Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

POD 3 > Mycology > Flashcards

Mycology Flashcards

1
Q

What is the difference between yeast and mold?

A

yeast-single cells, reproduce by budding

mold-long filaments (hyphae) or a mat (mycelium)

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

What are some general characteristics of fungi?

A

larger than bacteria
eukaryotic
membrane-ergosterol
cell wall-chitin, glucan, mannan

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

What are some characteristics of yeast?

A

unicellular
oval to round on microscopic examination
colonies resemble bacteria

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

What are some characteristics of mold?

A

multicellular
surface texture-cottony, wooly, velvety, granular
pigmentation
hyphae and spores

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

How are hyphae classified? What are the different types of hyphae?

A

presence of septa
reproductive hyphae
vegetative hyphae
aerial hyphae

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

What is a mycelium?

A

intertwined mass of hyphae

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

What is dimorphism?

A

capable of growing in mold or yeast

form under different environmental conditions (temperature, nutrients)

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

How do fungi reproduce?

A

binary fission
sexual
asexual
without nuclear fusion-arthrospore, blastospore, conidia

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

What are the pathogenic factors of fungi?

A

adhesins
antiphagocytic capsule
ability to survive in macrophage by H. capsulatum
lack of host resistance

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

What is the host response to a fungal infection?

A

high innate immunity

humoral response is limited and not protective

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

What increases susceptibility to fungal infections?

A

intrinsic-age, stress, nutritional status, pregnancy, diabetes
extrinsic-burns, steroid, immunosuppressive therapy, antibiotics

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

What is a KOH mount?

A

10% KOH added to specimen

digests tissue so fungi can be observed (can stain the fungi)

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

What is a calcifluor white stain?

A

Binds to polysaccharides in cellulose and chitin

fluoresces under UV light

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

What is the PAS stain?

A

Periodic acid forms aldehyde with chitin monomer in fungal cell wall
forms a red dye

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

What is the methenamine silver stain?

A

silver stains all fungi strongly but only few tissue components are stained

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

What is the pH of Sabouraud’s agar?

A

Acidic (5.6)

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

When is Wood’s lamp used?

A

diagnosis of dermatophytes

fluoresce under UV light

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

What are the different kinds of fungal infections?

A

superficial
cutaneous-tinea (ring worm)
subcutaneous-sporotrichosis
systemic-coccidioidomycosis, paracoccidiodomycosis, blastomycosis, histoplasmosis (lung is most common site)

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

What antifungals inhibit cell wall synthesis?

A

glucan-echinocandins (capsofungin)

chitin-nikkomycin

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

What inhibits cell wall synthesis through ergosterol?

A

azoles

allylamines

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

What causes direct membrane damage?

A

Polyenes

amphotericin-B

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

What inhibits nucleic acid synthesis?

A

flucytosine

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

What inhibits microtubules halting mitosis?

A

griseofulvin

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

What inhibits protein synthesis?

A

sordarins

azosordarins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What opportunistic fungal infections are yeast?
candida (dimorphic) malassezia furfur-lipophilic skin organism, mainly in neonates cryptococcus (fungi with capsule)
26
What opportunistic fungal infections are molds?
aspergillus | zygomycetes
27
What fungi looks like protazoa?
pneumocystis carnii
28
What are the morphological characteristics of candida?
yeasts, pseudohyphae (elongated single cells with constricted ends), and true hyphae with septations dimorphic
29
What are the risk factors for candida infection?
``` AIDS diabetes surgery, catheters, antibiotics neutropenia burns dialysis ```
30
What contributes to the pathogenicity of candida?
adhesins germ tube formation-hyphal formation associated with tissue invasion gliotoxin-immunosuppressive toxin
31
What are the clinical syndromes caused by candida?
thrush-white patches on oral mucosa (can be scraped off-unlike oral hairy leukoplakia) vaginal candidiasis-thick curd like discharge and burning dermatitis-diaper rash, intertringinous (associated with moisture) onychomycosis and paronychia-nails
32
How can candida be diagnosed?
stain from blood, tissue, sterile fluid, urine, CSF, skin, respiratory secretions Germ tube test-incubated in serum or plasma after 3-5 hrs at 37
33
How is candida treated?
mucosal or cutaneous-azoles (fluconazole, itraconazole, voriconazole, posaconazole) systemic-amphotericin B or flucytosine+ampho
34
What are morphological characteristics of aspergillus?
``` not dimorphic fungus septate hyphae conidial arrangement dichotomous branching acute branching angle ```
35
What clinical syndromes can be caused by aspergillus?
``` allergy sinusitis aspergilloma pulmonary aspergillosis disseminated aspergillosis ```
36
How is aspergillus treated?
amphotericin B
37
What are morphological characteristics of zygomycetes?
``` large hyphae grow rapidly coenocytic lack septa appear as hollow tubes resemble twisted ribbons ```
38
When is rhinocerebral mucormycosis likely to occur?
terminal event in patient with acidosis or uncontrolled diabetes invasive in severely burnt patients proliferate in nasal sinuses and invade into facial soft tissue, nerve, blood vessel, and brain
39
What are the symptoms of rhinocerebral mucormycosis?
``` facial pain headache persistent change in mental status blood-tinged nasal discharge bulging, discolored eye; fixed pupil ```
40
How is mucormycosis treated?
amphotericin B
41
What are characteristics of cryptococcus neoformans?
``` monomorphic yeast form acidic mucopolysaccharide capsule phenol oxidase positive-blocks epinephrine found in pigeon poop ```
42
What are the clinical syndromes from cryptococcus?
primary pulmonary infections-asymptomatic solitary pulmonary nodule on chest x-ray cryptococcal meningitis-hematogenous spread from lungs to meninges, symptoms of headache, mental status change, fever
43
How is cryptococcus diagnosed?
India ink-CSF capsular polysaccharide antigen serological test-based on detection of antigen not antibody
44
What are morphological characteristics of pneumocystis carini?
round cup shaped organism lacks ergosterol (ribotyping and DNA homology) obligate parasites-alveolar epithelium
45
What clinical syndrome is caused by pneumocystis?
interstitial pneumonia-resembles mycoplasma pneumonia | frequent in AIDS patients
46
How is pneumocystis diagnosed?
microscopy of BAL fluids | methenamine silver-stain reveals rounded cup shaped organism
47
How is pneumocystis treated?
sulfamethoxazole or pentamidine isothionate
48
Why have fungal infections increased?
advances in antibacterial therapies-resulting in fungal superinfections predisposing procedures-indwelling catheters predisposing treatments-chemo predisposing diseases-leukemia, AIDS
49
What is the MOA for amphotericin B?
binds to sterols (ergosterol) of the fungal plasma membrane alters membrane permeability results in leakage of essential cell contents fungistatic or fungicidal depending on concentration
50
Where does amphotericin B distribute?
poor CSF penetration-intrathecal administration
51
What are the adverse effects of amphotericin B?
nephrotoxicity-vasoconstrictive effect on afferent renal arterioles (decrease GFR), potassium/bicarb/magnesium wasting, decrease EPO production (reversible) hematologic-anemia
52
What are the infusion related effects of amphotericin B?
shaking, chills, fever, myalgias, arthralgias | premedicate with NSAIDs, acetaminophen, antihistamines
53
What is the spectrum of activity for amphotericin B?
``` aspergillosis paracoccidioidomycosis histoplasmosis cryptococcus blastomycosis candida-topical use coccidiodomycosis ```
54
What is the importance of the liposomal formulations of amphotericin B?
decrease in nephrotoxicity, no loss in efficacy higher dosing ABLC-invasive aspergillosis ABCD
55
What is the mechanism of action for flucytosine?
penetrates fungal cell wall deaminated to 5-fluorouracil by cytosine deaminase (specific to fungus) 5FU is an antimetabolite that competes with uracil and inhibits pyrimidine metabolism and RNA, DNA, protein synthesis
56
Where is flucytosine distributed?
CSF penetration
57
What are the adverse effects of flucytosine?
bone marrow hypoplasia (anemia, leukopenia, thrombocytopenia) elevated serum levels of hepatic enzymes
58
When should flucytosine be used and how?
serious candida and cryptococcus | never use alone due to resistance-synergistic with Amphotericin B
59
What is the mechanism of action for azole antifungals?
interfere with fungal cytochrome P450 dependent enzyme (14 alpha sterol demethylase) for conversion of lanosterol to ergosterol
60
What is the advantage of a triazole over a imidazole?
Triazoles have increased affinity for fungal CYPs rather than mammalian
61
What are the adverse effects of azoles?
nausea/vomiting | hepatitis
62
What can ketoconazole be used to treat?
Cushing syndrome dose dependent depression of testosterone and adrenocorticotropic hormone can result in gynecomastia, impotence, decreased libido
63
What are the drug interactions for azoles?
antacids, H2 agonists, PPI decrease absorption cycosporine and warfarin increased concentration less drug interactions for fluconazole, voriconazole
64
When is ketoconazole used?
``` histoplasmosis blastomycosis coccidioidomycosis candidiasis tinea/vaginal candidiasis-not FDA approved ```
65
What is the spectrum of coverage for fluconazole?
cryotococcal infections-meningitis coccidiodomycosis-excellent CSF penetration and less morbidity than intrathecal ampho B Candidiasis (resistance amoung krusei, glabrata)
66
Where does itraconazole distribute?
poor CSF penetration | not good for meningitis
67
What is the spectrum of coverage for fluconazole?
``` aspergillosis cryptococcal infections coccidioidomycosis histoplasmosis blastomycosis sporotrichosis dermatophytosis tinea unguium ```
68
What are the advantages of itraconazole use in therapy?
oral therapy for histo/blasto | when clinical improvement from ampho B can be transitioned to itraconazole
69
What is unique about the absorption of voriconazole?
decreased by high fat meals | high bioavailability
70
What are the drug interactions for voriconazole?
Rifampin, carbamezepine/phenobarbital decreases voriconazole AUC quinidine, sirolimus, ergot alkaloids increase drug concentrations
71
What are the adverse effects of voriconazole?
visual disturbances-blurred vision, color changes | rash, increased liver enzymes
72
When is voriconazole used?
invasive aspergillosis | candidiasis
73
When is posaconazole used?
similar to itraconazole can elevate LFTs used for candida and aspergillus inhibits CYP3A4
74
What is the mechanism of action of capsofungin acetate?
echinocandin-blocks fungal wall synthesis | glucan synthesis inhibitor (B 1,3 D glucan)
75
When is capsofungin used?
invasive aspergillosis | candida
76
What are the adverse effects of capsofungin acetate?
phlebitis, headache, fever | increased LFTs, SrCr-monitor
77
What is the mechanism of action for griseofulvin?
disrupts cell mitotic spindle structure | arrests cell division in metaphase
78
How is griseofulvin administerd? What does it treat?
orally | treats dermatophytosis
79
What are the side effects of griseofulvin?
``` nausea, vomiting, diarrhea hypersensitivity/rash hepatotoxicity nephrotoxicity P450 inducer-increase warfarin dose ```
80
What is the mechanism of action for terbinafine?
allylamine derivative | inhibits squalene epoxidase-step in sterol biosynthesis in fungi
81
What are the adverse reactions to terbinafine?
``` nausea/diarrhea hypersensitivity-erythema multiforme liver enzyme abnormalities hematologic effects-neutropenia, pancytopenia headache ```
82
How does the clearance of other drugs change with terbinafine?
increased clearance for rifampin and cyclosporine | decreased clearance for cimetidine and warfarin
83
When is terbinafine used?
onchomycosis-less drug interactions than itraconazole
84
How is nystatin administered?
oral suspension-swish and swallow | not absorbed from GI tract
85
What is the primary therapy for fungal infections?
creams, ointments, liquids
86
When are powders used?
mild lesions and tinea pedis prevnetion

POD 3 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions