Mycology Flashcards
1
Q
Dematiaceous organism that causes dermatophytosis?
A
Epidermophyton floccosum
2
Q
Fungal organism that causes athletes foot?
A
Trichophyton mentagrophytes
3
Q
Hair perforation test
A
Prepubital hair is cut into 1cm pieces and placed in 25 mL of sterile water.
Incubated for ~4 weeks and interpreted with lactophenol cotton blue
4
Q
Endothrix hair infections
A
Fungal organism has the ability to penetrate the hair shaft
5
Q
Exothrix hair infection
A
Fungal organism only seen on the surface of hair shaft
6
Q
Fungal organism positive for endothrix infection
A
Trichophyton mentagrophytes
7
Q
Fungal organism negative for endothrix infection
A
Trichophyton rubrum
8
Q
Urease test
A
Performed the same way it is performed for bacteria cultures
9
Q
Fungal species that is negative for urease
A
Trichophyton rubrum
10
Q
Common characteristics of fungal organisms
A
All are considered heterotrophs, obtain nutrients by absorption through surrounding environments.
Cell walls are made up of carb chitin, all are eukaryotic.
11
Q
Rice grain agar
A
Rice purchased @ grocery store, used to differentiate between Microsporum canis & Microsporum audoinii
12
Q
Microsporum audouinii on rice grain agar
A
Grows poorly or not at all. Where the organism was inoculated will turn brown.
13
Q
Microsporum canis on rice grain agar
A
Will show good growth and media will turn yellow from the pigment produced by the organism.
14
Q
Hyaline
A
Nonpigmented.
Appear blue because of the lactophenol cotton blue stain
15
Q
Dematiaceous
A
Dark pigmentation.
Colonies have melanin and appear dark green/black
16
Q
Hortaea werneckii
A
Cause of tinea nigra
17
Q
Malassezia furfur
A
Cause of pityriasis versicolor-folliculitis, catheter-associated sepsis, dandruff
18
Q
Piedraia hortae
A
Cause of black peidra
19
Q
Trichosporon spp.
A
Cause of white peidra (disseminated disease of immunocompromised patients with neutropenia)
20
Q
Cottony morphology
A
High aerial hyphae or loose and course texture
21
Q
Velvety morphology
A
Low aerial hyphae
22
Q
Granular/powdery morphology
A
Flat, crumbly
23
Q
Glaborous
A
Smooth or waxy morphology
24
Q
Flat
A
Having no topography
25
Rugose
Hilly, veins radiate out from center
26
Umbonate
Circular depression or elevation in the center
27
Verrucose
Wrinkled, veins go in any direction throughout the colony
28
Structures in cell wall of fungal organisms
Mannoproteins, B-glucan (1,3 & 1,6), chitin, Phospholipid bilayer of cell membrane
29
Phialophora verrucosa
Conidiogenous cells, phaeoid, flask-shaped phialides with collarettes
Conidia is one-celled & occur in balls at tips of phialides
30
Fonsecaea pedrosoi
Primary one-cell conidia formedon sympodial conidiophores.
| Primary conidia function as conidiogenous cells to form secondary one-celled conidia.
31
Fonsecaea compactum
Similar to F. pedrosoi but with more compact conidial heads
32
Cladophialophora carrionii
Erect conidiophores bearing branched chains of one-celled, brown blastoconidia. Conidium close to tip of conidiophore, termed shield cell
33
Chromoblastomycosis
Sclerotic bodies are seen in the tissue & leading cause is Fonsecaea pedrosoi
34
Phaeohyphomycosis
Mycelium are seen in the tissue & leading cause is cladophialophoria bantianai
35
Mycetoma
Granules are seen in the tissue & leading cause of white grain mycetoma is Acremonium
36
Sporotrichosis
Not noted with a characteristic structure in the tissue. Leading cause is Sporothrix schenckii
37
Other terms used to describe chromoblastomycosis
Verrucous dermatitis, sclerotic bodies, cauliflower lesions
38
Intraconazole
Administered orally or by IV - belongs to the Triazole group
| Mode of action 14-a demethylase
39
Lactophenol cotton blue
Used as mounting fluid & stain.
Lactic acid acts as a clearing agent and a preservative for the organism
Phenol is a killing agent.
Cotton blue (aniline blue)
40
Gram stain
Most fungal organisms appear dark blue
41
Acid-fast stain
Used to differentiate eumycotic organisms
42
India Ink
Used for the identification of the capsule produced by Cryptococcus neoformans
43
Calcoluor white
Fluorescent stain that is absorbed by the chitin found in the cell wall of the fungal organism
44
Acitnomycotic mycetomas
Caused by bacterial organisms
45
Eumycotic mycetomas
Caused by fungal organisms
46
Organisms associated with actinomycotic mycetomas
Actinomadura, Nocardia, Streptomyces
47
Organisms associated with eumycotic infections
Pseudallesheria boydii, Rhinocladiella, Madurell, Exophiala jenselmei, Acremonium, Fusarium, Vurvaularia
48
Aspergillosis
Very rare fungal disease that is caused by Aspergilis species
49
Those @ risk for aspergilosis
Patients with hematological malignancies
50
Allergic bronchopulmonary aspergillosis (ABPA)
Seen in patients with asthma or cystic fibrosis
| Charcot-Leyden crystals may be present
51
Invasive aspergillosis
Damages body tissue in patients who are immunocompromised
| "fungus balls" are often seen
52
Effective treatment against aspergillosis
Voriconazole
53
Aspergillus flavus
Second most common cause of invasive aspergillosis. Can also cause sinusitis & nail infection.
54
Aspergillus flavus morphology
Bright yellow-green colony.
| either uniserate or biseriate phialides that cover most of the vesicle. Canidiophores are long and rough
55
Aspergillus fumigatus
Most common cause of invasive aspergillosis, allergic aspergillosis, sinusitis. Can cause lung infection in immunocompromised patients.
56
Aspergillus fumigatus microscopic morphology
Produces uniseriate phialides on the upper portion of the vesicle, conidia are round, and seen in chains, conidiophores are short/smooth
57
Aspergillus nidulans
Cause infections of various organs in immunocompromised patients
58
Aspergillus nidulans microscopic morphology
Biserate phialides are seen on the upper half of the vesicles. Conidiophores are short, smooth, and brown. Hulle cells and cleistothecium can be seen
59
Aspergillus niger
Common cause of aspergilloma, can cause external ear canal infections & chronic otitis media. It can disseminate in immunocompromised patients
60
Aspergillus niger morphology
Macro: appear white, but turn black with age
Micro: produces biseriate phialides around a large vesicle. Conidia are produced in chains and are brown. Conidiophores are long & smooth
61
Aspergillus terreus
Causes infections throughout the body, can disseminate, intrinsically resistant to amphotericin B.
62
Aspergillus terreus morphology
Microscopically produces biseriate phialides on the upper half of the vesicle, the conidia appear round & in chains. Conidiophores are short & smooth
63
Aspergillus versicolor
common cause of nail infections. Rarely cause pulmonary infections
64
Aspergillus versicolor morphology
Red exudate.
Biserate phialides that cover 1/2 to entire vesicle: conidia are round & in chains. Hulle cells maybe present. Conidiophores are long & smooth
65
Zygomycetes macroscopic morphology
Aseptate
| Fluffy white, gray or brown colonies that cover entire agar surface in 1-2 days
66
Zygomycetes microscopic morphology
Broad, septate, ribbon-like hyphae with sporangia. Sporangia contain small sporangiospores.
Most produced rhizoids
67
Patient population affected by Zygomycetes
Diabetics in ketoacidosis (organism likes acidic environments)
68
Cuninghamella morphology
single sporangioles, rare rhizoids
69
Lichthemia corymbifera complex morphology
Ability to grow at 52 degrees C. Wide hyphae & rhizoids are seen between sporangiophores. Sporangia are small & pear shaped
70
Mucor morphology
Wide hyphae, sparsely spetate, no rhizoids, long sporangiophores, sporangia filled with round spores
71
Rhizopus morphology
Wide hyphae, rhizoids directly under sporangiophores. Sporangia are large, round, dark
72
Syncephalastrum morphology
Broad hyphae, short branched sproangiophores, tubular sporangia, rhizoid presnet
73
Tease mount method
One drop of lactophenol cotton blue on a slide, remove small portion of the colony with a sterile loop & dissecting needle, carefully tease portion of colony into the drop of LPCB and coverslip. Read microscopically. NOT BEST METHOD FOR PRESERVATION
74
Cellophane tape method
Use about 1.5 inch piece of clear cellophane tape, bend so sticky part of tape is out, firmly touch surface of fungal culture & gently pull away. Aerial hyphae will adhere to the tape, place on top of drop of LPCB & read microscopically.
Disadvantage: colony needs to be growing on plated media
75
Sabourads media
Used for primary culturing of the specimen,
| SDA with 15% NaCl is used in ID of dematiaceous fungi
76
PDA media
primary culture media. Can stimulate conidia production
77
IMA media
Inhibitory mold agar contains chlorampheniol or gentamicin to inhibit bacterial contamination. Often primary media
78
BHI media
Used for fastidious fungal organisms specifically Histoplasma capsulatum & Blactomyces dermatitidis.
Antibiotics are added to inhibit bacterial NF
79
Corn meal media
Used to differentiate the different species of Candida
80
Mycosel media
Selective media used in the primary isolation of fungal organisms. Contains both chloramphenicol & cycloheximide to inhibit bacterial & fungal contaminates
81
Dimorphic
Fungal organisms that have two distinct morphological forms. Mold @ room temp & yeast @ body temp
82
Blastomyces dermatitidis macroscopic
Produces a downy white/beige colony @ 25 degrees and a creamy/granular white/beige @ 37
83
Blastomyces derematitidis microscopic
25: produces aleuiospores that have single conidia on short stalks (lollipops)
37: produces a yeast cell that hwn budding, it appears to have a broad base
84
Blastomyces dermatitidis clinical significance
Endemic to Mississippi, Ohio, & Missouri River Valleys. Inhaled into the lungs where it causes the primary infection, secondary infections occur in bones, skin, & disseminate
85
Blastomyces dermatitidis other
Inhibited by cycloheximide. Differentiate from Chrysosporium and Scedosporium
86
Coccidioides species macroscopic
25: waxy to felt white/gray. some colonies turn reddish or pink
37: No growth
87
Coccidioides species microscopic
Both 25 & 37: athroconidia that are barrel shaped, smooth, thick walled, alternating disjuncture cells
88
Coccidioides species clinical significance
Found in alkaline soil in San Joaquin valley (C. immitis)
C. posadasii found in desert of Mexico & south America.
Produces a range of disease from lung infecctions to systemic mycosis that can be fatal
89
Coccidioides species other
Ability to grown in presence of cycloheximide.
90
Histoplasma Capsulatum macroscopic
25: wooly, white/brown colony
37: creamy/waxy cream to brown colony
91
Histoplasma capsulatum microscopic
25: macroconidia & microconidia considered aleuiospores. Macroconidia have single conidia that are spiny or tuberculated, produced on short stalks
37: yeast cell that when budding, appears to have a narrow base
92
Histoplasma capsulatum clinical significance
Found in soil contaiminated by bird or bat droppings of the Mississipppi & Ohio River Valley, or seen worldwide.
Pulmonary infections, lung infections, systemic mycosis
93
Histoplasma capsulatum other
Inhibited by Cycloheximide
94
Paracoccidioides brasillensis macroscopic
25: glabrous to velvety, white/buff colony
37: creamy/waxy white to cream colony
95
Paracoccidioides brasillensis microscopic
25: hyphae with chlamydospores
37: pear shaped yeast cells with multiple thin-necked round budding, "shipweels"
96
Paracoccidioides brasillensis clinical signifance
Found in soil in Mexico, but most prevalent in South America (Brazil)
Lung infections but can disseminate
97
Paracoccidioides brasillensis other
inhibited by cycloheximide
98
Penicillium marneffei macro
25: flat, powdery to velvet, tab with blue green center and the reverse becomes red
37: soft white to tan yeast-like colony
99
Penicillium marneffei micro
25: structures typical of the genus Penicillum
37: arthroconidial yeast like cells that are ellipsoidal that have prominent disjuncture between spores
100
Penicillium marneffei clinical significance
Endemic to East & South East Asia.
| Start as lung infection but can infect bone marrow & other organs in immunocompromised. Disseminates in HIV patients
101
Caffic acid test
Detects phnoloxidase similar to bird seed agar.
102
Caffic acid test positive
Cryptococcus neoformans
103
Candida albicans
Usually normal flora of the GI tract, produces a germ tube, positive for both Beta-galactosamidase & I-proline aminopeptidase
104
Candida glabrate
Usually normal flora, commonly isolated from fungal urinary tract infections
105
Candida tropicalis
Often isolated from patients with leukemia
106
Candida parasilosis
Causes endocarditis, otitis externa, nail infections
107
Candida krusei
Colonies are spready on SCA, rare cause of endocarditis
108
Candida dubliniensis
Often seen in oral candidiasis in HIV patients
109
Germ tube test
In a 12x7b test tube, place 1 mL of fetal bovine or rabbit serum. Inoculate with yeast colonies & incubate at 37 degrees for no longer than 3 hrs. Read microscopically for the presence of a germ tube
110
Dalmau method
Used to enhance the microscopic morphology of yeast. Suspected organism is inoculated on Cornmeal Tween 80 agar, cover slipped and observed microscopically after 3 days of incubation
111
Assimilation
Detects the organisms ability to utilize carbs as it sole source of carbon by means of assimilation or ammonium sulfate, asparagine, peptone, & urine as source of nitrogen by assimilation. Interpretation; growth or no growth
112
Fermentation
Ability of the fungal organism to utilize carbs by fermentation. Identified by the production of gas
113
Urease
Detects the organism's ability to produce the urease enzyme
114
Rapid enzyme test for Candida albicans
Tests for presence of Beta-galactosamidase, detected by producing a blue fluorescence with woods lamp. I-proline aminopeptidase produce a red color.
Candida albicans only organism +
115
Immunochromatographic membrane test
Utilizes the monoclonal antibodies LID3H8 and 16B1-F10
Candida albicans pos for both
Candida dubliniensis pos for one
116
Candida albicans CHROMagar
light green
117
Candida dubliniensis CHROMagar
dark green
118
Candida tropicalis CHROMagar
Dark blue
119
Candida kruzsei CHROMagar
Rose with white border
120
Candida parapsiosis CHROMagar
white to pale pink
121
candida glabrata CHROMagar
white to pink to violet
