptones of Sabouraud’s dextrose agar.

But technically called “non-lipid-dependent”, because it is the only Malssezia that can grow on Sabouraud’s dextrose agar

70
Q

Is Malassezia pachydermatis a pathogen or commensal

A

Commensal

Can become pathogenic if altered host microenvironment, immune system

71
Q

How to Malassezia pachydermatis reproduce

A

Budding

Broad base, monopolar

Thick cell wall

72
Q

Predisposed breeds to Malassezia in dogs

A

*Basset hounds
*WHWT
*Cocker Spaniels
*Toy/Mini poodles
*Dachshunds
*Boxers
*CKCS
*Shih tzu
*Australian, silky terriers
*GSD

*Bull terriers with Lethal Acrodermatitis

73
Q

Which genetic disease from MKLN1 can result in Malassezia infections

A

Lethal acrodermatitis in bull terriers

74
Q

If a dog has a Malassezia hypersensitivity based on IDST, we would expect their IgG and IgE to be ______

A

High titers

75
Q

Predisposing factors for Malassezia in cats

A

*Allergies
*Metabolic dz
*FIV/FeLV
*Paraneoplastic dz (pancreatic, thymoma)
*Breeds (Devon rex, Sphynx)

76
Q

Cat breeds with more Malassezia infections

A

Devon Rex, Sphynx

77
Q

What general temperature does Malassezia like

A

Increased heat and humidity

78
Q

What type of immune response is developed against Malassezia

A

Innate, antibody and cell mediated responses

Hypersensitivity reactions

79
Q

How do keratinocytes respond to Malassezia

A

*Identify Malassezia with TLRs
*Upregulate IL-10, TGFb (immunosuppressive)
*Downregulate IL-1a

80
Q

T or F: cell mediated responses to Malassezia can lead to a Type IV hypersenstivity in cAD patients

A

True

81
Q

What do claws infected with Malassezia look like

A

Pedal pruritus
Red/brown discoloration of claw
Ungual exudate

82
Q

Can Malassezia be reliably diagnosed on histopathology?

A

No. Surface scale + Malassezia is lost in tissue processing

Use cytology

BUT PAS, GMS is your best option.

83
Q

What culture media can you grow Malassezia pachydermatis on

A

Sabaroud’s dextrose agar

All other Malassezia require additional lipids!

84
Q

What culture media do you use for most Malassezia species

A

modified Dixons agar (lipid enriched)

1) contact plates = convenient
2) Detergent scrub sampling = gold standard but research only

85
Q

What do Malassezia colonies look like on culture

A

Cream to yellow
Smooth to lightly wrinkled
Glistening or dull
Margins are entire or lobate

86
Q

Where is Malassezia within the skin?

A

Stratum corneum

Topicals work great! Shampoos, gels, lotions

87
Q

Which topical therapies work for Malassezia dermatitis

A

Strong evidence for Miconazole 2% /Chlorhexidine 2% shampoo 2x/w

Moderate evidence for 3% chlorhexidine shampoo

88
Q

Best systemic antifungal therapies for Malassezia in dogs

A

Ketoconazole
Itraconazole

Terbinafine and fluconazole need additional studies.

Fun fact: paper in Vet Derm Jan 2024 shows Fluconazole is noninferior to Itra for Malassezia!

89
Q

Best systemic antifungal therapies for Malassezia in cats

A

Itraconazole

90
Q

How well does ASIT work for Malassezia hypersensitivity

A

Improvement noted in studies

Needs more data

91
Q

T or F: Malassezia is zoonotic

A

RARE. Very low risk. But hand hygiene for immunocompromised people

92
Q

PAMPs identify _____ on Malassezia

A

*Mannan
*Zymosan

93
Q

PRRs for Malassezia

A

C-type lectins! Need Ca2+ to bind carbohydrates

*Langerin
-Recognizes mannose, beta-glucans
-on Langerhan cells
Many fungi recognized

*Mincle
-Recognizes glucosyl and mannosyl-glycolipids
-on Phagocytes
Malassezia specific

*Mincle + Dectin 2 stimulate proinflam cytokines (TNFa, MIP2, TNFa)

94
Q

Malassezia virulence factors

A

*Hydrolases (lipase, phospholipase, aspartyl protease, acid sphingomyelinase)

*Biofilm

95
Q

Antimicrobial resistance in Malassezia (2)

A

1) Increased expression of ERG11 gene

Encodes lanosterol 14-alpha-demethylase (Azole target)

2) Increased expression of Drug efflux pumps (CDR1, CDR2; MDR1)

96
Q

T or F: Candida are commensals of MC junctions, GI tract, Genital tract

A

True

RARE to cause infections in animals

97
Q

Most common species of Candida isolated from animals

A

Candida albicans

98
Q

Immune response against Candida

A

Neutrophils
T cell mediated immunity

99
Q

Culture media, colony color, organism shape for Candida

A

Blood Agar
Sabouraud’s Dextrose agar

Cream-white colonies

Rounded yeasts, pseudohyphae, septate hyphae

100
Q

Where do Candida yeast versus hyphase live in the skin

A

Yeast are on the surface

Hyphae, pseudohyphae extend into epidermis

101
Q

Are Candida zoonotic

A

No

102
Q

Virulence factors for Candida

A

*Ligands for adherence
-Afflutinin-like (AL) family
-Hyphal wall protein (Hwp) family

*Adhesins: Mannose, mannoproteins

Bind to receptors on epithelial cells: E cadherin, fibrinogen, fibronectin, thrombin, collagen, laminin, vitronectin-binding proteins

*Invasin proteins (affect mucosal skin)

*Aspartyl proteinases are hydrolytic, injure mucosa

103
Q

Most common Malassezia sp in cat ears

A

Malassezia nana

104
Q

Most common Malassezia species in cat clawfolds

A

Malassezia sloofiae

105
Q

Most common Malassezia species on the cat overall

A

Malassezia pachydermatis

106
Q

What stimulates phospholipase activity in Malassezia pachydermatis?

A

Endogenous opiod peptides

Beta-endorphins in skin of dogs with dermatitis

Higher phospholipase activity in OE/dermatitis dogs

107
Q

What cell surface markers are expressed by Langerhans cells when activated by Malassezia

A

CD83 initially

Then increase in CD80, CD86

108
Q

Malassezia antigens are resistant to lysis by WHICH cell type

A

NK cells

109
Q

What immune response type is present against Malassezia

A

Th2

Increased IL-4, IL-5, IL-10, IL-13

110
Q

Which immunoglobulins are elevated in Basset hounds with Malassezia dermatitis

A

IgG, IgA

IgG4 induces Th2 response; correlated with IgE concentration in cAD

111
Q

T or F: IgE against Malassezia is higher in atopic dogs than healthy dogs

A

True

But IgE not higher in OE ears than healthy. Infection is not dependent on hypersensitivity

112
Q

What type of immune responses can occur against Malassezia

A

Type 1 (IgE sensitized mast cells)

Type 4 (contact hypersensitivity, Delayed type T cell hypersensitivity)

113
Q

T or F: IgG against Malassezia may offer some protective immunity

OR

IgG may activate the complement system, to cause epidermal damage/inflammation

A

True

114
Q

T or F: The Consensus Guidelines recommend IgG testing for Malassezia dermatitis

A

False. Do NOT recommend

115
Q

T or F: More Malassezia pachydermatitis correlates with higher CADESI-3

A

True

116
Q

High levels of phospholipase A2 is associated with _____ (increased vs decreased) pathogenicity of Malassezia pachydermatis

A

Increased!

Subtype 3D has higher PLA2, more pathogenic in dogs

117
Q

Pulse antifungal therapy for Malassezia

A

Itraconazole 5 mg/kg 2d/week consecutively

May work bc accumulation of lipophilic itraconazole in SC

118
Q

MOA terbinafine

A

Synthetic allylamine derivative

Inhibits fungal ergosterol biosynthesis at SQUALENE EPOXIDATION step

119
Q

MOA Nystatin

A

Polyene cyclic macrolide

Altered cell membrane permeability; preferential binding to ergosterol

120
Q

T or F: aminoglycosides may work against Malassezia pachydermatis

A

TRUE! need more studies though

121
Q

Combination of multiple antifungal drugs may have ________ effects (ie caspofungin and flu/itraconazole)

A

Synergistic

122
Q

2 causes for high MIC needed against Malassezia pachydermatis

A

ERG11 mutation

Biofilm

BUT topical products do get high MICs!

123
Q

T or F: we have excellent CSLI and EUCAST breakpoints for M pachydermatis

A

FALSE. But regardless, M pachydermatis seems susceptible to most azoles.

124
Q

What ear treatment may be effective at preventing Malassezia otitis externa

A

Hydrocortisone aceponate 2x/w

125
Q

T or F: Cats with FIV/FeLV are at increased risk for dermatophytosis

A

FALSE. They are NOT at increased risk

126
Q

Major dermatophyte of hedgehogs

A

Trichophyton erinacei

127
Q

Major dermatophyte of guinea pigs

A

Arthroderma benhamiae

128
Q

Major dermatophyte of cats, dogs, rabbits, rodents (mice, chinchillas)

A

Arthroderma vanbreuseghemii

129
Q

Major dermatophyte of horses

A

Trichophyton equinum

(also Microsporum equinum, but more rare)

130
Q

Major dermatophyte of monkeys, poultry, dogs

A

Trichophyton simii

(India only)

131
Q

Major dermatophyte of chickens

A

Trichophyton gallinae

132
Q

Major dermatophyte of rodents, voles

A

Microsporum persicolor

133
Q

Major dermatophyte of pigs

A

Microsporum nanum

134
Q

Major dermatophyte of horses, donkeys

A

Trichophyton bullosum

135
Q

Major dermatophyte of mice (favus)

A

Trichophyton quinckeanum

136
Q

Major dermatophyte of the soil (geophilic)

A

Microsporum gypseum

137
Q

T or F: many dermatophyte infections come from contact with a contaminated environmental

A

FALSE. Uncommon. Usually need contact with cat, rodent

(except geophilic)

138
Q

Endoproteases secreted by dermatophytes

A

*Substilisins
*Fungalysins

Digest keratin into usable peptides and amino acids

139
Q

Function of SSU1 gene (dermatophyte)

A

Encodes for Dermatophyte Sulphite Efflux Pump

-Degrades disulfide bonds between keratin cysteines

140
Q

cdo1 function (dermatophyte)

A

*Cysteine dioxygenase

Regulates sulfite formation from cysteines in keratins

Helps with keratin degradation

141
Q

2 genes important for keratin degradation (dermatophytes)

A

SSU1: dermatophyte sulphite efflux pump

Cdo1: cysteine dioxygenase

142
Q

T or F: Microsporum gypseum and Microsporum persicolor will fluoresce on Woods Lamp

A

FALSE

143
Q

If a dermatophyte grows on DTM, what color change occurs

A

Before: Yellow
W/Dermatophyte: Red

Change in pH. Dermatophytes release alkaline metabolites

144
Q

Is Lime Sulfur fungicidal or fungistatic?

Keratolytic or keratoplastic?

A

Fungicidal
Formation of Hydrogen sulphide

Keratolytic

145
Q

AE of Lime Sulfur

A

Oral ulcerations (don’t let cats lick!)

146
Q

MOA of chlorhexidine

A

Biguanide compound

Affects cell membranes at low concentrations

Congeals cytoplasm at high concentrations

147
Q

MOA of essential oils against dermatophytes

A

Fungal cell wall damage

-Slows growth
-Destroys intracellular organelles

148
Q

Is Itraconazole fungistatic or fungicidal

A

Low doses: Fungistatic
High doses: Fungicidal

149
Q

MOA of itraconazole

A

Inhibits fungal cytochrome P450 enzyme (140alpha demethylase)

Prevents conversion of lanosterol to ergosterol

Ergosterol needed for cell wall integrity, activity

150
Q

Can you use itraconazole in pregnant animals?

A

No. Embryotoxic, tertogenic at high doses

151
Q

Which antifungal medication is associated with vasculitis at doses >10mg/kg

A

Itraconazole

152
Q

Which medications can you NOT combine with itraconazole, ketoconazole (lipophilic, concentrate in sebaceous glands).

A

Gastroprotectants/ antacids. Will decrease bioavailability

Need low GI pH to be absorbed.

153
Q

T or F: Ketoconazole’s interference with endogenous steroid synthesis is irreversible

A

False. Steroid synthesis issues do occur with ketoconazole, but it is reversible

154
Q

What happens if you combine ketoconazole with ivermectin, midazolam in dogs

or

Cyclosporine in dogs, cats

A

INCREASED plasma concentrations

(azoles = fungal Cytochrome p450 inhibitors)

155
Q

What is different about fluconazole compared to the other azoles

A

*Water soluble, minimally protein bound
-Others are lipophilic
*NOT affected by concurrent antacids, do not need food for absorption
*Poor efficacy against dermatophytes

156
Q

T or F: Terbinafine affects the Cytochrome P450. Caution with other medications

A

FALSE. Terbinafine does NOT affect Cyp450 (keto and itra do!)

157
Q

Which antifungal medication has the LOWEST MIC for Microsporum and Trichophyton

A

Terbinafine!

Compared to itraconazole, fluconazole, ketoconazole and griseofulvin: terbinafine has the lowest MIC for Microsporum sp. and Trichophyton spp

158
Q

Does terbinafine persist in SC or sebum at higher concentration than serum (like itrafungol)

A

No

However, terbinafine is highly concentrated in cat hair

159
Q

MOA of griseofulvin

A

Binds fungal tubulin –> causes mitotic arrest in METAPHASE

Inhibits nucleic acid synthesis, cell mitosis

Fungistatic

160
Q

AEs of griseofulvin

A

Lethargy, pyrexia, anorexia, depression, ataxia, upper respiratory signs, leukopenia, pancytopenia

Potent inducer of P450 enzymes

Need CBC q2w.

161
Q

MOA of Amphotericin: “polyene class”

A

Irreversibly binds/alters fungal membrane sterols (ergoserol) –> creates pores in cell membrane

NEPHROTOXIC

Activates macrophages
(Nystatin is also a polyene)

162
Q

Which antifungal causes toxic epidermal necrolysis in dogs

A

Flucytosine

163
Q

Which antifungals are a POOR choice for aspergillosis

A

Fluconazole (intrinsic resistance), ketoconazole (ineffective)

164
Q

MOA capsofungin

A

Inhibits 1,3-beta-glucan synthase

(important for beta glucan synthesis of fungal and oomycete cell wall)

165
Q

What disease does Candida cause in veterinary medicine ains living fungi ONLY

A

Thrush (white tongue) on pigs

166
Q

Which 2 dermatophytes are in the stratum corneum ONLY (not in hair follicles)

A

1) Trichophyton mentagraphytes
2) Microsporum persicolor

EV ACVD Study (52 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions