[2S] UNIT 6 Laboratory Diagnosis of Common Fungal Diseases Flashcards

1
Q

Selective media for fungal culture

A

Saboraud Dextrose Agar (SDA)

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2
Q

Primarily used for isolation of Dermatophytes, yeasts and various other pathogenic and non-pathogenic fungi

A

Saboraud Dextrose Agar (SDA)

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3
Q

Example of fungus for SDA

A

Penicillium globrum
Sporothrix schenkii

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4
Q

SDA Components

A

Peptone & Dextrose

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5
Q

SDA

Source of amino acids and nitrogenous
compounds

A

Peptone

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6
Q

SDA

Source of carbon and energy

A

Dextrose (glucose)

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7
Q

SDA pH & temp

A

5.6 at 25C

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8
Q

French Physician that first formulated SDA

A

Dr Raymond Jacques Adrien Sabouraud

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9
Q

Frequently used microbial growth media for cultivation of molds, yeasts and other fungi

A

POTATO DEXTROSE AGAR (PDA)

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9
Q

Fungus for PDA

A

Aspergillus flavus
Penicillium chrysogenum

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9
Q

General-purpose medium for yeasts and molds

A

POTATO DEXTROSE AGAR (PDA)

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10
Q

Carbohydrate source: support luxuriant growth of fungi and bacteria

A

Potato infusion and dextrose

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11
Q

Encourage mold sporulation and pigment production

A

Potato infusion and dextrose

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12
Q

Supplemented with selective agents to inhibit growth of bacteria

A

POTATO DEXTROSE AGAR (PDA)

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12
Q

2 Selective agents which inhibit the growth of bacteria in PDA

A

o Acids : tartaric acid
o Antibiotics : chloramphenicol or chlortetracycline

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13
Q

Highly nutritious base that meets growth requirements
o Bacteria, yeast, molds

A

BRAIN HEART INFUSION (BHI) AGAR

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13
Q

General purpose medium

A

BHI & PDA AGAR

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14
Q

Isolation, cultivation, and maintenance of fastidious and non-fastidious organisms

A

BRAIN HEART INFUSION (BHI) AGAR

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15
Q

Selective formulation containing chloramphenicol and cycloheximide

A

BRAIN HEART INFUSION (BHI) AGAR

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16
Q

Allow pathogenic fungi while inhibiting a wide range of bacteria and saprophytic fungi

A

BHI: Chloramphenicol & Cycloheximide

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17
Q

____ (Water Agar) – contains agar
o Solidifying agent and purified deionized water

A

1.5%

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17
Q

Recommended for enumeration, cultivation and observation of sporulation of some fungi

A

Water Agar

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18
Q

General appearance : granular to wooly/cottony

A

MICROSPORUM SPP.

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19
Q

Color : Varies from yellow, white and brown
- Certain strains : excuse a cream color

A

MICROSPORUM SPP.

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20
Q

ID CONIDIA & SPECIE

Hyaline, multi-septate, with thick rough cell walls, and are clavate, fusiform or spindle- shaped

A

Microsporum spp. Macroconidia

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21
Q

MICROSPORUM SPP. ID CONIDIA & SPECIE

Absent or rarely found

A

Microsporum audoinii Macroconidia

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21
Q

MICROSPORUM SPP.

have a longer appearance than Microsporum canis

A

MICROSPORUM AUDOINII

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21
Q

MICROSPORUM SPP.

Chlamydospores : Most cultures are sterile or produce only the thick-walled chlamydospores (Chlamydoconidium)

A

MICROSPORUM AUDOINII

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22
Q

ID CONIDIA & SPECIE

Single-cell, hyaline, smooth- walled, and are predominantly clavate in shape

A

Microsporum spp. Microconidia

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23
Q

MICROSPORUM SPP. CONFIRMATORY TEST

Salmon Pink to Pinkish Brown

A

Microsporum audoinii

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23
Q

MICROSPORUM SPP. ID CONIDIA & SPECIE

Pyriform to clavate

A

Microsporum audoinii & Microsporum canis Microconidia

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24
Q

MICROSPORUM SPP. CONFIRMATORY TEST

No growth on rice grains

A

Microsporum audoinii

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25
Q

MICROSPORUM SPP. CONFIRMATORY TEST

Reverse Pigmentation on Potato Dextrose Agar (PDA) - Salmon Pink to Pinkish Brown

A

Microsporum audoinii

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26
Q

MICROSPORUM SPP. CONFIRMATORY TEST

Demonstrates rapid pH change to alkaline (purple coloration)

A

BCP Milk Solids Glucose Agar on Microsporum audoinii

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27
Q

MICROSPORUM SPP. CONFIRMATORY TEST

Hair Perforation Test Negative

A

Microsporum audoinii

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28
Q

MICROSPORUM SPP. CONFIRMATORY TEST

Reverse Pigmentation on PDA - Bright Yellow

A

Microsporum canis

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28
Q

MICROSPORUM SPP. ID CONIDIA & SPECIE

Spindle shaped (5-15 cells), verrucose, thick-walled and have terminal knobs

A

MICROSPORUM CANIS MACROCONIDIA

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29
Q

MICROSPORUM SPP. CONFIRMATORY TEST

Good growth on rice grains

A

Microsporum canis

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30
Q

MICROSPORUM SPP. CONFIRMATORY TEST

Positive Hair Perforation Test

A

Microsporum canis

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30
Q

MICROSPORUM SPP.

No macroconidia and microconidia

A

Microsporum ferrugineum

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31
Q

MICROSPORUM SPP.

“bamboo” hyphae

A

Microsporum ferrugineum

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32
Q

MICROSPORUM SPP.

Visualization : confirms this species and the other specific colonial features of the Microsporum genus

A

Microsporum ferrugineum

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33
Q

Epidermophyton that is clinically significant affecting humans

A

Epidermophyton floccosum

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34
Q

Colonial characteristics on Culture Medium: Older cultures : white pleomorphic tufts of mycelium

A

EPIDERMOPHYTON

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34
Q

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

A

EPIDERMOPHYTON

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35
Q

Colonial characteristics on Culture Medium: A deep yellowish-brown reverse pigment

A

EPIDERMOPHYTON

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36
Q
  • Microscopic features
    o Smooth, thin-walled macroconidia: often produced in clusters growing directly from the hyphae
A

EPIDERMOPHYTON

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37
Q
  • Microscopic features
    o Numerous chlamydospores are formed in older
    o Microconidia : absent
A

EPIDERMOPHYTON

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38
Q

TRICHOSPORON SPP.

  • Colonial characteristics :
    o White to cream-coloured, powdery, suede-like to farinose with radial furrows and irregular folds
A

Trichosporon asahii

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39
Q

TRICHOSPORON SPP.

  • Microscopic Morphology
    o Budding cells and lateral conidia are absent
    o Arthroconidia : barrel-shaped
A

Trichosporon asahii

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40
Q

TRICHOSPORON SPP.

  • Laboratory Diagnosis
    o Species assimilates L-arabinose but not melibiose
    o Growth at 37C
A

Trichosporon asahii

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41
Q

TRICHOSPORON SPP.

Most common species from invasive infections

A

Trichosporon asahii

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42
Q

TRICHOSPORON SPP.

*Colonial characteristics :
o Restricted, white, finely cerebriform with a granular covering, without marginal zone, often cracking the media

A

Trichosporon inkin

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43
Q

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

A

Trichosporon inkin

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43
Q

TRICHOSPORON SPP.

Microscopic Morphology
o Budding cells and lateral conidia are absent
o Arthroconidia : long and cylindrical

A

Trichosporon inkin

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44
Q

TRICHOSPORON SPP.

Laboratory Diagnosis:
o Associated with white piedra on pubic hairs

A

Trichosporon inkin

45
Q

Other associated terms for Malassezia furfur

A

Tinea versicolor
Pityriasis versicolor
Dermatomycosis furfuracea
Tinea flava
Chromophytosis

46
Q

Laboratory Diagnosis
o KOH/PAS : preparation of skin scrapings

A

Malassezia furfur

47
Q

ODD ONE OUT: MALASSEZIA FURFUR

Tinea versicolor
Tinea nigra palmaris
Pityriasis versicolor
Dermatomycosis furfuracea
Tinea flava
Chromophytosis

A

Tinea nigra palmaris - Hortaea werneckii

48
Q

Laboratory Diagnosis
o Wood’s lamp = golden yellow to light green fluorescence in lesions/hair

A

Malassezia furfur

49
Q

Microscopic examination:
- PAS: spaghetti and meatball appearance

A

Malassezia furfur

49
Q

Microscopic examination:
- KOH test: Round budding yeast cells with hyphae

A

Malassezia furfur

50
Q

Culture :
- Saboraud’s Dextrose Agar (SDA): overlaid with Olive, Peanut, or Vegetable oil due to their affinity to lipids (lipophilic)

A

Malassezia furfur

51
Q

Culture :
o Macroscopic : Dry, smooth or lightly wrinkled, glistening or dull, white to creamy

A

Malassezia furfur

52
Q

Culture :
o Microscopic : Presence of collarettes during conidiogenesis

A

Malassezia furfur

53
Q

Laboratory Diagnosis :
o Specimen: Skin scrapings from darkly pigmented lesions
o Direct Microscopic Examination:
- 10-20% KOH test: Septate hyphal elements and budding cells

A

Hortaea werneckii

53
Q

ODD ONE OUT: HORTAEA WERNECKII

Tinea nigra palmaris
Exophiala werneckii
Chromophytosis
Phaeoannellomyces werneckii
Cladosporium werneckii

A

Chromophytosis - Malassezia furfur

54
Q

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

A

Hortaea werneckii

55
Q

Microscopic examination:
o Young cultures: Budding blastoconidia
o Old cultures: Cluster of blastoconidia
o Older hyphal colonies: Annelloconidia

A

Hortaea werneckii

56
Q

Hortaea werneckii on old cultures

A

Cluster of blastoconidia

56
Q

Hortaea werneckii on young cultures

A

Budding blastoconidia

57
Q

Hortaea werneckii on older hyphal colonies

A

Annelloconidia

58
Q

Causative Agent : chromoblastomycosis

A

PHIALOPHORA SPP.

58
Q

Phialophora spp type of mycoses

A

Subcutaneous

59
Q

characterized as verrucous nodules that often become ulcerated and crusted

A

Phialophora spp.

60
Q

Diagnosis: Presence of characteristic lesions accompanied by microscopic sclerotic bodies
o Copper pennies – shape and staining properties in tissue sections

A

PHIALOPHORA SPP.

60
Q

Laboratory Diagnosis Methods
o Growth : rapid growing producing olive-gray to black cottony or wooly colonies

A

PHIALOPHORA SPP.

61
Q

Microscopy : Conidiogenous cells, phaeoid, flask-shaped phialides, with collarettes

A

PHIALOPHORA SPP.

62
Q

Fusarium spp type of mycoses

A

Cutaneous (Associated with mycotic keratitis)

63
Q

Second most common pathogenic moulds – invasive disease

A

Fusarium spp.

64
Q

Diagnosis: Implicated in a number of infectious diseases :
o Keratomycosis
o Burn wounds
o Invasive disease in immunocompromised patients

A

Fusarium spp.

65
Q

Laboratory Diagnosis Methods :
o Isolation : via Blood culture
- may appear yeast-like on initial recovery

A

Fusarium spp.

65
Q

o Microscopy : banana- or canoe-shaped formed singly, in small clusters or clustered together called as sporodochia + multicelled

A

Fusarium spp. macroconidia

66
Q

Microscopy : abundant macroconidia with fewer microconidia are produced on vegetative hyphae

A

Fusarium spp.

66
Q

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

A

Fusarium spp.

67
Q

FUSARIUM SPP MACROCONIDIA

banana- or canoe-shaped formed singly, in small clusters or clustered together

A

Sporodochia

68
Q

Genus of ascomycetes fungi that have an unbranched stalk like conidiophores

A

Aspergillus

69
Q

Genus of ascomycetes that have a brush-like conidiophore

A

Penicillium

70
Q

ASPERGILLUS & PENICILLIUM

Green and black; yellow to brown

A

Aspergillus

71
Q

ASPERGILLUS & PENICILLIUM

Mostly blue

A

Penicillium

72
Q

ASPERGILLUS & PENICILLIUM

Aseptate and unbranched

A

Aspergillus

73
Q

ASPERGILLUS & PENICILLIUM

Arises from a specialized T-shaped thick walled foot cell

A

Aspergillus

74
Q

ASPERGILLUS & PENICILLIUM

Enlarges into a vesicle at its tip

A

Aspergillus

75
Q

ASPERGILLUS & PENICILLIUM

Structure : spherical head

A

Aspergillus

75
Q

ASPERGILLUS & PENICILLIUM

Bears the finger-like sterigmata

A

Aspergillus

76
Q

ASPERGILLUS & PENICILLIUM

Long slender septate and branched

A

Penicillium

77
Q

ASPERGILLUS & PENICILLIUM

Arises from any vegetative cell of the mycelium

A

Penicillium

78
Q

ASPERGILLUS & PENICILLIUM

No foot cell

A

Penicillium

79
Q

ASPERGILLUS & PENICILLIUM

Ends in a whorl of branches = broom- like appearance

A

Penicillium

80
Q

ASPERGILLUS & PENICILLIUM

Disease causing ability is high

A

Aspergillus

81
Q

ASPERGILLUS & PENICILLIUM

Disease causing ability is low

A

Penicillium

82
Q

ASPERGILLUS & PENICILLIUM

Antibiotic Production is not popular

A

Aspergillus

83
Q

ASPERGILLUS & PENICILLIUM

Antibiotic Production is popular

A

Penicillium

84
Q

Bread mold

A

Rhizopus

85
Q

Disease : Histoplasmosis

A

HISTOPLASMA CAPSULATUM

86
Q

MOT of HISTOPLASMA CAPSULATUM

A

Inhalation of Conidia

87
Q

PATHOGENESIS

An intracellular mycosis of the reticuloendothelial system infection is self-limited

A

Histoplasma capsulatum

88
Q

ODD ONE OUT: PATHOGENESIS OF HISTOPLASMOSIS

fever
chills
myalgias
headaches
malaise
non-productive cough

A

malaise

88
Q

PATHOGENESIS

Severe disseminated histoplasmosis
- RES involved, with lymphadenopathy, enlarged spleen, liver, high fever, anemia

A

Histoplasma capsulatum

89
Q

Colony characteristics
o Cultivation in SDA - white to tan cottony colonies; pale- yellow brown on reverse

A

Histoplasma capsulatum

90
Q

Specimen for Diagnosis : Sputum, Urine, Scrappings from lesions, Bone Marrow biopsy, Skin, Lymph nodes

A

Histoplasma capsulatum

91
Q

Morphology : small, ovoid cells intracellularly in histologic section stained with Gomori methanamine silver or Giemsa stain

A

Histoplasma capsulatum

92
Q

ID CONIDIA & SPECIE

o Thick-walled spherical structures
o 8-15 pm diameter with surface projections

A

Histoplasma capsulatum macroconidia

93
Q

Miscellaneous test
o Serological tests : immunodiffusion, latex agglutination test

A

Histoplasma capsulatum

94
Q

PATHOGENESIS

o Infection is self-limited
o dissemination is rare but maybe fatal

A

Coccodioides immitis

94
Q

ID CONIDIA & SPECIE

o Smooth spherical structures
o 2-4 um in diameter

A

Histoplasma capsulatum microconidia

95
Q

Treatment for Histoplasmosis

A

Amphotericin B

96
Q

Disease : Coccidioidomycosis

A

Coccodioides immitis

97
Q

MOT of Coccodioides immitis

A

Inhalation of airborne arthroconidia

98
Q

PATHOGENESIS

o patients with primary infection are asymptomatic
o S/S: fever, malaise, cough, headache

A

Coccodioides immitis

99
Q

PATHOGENESIS

late stage patient forms a hypersensitivity reaction in the form of erythema nodosum or erythema multiforme (rashes)

A

Coccodioides immitis

100
Q

Coccodioides immitis in SDA

A

white to tan colonies

101
Q

spherule with thick, doubly refractile wall and endospores form within the spherule and fill it

A

Coccodioides immitis

102
Q

o Globose macroconidia
o 8-15 um
o with distinctive tuberculate or finger-like cell wall ornamentation

A

Coccodioides immitis macroconidia

103
Q

o Ovoid microconidia
o 2-4um
o which appear smooth or finely roughened

A

Coccodioides immitis microconidia

103
Q

Serological tests for Coccodioides immitis

A

immunodiffusion, latex agglutination test

104
Q

ODD ONE OUT: COCCODIOIDES SPECIMEN

Sputum
Pus
CSF
Lymph Node
Tissue Biopsy

A

Lymph Node - Histoplasmosis

105
Q

MACROSCOPIC MORPHOLOGY (22C)

Slow to moderate growth

A

Blastomyces dermatitidis

106
Q

MACROSCOPIC MORPHOLOGY (22C)

White to dark tan young colonies tenacious

A

Blastomyces dermatitidis

107
Q

MACROSCOPIC MORPHOLOGY (22C)

Old colonies elabrous to woolly

A

Blastomyces dermatitidis

108
Q

MICROSCOPIC MORPHOLOGY (BAP AT 37C)

  • Large yeast (8-12 um)
  • Blastoconidia : attached by broad base, small, oval yeast (2-5 um)
A

Blastomyces dermatitidis

109
Q

MICROSCOPIC MORPHOLOGY (22C)

Oval, pyriform to globose smooth conidia borne
o on short, lateral hypha like conidiophores

A

Blastomyces dermatitidis

110
Q

MACROSCOPIC MORPHOLOGY (22C)

  • Slow growth
  • White to beige
A

Paracoccidioides brasiliensis

110
Q

Agar for Blastomycosis dermatitidis

A

BAP

111
Q

MACROSCOPIC MORPHOLOGY (22C)

  • Colony glabrous, leathery,
  • flat to wrinkled, folded or velvety
A

Paracoccidioides brasiliensis

112
Q

MICROSCOPIC MORPHOLOGY (22C)

Colonies : only produce sterile hyphae

A

Paracoccidioides brasiliensis

113
Q

MICROSCOPIC MORPHOLOGY (22C)

Fresh isolates : produce conidia similar to those of B. dermatitidis

A

Paracoccidioides brasiliensis

114
Q

MICROSCOPIC MORPHOLOGY (BHI AT 37C)

Multiple blastoconidia budding from single, large yeast (15-30 um)

A

Paracoccidioides brasiliensis

115
Q

Agar for Paracoccidioides brasiliensis

A

BHI