[2S] UNIT 6 Laboratory Diagnosis of Common Fungal Diseases Flashcards
(139 cards)
1
Q
Selective media for fungal culture
A
Saboraud Dextrose Agar (SDA)
2
Q
Primarily used for isolation of Dermatophytes, yeasts and various other pathogenic and non-pathogenic fungi
A
Saboraud Dextrose Agar (SDA)
3
Q
Example of fungus for SDA
A
Penicillium globrum
Sporothrix schenkii
4
Q
SDA Components
A
Peptone & Dextrose
5
Q
SDA
Source of amino acids and nitrogenous
compounds
A
Peptone
6
Q
SDA
Source of carbon and energy
A
Dextrose (glucose)
7
Q
SDA pH & temp
A
5.6 at 25C
8
Q
French Physician that first formulated SDA
A
Dr Raymond Jacques Adrien Sabouraud
9
Q
Frequently used microbial growth media for cultivation of molds, yeasts and other fungi
A
POTATO DEXTROSE AGAR (PDA)
9
Q
Fungus for PDA
A
Aspergillus flavus
Penicillium chrysogenum
9
Q
General-purpose medium for yeasts and molds
A
POTATO DEXTROSE AGAR (PDA)
10
Q
Carbohydrate source: support luxuriant growth of fungi and bacteria
A
Potato infusion and dextrose
11
Q
Encourage mold sporulation and pigment production
A
Potato infusion and dextrose
12
Q
Supplemented with selective agents to inhibit growth of bacteria
A
POTATO DEXTROSE AGAR (PDA)
12
Q
2 Selective agents which inhibit the growth of bacteria in PDA
A
o Acids : tartaric acid
o Antibiotics : chloramphenicol or chlortetracycline
13
Q
Highly nutritious base that meets growth requirements
o Bacteria, yeast, molds
A
BRAIN HEART INFUSION (BHI) AGAR
13
Q
General purpose medium
A
BHI & PDA AGAR
14
Q
Isolation, cultivation, and maintenance of fastidious and non-fastidious organisms
A
BRAIN HEART INFUSION (BHI) AGAR
15
Q
Selective formulation containing chloramphenicol and cycloheximide
A
BRAIN HEART INFUSION (BHI) AGAR
16
Q
Allow pathogenic fungi while inhibiting a wide range of bacteria and saprophytic fungi
A
BHI: Chloramphenicol & Cycloheximide
17
Q
____ (Water Agar) – contains agar
o Solidifying agent and purified deionized water
A
1.5%
17
Q
Recommended for enumeration, cultivation and observation of sporulation of some fungi
A
Water Agar
18
Q
General appearance : granular to wooly/cottony
A
MICROSPORUM SPP.
19
Q
Color : Varies from yellow, white and brown
- Certain strains : excuse a cream color
A
MICROSPORUM SPP.
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ID CONIDIA & SPECIE
Hyaline, multi-septate, with thick rough cell walls, and are clavate, fusiform or spindle- shaped
Microsporum spp. Macroconidia
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MICROSPORUM SPP. ID CONIDIA & SPECIE
Absent or rarely found
Microsporum audoinii Macroconidia
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MICROSPORUM SPP.
have a longer appearance than Microsporum canis
MICROSPORUM AUDOINII
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MICROSPORUM SPP.
Chlamydospores : Most cultures are sterile or produce only the thick-walled chlamydospores (Chlamydoconidium)
MICROSPORUM AUDOINII
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ID CONIDIA & SPECIE
Single-cell, hyaline, smooth- walled, and are predominantly clavate in shape
Microsporum spp. Microconidia
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MICROSPORUM SPP. CONFIRMATORY TEST
Salmon Pink to Pinkish Brown
Microsporum audoinii
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MICROSPORUM SPP. ID CONIDIA & SPECIE
Pyriform to clavate
Microsporum audoinii & Microsporum canis Microconidia
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MICROSPORUM SPP. CONFIRMATORY TEST
No growth on rice grains
Microsporum audoinii
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MICROSPORUM SPP. CONFIRMATORY TEST
Reverse Pigmentation on Potato Dextrose Agar (PDA) - Salmon Pink to Pinkish Brown
Microsporum audoinii
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MICROSPORUM SPP. CONFIRMATORY TEST
Demonstrates rapid pH change to alkaline (purple coloration)
BCP Milk Solids Glucose Agar on Microsporum audoinii
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MICROSPORUM SPP. CONFIRMATORY TEST
Hair Perforation Test Negative
Microsporum audoinii
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MICROSPORUM SPP. CONFIRMATORY TEST
Reverse Pigmentation on PDA - Bright Yellow
Microsporum canis
28
MICROSPORUM SPP. ID CONIDIA & SPECIE
Spindle shaped (5-15 cells), verrucose, thick-walled and have terminal knobs
MICROSPORUM CANIS MACROCONIDIA
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MICROSPORUM SPP. CONFIRMATORY TEST
Good growth on rice grains
Microsporum canis
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MICROSPORUM SPP. CONFIRMATORY TEST
Positive Hair Perforation Test
Microsporum canis
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MICROSPORUM SPP.
No macroconidia and microconidia
Microsporum ferrugineum
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MICROSPORUM SPP.
"bamboo" hyphae
Microsporum ferrugineum
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MICROSPORUM SPP.
Visualization : confirms this species and the other specific colonial features of the Microsporum genus
Microsporum ferrugineum
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Epidermophyton that is clinically significant affecting humans
Epidermophyton floccosum
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Colonial characteristics on Culture Medium: Older cultures : white pleomorphic tufts of mycelium
EPIDERMOPHYTON
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Colonial characteristics on Culture Medium: Greenish-brown with a suede-like surface, raised and folded in the center, with a flat periphery merged fringe of growth
EPIDERMOPHYTON
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Colonial characteristics on Culture Medium: A deep yellowish-brown reverse pigment
EPIDERMOPHYTON
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* Microscopic features
o Smooth, thin-walled macroconidia: often produced in clusters growing directly from the hyphae
EPIDERMOPHYTON
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* Microscopic features
o Numerous chlamydospores are formed in older
o Microconidia : absent
EPIDERMOPHYTON
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TRICHOSPORON SPP.
* Colonial characteristics :
o White to cream-coloured, powdery, suede-like to farinose with radial furrows and irregular folds
Trichosporon asahii
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TRICHOSPORON SPP.
* Microscopic Morphology
o Budding cells and lateral conidia are absent
o Arthroconidia : barrel-shaped
Trichosporon asahii
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TRICHOSPORON SPP.
* Laboratory Diagnosis
o Species assimilates L-arabinose but not melibiose
o Growth at 37C
Trichosporon asahii
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TRICHOSPORON SPP.
Most common species from invasive infections
Trichosporon asahii
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TRICHOSPORON SPP.
*Colonial characteristics :
o Restricted, white, finely cerebriform with a granular covering, without marginal zone, often cracking the media
Trichosporon inkin
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TRICHOSPORON SPP.
Laboratory Diagnosis
o Species assimilates myo-inositol but not melibiose and is tolerant to 0.01% (variable tolerance to 0.1%) cycloheximide
o Growth at 37C
Trichosporon inkin
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TRICHOSPORON SPP.
Microscopic Morphology
o Budding cells and lateral conidia are absent
o Arthroconidia : long and cylindrical
Trichosporon inkin
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TRICHOSPORON SPP.
Laboratory Diagnosis:
o Associated with white piedra on pubic hairs
Trichosporon inkin
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Other associated terms for Malassezia furfur
Tinea versicolor
Pityriasis versicolor
Dermatomycosis furfuracea
Tinea flava
Chromophytosis
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Laboratory Diagnosis
o KOH/PAS : preparation of skin scrapings
Malassezia furfur
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ODD ONE OUT: MALASSEZIA FURFUR
Tinea versicolor
Tinea nigra palmaris
Pityriasis versicolor
Dermatomycosis furfuracea
Tinea flava
Chromophytosis
Tinea nigra palmaris - Hortaea werneckii
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Laboratory Diagnosis
o Wood's lamp = golden yellow to light green fluorescence in lesions/hair
Malassezia furfur
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Microscopic examination:
- PAS: spaghetti and meatball appearance
Malassezia furfur
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Microscopic examination:
- KOH test: Round budding yeast cells with hyphae
Malassezia furfur
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Culture :
- Saboraud's Dextrose Agar (SDA): overlaid with Olive, Peanut, or Vegetable oil due to their affinity to lipids (lipophilic)
Malassezia furfur
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Culture :
o Macroscopic : Dry, smooth or lightly wrinkled, glistening or dull, white to creamy
Malassezia furfur
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Culture :
o Microscopic : Presence of collarettes during conidiogenesis
Malassezia furfur
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Laboratory Diagnosis :
o Specimen: Skin scrapings from darkly pigmented lesions
o Direct Microscopic Examination:
- 10-20% KOH test: Septate hyphal elements and budding cells
Hortaea werneckii
53
ODD ONE OUT: HORTAEA WERNECKII
Tinea nigra palmaris
Exophiala werneckii
Chromophytosis
Phaeoannellomyces werneckii
Cladosporium werneckii
Chromophytosis - Malassezia furfur
54
Culture:
o SDA with antibiotics (e.g. Chloramphenicol/Gentamicin) at 37°C
o Colonies: shiny, moist, yeast-like, dirty white-brown coloration.
- colonies eventually turn to OLIVE to GREENISH BLACK
Hortaea werneckii
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Microscopic examination:
o Young cultures: Budding blastoconidia
o Old cultures: Cluster of blastoconidia
o Older hyphal colonies: Annelloconidia
Hortaea werneckii
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Hortaea werneckii on old cultures
Cluster of blastoconidia
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Hortaea werneckii on young cultures
Budding blastoconidia
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Hortaea werneckii on older hyphal colonies
Annelloconidia
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Causative Agent : chromoblastomycosis
PHIALOPHORA SPP.
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Phialophora spp type of mycoses
Subcutaneous
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characterized as verrucous nodules that often become ulcerated and crusted
Phialophora spp.
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Diagnosis: Presence of characteristic lesions accompanied by microscopic sclerotic bodies
o Copper pennies – shape and staining properties in tissue sections
PHIALOPHORA SPP.
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Laboratory Diagnosis Methods
o Growth : rapid growing producing olive-gray to black cottony or wooly colonies
PHIALOPHORA SPP.
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Microscopy : Conidiogenous cells, phaeoid, flask-shaped phialides, with collarettes
PHIALOPHORA SPP.
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Fusarium spp type of mycoses
Cutaneous (Associated with mycotic keratitis)
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Second most common pathogenic moulds – invasive disease
Fusarium spp.
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Diagnosis: Implicated in a number of infectious diseases :
o Keratomycosis
o Burn wounds
o Invasive disease in immunocompromised patients
Fusarium spp.
65
Laboratory Diagnosis Methods :
o Isolation : via Blood culture
- may appear yeast-like on initial recovery
Fusarium spp.
65
o Microscopy : banana- or canoe-shaped formed singly, in small clusters or clustered together called as sporodochia + multicelled
Fusarium spp. macroconidia
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Microscopy : abundant macroconidia with fewer microconidia are produced on vegetative hyphae
Fusarium spp.
66
Laboratory Diagnosis Methods
o Growth : rapidly growing hyaline fungus producing a fluffy aerial mycelium
- develop various colors with age, ranging from rose to mauve to purple to yellow as well as pink, lavender or salmon color
- Diffusible pigments
Fusarium spp.
67
FUSARIUM SPP MACROCONIDIA
banana- or canoe-shaped formed singly, in small clusters or clustered together
Sporodochia
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Genus of ascomycetes fungi that have an unbranched stalk like conidiophores
Aspergillus
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Genus of ascomycetes that have a brush-like conidiophore
Penicillium
70
ASPERGILLUS & PENICILLIUM
Green and black; yellow to brown
Aspergillus
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ASPERGILLUS & PENICILLIUM
Mostly blue
Penicillium
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ASPERGILLUS & PENICILLIUM
Aseptate and unbranched
Aspergillus
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ASPERGILLUS & PENICILLIUM
Arises from a specialized T-shaped thick walled foot cell
Aspergillus
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ASPERGILLUS & PENICILLIUM
Enlarges into a vesicle at its tip
Aspergillus
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ASPERGILLUS & PENICILLIUM
Structure : spherical head
Aspergillus
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ASPERGILLUS & PENICILLIUM
Bears the finger-like sterigmata
Aspergillus
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ASPERGILLUS & PENICILLIUM
Long slender septate and branched
Penicillium
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ASPERGILLUS & PENICILLIUM
Arises from any vegetative cell of the mycelium
Penicillium
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ASPERGILLUS & PENICILLIUM
No foot cell
Penicillium
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ASPERGILLUS & PENICILLIUM
Ends in a whorl of branches = broom- like appearance
Penicillium
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ASPERGILLUS & PENICILLIUM
Disease causing ability is high
Aspergillus
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ASPERGILLUS & PENICILLIUM
Disease causing ability is low
Penicillium
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ASPERGILLUS & PENICILLIUM
Antibiotic Production is not popular
Aspergillus
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ASPERGILLUS & PENICILLIUM
Antibiotic Production is popular
Penicillium
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Bread mold
Rhizopus
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Disease : Histoplasmosis
HISTOPLASMA CAPSULATUM
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MOT of HISTOPLASMA CAPSULATUM
Inhalation of Conidia
87
PATHOGENESIS
An intracellular mycosis of the reticuloendothelial system infection is self-limited
Histoplasma capsulatum
88
ODD ONE OUT: PATHOGENESIS OF HISTOPLASMOSIS
fever
chills
myalgias
headaches
malaise
non-productive cough
malaise
88
PATHOGENESIS
Severe disseminated histoplasmosis
- RES involved, with lymphadenopathy, enlarged spleen, liver, high fever, anemia
Histoplasma capsulatum
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Colony characteristics
o Cultivation in SDA - white to tan cottony colonies; pale- yellow brown on reverse
Histoplasma capsulatum
90
Specimen for Diagnosis : Sputum, Urine, Scrappings from lesions, Bone Marrow biopsy, Skin, Lymph nodes
Histoplasma capsulatum
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Morphology : small, ovoid cells intracellularly in histologic section stained with Gomori methanamine silver or Giemsa stain
Histoplasma capsulatum
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ID CONIDIA & SPECIE
o Thick-walled spherical structures
o 8-15 pm diameter with surface projections
Histoplasma capsulatum macroconidia
93
Miscellaneous test
o Serological tests : immunodiffusion, latex agglutination test
Histoplasma capsulatum
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PATHOGENESIS
o Infection is self-limited
o dissemination is rare but maybe fatal
Coccodioides immitis
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ID CONIDIA & SPECIE
o Smooth spherical structures
o 2-4 um in diameter
Histoplasma capsulatum microconidia
95
Treatment for Histoplasmosis
Amphotericin B
96
Disease : Coccidioidomycosis
Coccodioides immitis
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MOT of Coccodioides immitis
Inhalation of airborne arthroconidia
98
PATHOGENESIS
o patients with primary infection are asymptomatic
o S/S: fever, malaise, cough, headache
Coccodioides immitis
99
PATHOGENESIS
late stage patient forms a hypersensitivity reaction in the form of erythema nodosum or erythema multiforme (rashes)
Coccodioides immitis
100
Coccodioides immitis in SDA
white to tan colonies
101
spherule with thick, doubly refractile wall and endospores form within the spherule and fill it
Coccodioides immitis
102
o Globose macroconidia
o 8-15 um
o with distinctive tuberculate or finger-like cell wall ornamentation
Coccodioides immitis macroconidia
103
o Ovoid microconidia
o 2-4um
o which appear smooth or finely roughened
Coccodioides immitis microconidia
103
Serological tests for Coccodioides immitis
immunodiffusion, latex agglutination test
104
ODD ONE OUT: COCCODIOIDES SPECIMEN
Sputum
Pus
CSF
Lymph Node
Tissue Biopsy
Lymph Node - Histoplasmosis
105
MACROSCOPIC MORPHOLOGY (22C)
Slow to moderate growth
Blastomyces dermatitidis
106
MACROSCOPIC MORPHOLOGY (22C)
White to dark tan young colonies tenacious
Blastomyces dermatitidis
107
MACROSCOPIC MORPHOLOGY (22C)
Old colonies elabrous to woolly
Blastomyces dermatitidis
108
MICROSCOPIC MORPHOLOGY (BAP AT 37C)
* Large yeast (8-12 um)
* Blastoconidia : attached by broad base, small, oval yeast (2-5 um)
Blastomyces dermatitidis
109
MICROSCOPIC MORPHOLOGY (22C)
Oval, pyriform to globose smooth conidia borne
o on short, lateral hypha like conidiophores
Blastomyces dermatitidis
110
MACROSCOPIC MORPHOLOGY (22C)
* Slow growth
* White to beige
Paracoccidioides brasiliensis
110
Agar for Blastomycosis dermatitidis
BAP
111
MACROSCOPIC MORPHOLOGY (22C)
* Colony glabrous, leathery,
* flat to wrinkled, folded or velvety
Paracoccidioides brasiliensis
112
MICROSCOPIC MORPHOLOGY (22C)
Colonies : only produce sterile hyphae
Paracoccidioides brasiliensis
113
MICROSCOPIC MORPHOLOGY (22C)
Fresh isolates : produce conidia similar to those of B. dermatitidis
Paracoccidioides brasiliensis
114
MICROSCOPIC MORPHOLOGY (BHI AT 37C)
Multiple blastoconidia budding from single, large yeast (15-30 um)
Paracoccidioides brasiliensis
115
Agar for Paracoccidioides brasiliensis
BHI
