RQuestions Flashcards
1
Q
All of the following are examples of appropriate specimens for the recovery of fungi except:
A. Tissue biopsy
B. CSF
C. Aspirate of exudate
D. Swab
A
D
2
Q
For which clinical specimens is the KOH direct mount technique for examination of fungal elements used?
A. Skin
B. CSF
C. Blood
D. Bone marrow
A
A
3
Q
The India ink stain is used as a presumptive test for the presence of which organism?
A. Aspergillus niger in blood
B. Cryptococcus neoformans in CSF
C. Histoplasma capsulatum in CSF
D. Candida albicans in blood or body fluids
A
B
4
Q
Cutaneous disease involving skin, hair, and nails usually indicates an infection with a:
A. Dimorphic fungus
B. Dermatophyte
C. Zygomycetes
D. Candida species
A
B
5
Q
. What is the first step to be performed in the identification of an unknown yeast isolate?
A. Gram stain smear
B. India ink stain
C. Catalase test
D. Germ tube test
A
D
6
Q
An isolate produced a constriction that was
interpreted as a positive germ tube, but Candida albicans was ruled out when confirmatory tests were performed. Which of the following fungi is the most likely identification?
A. Candida tropicalis
B. Cryptococcus neoformans
C. Candida glabrata
D. Rhodotorula rubra
A
A
7
Q
Cornmeal agar with Tween 80 is used to identify which characteristic of an unknown yeast isolate?
A. Hyphae (true and pseudo)
B. Blastoconidia and arthroconidia
C. Chlamydospores
D. All of these options
A
D
8
Q
Blastoconidia are the beginning of which structures?
A. Arthroconidia
B. Germ tubes
C. Pseudohyphae
D. True hyphae
A
C
9
Q
An isolate from CSF growing on cornmeal agar produces the following structures:
Blastoconidia = + Pseudohyphae = Neg Chlamydospores = Neg Arthroconidia= Neg
Which tests should be performed next? A. Birdseed agar and urease B. Germ tube and glucose C. India ink and germ tube D. All of these options
A
A
10
Q
Which of the following yeast enzymes is detected using birdseed (niger seed) agar?
A. Phenol oxidase
B. Catalase
C. Urease
D. Nitrate reductase
A
A
11
Q
Which of the following yeasts is characteristically positive for germ tube production?
A. Candida tropicalis
B. Candida kefyr (pseudotropicalis)
C. Cryptococcus neoformans
D. Candida albicans
A
D
12
Q
Arthroconidia production is used to differentiate which two yeast isolates?
A. Candida albicans and Candida dubliniensis
B. Trichosporon cutaneum and Cryptococcus neoformans
C. Candida albicans and Candida tropicalis
D. Saccharomyces cerevisiae and Candida glabrata
A
B
13
Q
The urease test, niger seed agar test, and the germ
tube test are all used for the presumptive identification of:
A. Rhodotorula rubra
B. Cryptococcus neoformans
C. Trichosporon cutaneum
D. Candida albicans
A
B
14
Q
Which of the following yeasts produces only blastoconidia on cornmeal Tween 80 agar?
A. Candida spp.
B. Trichosporon spp.
C. Geotrichum spp.
D. Cryptococcus spp
A
D
15
Q
Ascospores are formed by which yeast isolate?
A. Saccharomyces cerevisiae
B. Candida albicans
C. Cryptococ cus neoformans
D. All of these options
A
A.
16
Q
A germ tube–negative, pink yeast isolate was recovered from the respiratory secretions and urine of a patient with AIDS. Given the following results, what is the most likely identification? CORNMEAL TWEEN 80 AGAR Blastoconidia = + Pseudohyphae = Neg Arthroconidia= Neg Urease = +
A. Candida albicans
B. Rhodotorula spp.
C. Cryptococcus spp.
D. Trichosporon spp.
A
B
17
Q
Chlamydospore production is demonstrated by which Candida species?
A. C. glabrata
B. C. krusei
C. C. albicans
D. C. tropicalis
A
C
18
Q
Carbohydrate assimilation tests are used for the identification of yeast isolates by inoculating
media:
A. Free of carbohydrates
B. Free of niger seed
C. Containing carbohydrates
D. Containing yeast extract
A
A
19
Q
Yeast recovered from the urine of a catheterized patient receiving chemotherapy for cancer gave the following results: CORNMEAL TWEEN 80 AGAR Germ tube = + Blastoconidia = + Pseudohyphae = + Arthroconidia= Neg Chlamydospores = +
What further testing is necessary?
A. Carbohydrate assimilation and urease
B. Urease and niger seed
C. Nitrate reductase and carbohydrate fermentation
D. No further testing is needed for identification
A
D
20
Q
A blood agar plate inoculated with sputum from a patient with diabetes mellitus grew very few
bacterial flora and a predominance of yeast.
Given the following results, what is the most likely identification of the yeast isolate?
CORNMEAL TWEEN 80 AGAR
Germ tube = Neg Pseudohyphae = +
Arthroconidia = Neg Blastoconidia = + (arranged
along pseudohyphae)
Chlamydospores = Neg
A. Candida tropicalis
B. Candida kefyr (pseudotropicalis)
C. Trichosporon cutaneum
D. Geotrichum candidum
A
A
21
Q
Dimorphic molds are found in infected tissue in which form?
A. Mold phase
B. Yeast phase
C. Encapsulated
D. Latent
A
B
22
Q
The mycelial form of which dimorphic mold produces thick-walled, rectangular, or
barrel-shaped alternate arthroconidia?
A. Coccidioides immitis
B. Sporothrix schenckii
C. Histoplasma capsulatum
D. Blastomyces dermatitidis
A
A
23
Q
The yeast form of which dimorphic fungus appears
as oval or elongated cigar shapes?
A. Coccidioides immitis
B. Sporothrix schenckii
C. Histoplasma capsulatum
D. Blastomyces dermatitidis
A
B
24
Q
The mycelial form of Histoplasma capsulatum seen on agar resembles:
A. Sepedonium spp.
B. Penicillium spp.
C. Sporothrix spp.
D. Coccidioides spp.
A
A
25
The yeast form of which dimorphic mold shows a
large parent yeast cell surrounded by smaller
budding yeast cells?
A. Paracoccidioides brasiliensis
B. Sporothrix schenckii
C. Coccidioides immitis
D. Histoplasma capsulatum
A
26
Which group of molds can be ruled out when septate hyphae are observed in a culture?
A. Dematiaceous
B. Zygomycetes
C. Dermatophytes
D. Dimorphic molds
B
27
Tinea versicolor is a skin infection caused by:
A. Malassezia furfur
B. Trichophyton rubrum
C. Trichophyton schoenleinii
D. Microsporum gypseum
A.
28
Which of the following structures is invaded by the genus Trichophyton?
A. Hair
B. Nails
C. Skin
D. All of these options
D
29
An organism cultured from the skin produces colonies displaying a cherry-red color on
Sabouraud dextrose agar after 3–4 weeks and teardrop-shaped microconidia along the sides of the hyphae. The most likely identification is:
A. Trichophyton rubrum
B. Trichophyton tonsurans
C. Trichophyton schoenleinii
D. Trichophyton violaceum
A
30
Which Microsporum species causes an epidemic form of tinea capitis in children?
A. Microsporum canis
B. Microsporum audouinii
C. Microsporum gypseum
D. All of these options
B
31
Microscopic examination of a fungus cultured from a patient with athlete’s foot showed large, smooth-walled, club-shaped macroconidia appearing singly or in clusters of two to three from the tips of short conidiophores. The colonies did not produce microconidia. What is the most likely identification?
A. Trichophyton spp.
B. Alternaria spp.
C. Epidermophyton spp.
D. Microsporum spp.
C
32
Which Trichophyton species causes the favus type of tinea capitis seen in the Scandinavian countries and in the Appalachian region of the United States?
A. T. verrucosum
B. T. violaceum
C. T. tonsurans
D. T. schoenleinii
D
33
The Hair Baiting Test is used to differentiate which two species of Trichophyton that produce
red colonies on Sabouraud agar plates?
A. T. mentagrophytes and T. rubrum
B. T. tonsurans and T. schoenleinii
C. T. tonsurans and T. violaceum
D. T. verrucosum and T. rubrum
A
34
A mold that produces colonies with a dark brown, green-black, or black appearance of both the surface and reverse side is classified as a:
A. Dematiaceous mold
B. Dermatophyte
C. Hyaline mold
D. Dimorphic fungus
A
35
A rapidly growing hyaline mold began as a white colony but soon developed a black “pepper” effect on the agar surface. The older colony produced a black matte, making it resemble a dematiaceous mold. What is the most likely identification?
A. Penicillium notatum
B. Aspergillus niger
C. Paecilomyces spp.
D. Scopulariopsis spp.
B
36
Which dematiaceous mold forms flask-shaped
phialides, each with a flask-shaped collarette?
A. Phialophora spp.
B. Exophiala spp.
C. Wangiella spp.
D. All of these options
A
37
Which Aspergillus species, recovered from sputum or bronchial mucus, is the most common cause of pulmonary aspergillosis?
A. A. niger
B. A. flavus
C. A. fumigatus
D. All of these options
C
38
A hyaline mold recovered from a patient with AIDS produced rose-colored colonies with
lavender centers on Sabouraud dextrose agar. Microscopic examination showed multiseptate macroconidia appearing as sickles or canoes.
What is the most likely identification?
A. Fusarium spp.
B. Wangiella spp.
C. Exophiala spp.
D. Phialophora spp.
A
39
Material from a fungus-ball infection produced
colonies with a green surface on Sabouraud agar in
5 days at 30°C. Microscopic examination showed
club-shaped vesicles with sporulation only from
the top half of the vesicle. This hyaline mold is most probably which Aspergillus spp.?
A. A. niger
B. A. fumigatus
C. A. flavus
D. A. terreus
B
40
A rapidly growing nonseptate mold produced colonies with a gray surface resembling cotton
candy that covered the entire plate. Microscopic examination revealed sporangiophores arising between, not opposite, the rhizoids and producing
pear-shaped sporangia. What is the most likely identification?
A. Absidia spp.
B. Penicillium spp.
C. Rhizopus spp.
D. Aspergillus spp
A
41
An India ink test was performed on CSF from an HIV-infected male patient. Many encapsulated yeast cells were seen in the centrifuged sample.
Further testing revealed a positive urease test and
growth of brown colonies on niger-seed agar. The diagnosis of meningitis was caused by which yeast?
A. Candida albicans
B. Cryptococcus neoformans
C. Cryptococcus laurentii
D. Candida tropicalis
B
42
A bone marrow sample obtained from an
immunocompromised patient revealed small intracellular cells using a Wright’s stain preparation. Growth on Sabouraud–dextrose agar plates of a mold phase at 25°C and a yeast phase at 37°C designates the organism as
dimorphic. The mold phase produced thick, spherical tuberculated macroconidia. What is the most likely identification?
A. Histoplasma capsulatum
B. Sepedonium spp.
C. Sporothrix schenckii
D. Coccidioides immitis
A
43
A lung biopsy obtained from an
immunocompromised patient showed many “cup-shaped” cysts (gray to black) in a foamy
exudate (green background) using Gomori methenamine silver (GMS) stain. The organism cannot be cultured because it does not grow on
routine culture media for molds. The patient was diagnosed with pneumonia that resisted antibiotic treatment. The most likely identification is?
A. Pneumocystis jirovecci (carinii)
B. Histoplasma capsulatum
C. Sporothrix schenckii
D. Scopulariopsis spp.
A
44
Upon direct examination of a sputum specimen, several spherules were noted that contained endospores. Growth on Sabouraud–dextrose agar
showed aerial mycelial elements. The septate
hyphae produced barrel shaped arthroconidia. What is the most likely identification?
A. Penicillium marneffei
B. Scopulariopsis spp.
C. Cryptococcus neoformans
D. Coccidioides immitis
D
45
A bone marrow specimen was obtained from an immunocompromised patient who tested positive for HIV. The organism grew rapidly at 3 days
showing a mold form (at 25°C), displaying conidiophores with four to five terminal metulae
with each having four to six phialides. The conidia at the end of the phialides were oval and in short chains. They appear as a fan or broom when
viewing under 10× and 40×. At 37°C, the yeast form grew more slowly, showing conidia that
formed hyphal elements breaking at the septa to
produce oval arthroconidia. This thermodimorphic mold is most likely:
A. Paecilomyces spp.
B. Penicillium marneffei
C. Rhizomucor spp.
D. Aspergillus fumigatus
B
46
What is the specimen of choice for the initial diagnosis of Pneumocystis jirovecii (carinii) in an immunocompromised patient, such as someone
with AIDS?
A. Induced sputum
B. Open-thorax lung biopsy
C. CSF
D. Urine
A
47
A transplant patient is suspected of having
invasive aspergillosis on the basis of clinical and
radiological findings. Which specimen is best for the initial identification of aspergillosis by soluble antigen testing?
A. Blood culture
B. Lung biopsy
C. Serum or urine
D. Sputum
C
48
What is the most common cause of mucormycosis infection in humans?
A. Penicillium spp.
B. Candida albicans
C. Scopulariopsis spp.
D. Rhizopus spp.
D
49
A thermally dimorphic fungus shows a filamentous mold form with tuberculate macroconidia at room temperature, and a yeast form above 35°C. Which organism best fits this description?
A. Histoplasma capsulatum
B. Paracoccidioides brasiliensis
C. Candida albicans
D. Coccidioides immiti
A
50
SITUATION: After a vacation to the Southwestern United States, a midwesterner complained of flulike symptoms with fever, chills, nonproductive
cough, and chest pain. Microscopic exam of sputum, cleared with KOH, revealed large, thick-walled spherules containing endospores.
Upon culture, the mold phase showed septate hyphae and alternating barrel-shaped arthroconidia. Which organism is most likely the cause of this
pneumonia?
A. Coccidioides immitis
B. Histoplasma capsulatum
C. Paracoccidioides brasiliensis
D. Penicillium marneffei
A
51
Describe the types of hyphae:
Septate hyphae – presence of cross walls
Aseptate – no cross wall
Hyaline – transparent hyphae
Dematiaceous – pigmented hyphae
52
Describe the different types of chlamydoconidia:
Terminal arrangement – spores at the tip of hyphae
Sessile arrangement – spores at the side of the hypha
Intercalary arrangement – spore within the hyphal strand
53
this represents the initial stage of true hyphae formation.
Germ tube
54
SDA Inhibitor for bacteria:
Acidic pH of 5.6 in a medium
55
What’s the content of Mycosel or Mycobiotic medium and gives the function of these agents?
Chloramphenicol – inhibits bacterial growth
Cycloheximide – Inhibits saprophytic fungal growth
56
What is the indicator of Dermatophyte Test Medium (DTM)?
Phenol red
57
This is for the stimulation of conidiation and chlamydospore production in Candida species.
Also for the demonstration of blastoconidia, pseudohyphae, and arthroconidia which is used in the identification of Candida
Purpose of Cornmeal with Tween 80 agar
58
Purpose of Czapek’s Agar
This is for the detection and isolation of Aspergillus
59
This is for the isolation of Cryptococcus neoformans
Birdseed (Niger seed agar)
60
This is for the conversion of mold phase of Blastomyces dermatitidis to its yeast phase.
Cottonseed Agar
61
This is for the isolation and detection of Nocardia
Casein medium
62
This is for the differentiation between M. canis and M. audouinii where M.canis is positive while M. audouinii is negative
Rice medium
63
this is used to demonstrate germ tube production by the yeast Candida albicans.
Germ tube media
64
is to demonstrate urease production. A positive test is a development of pinkish purple within 48 hours after inoculation
Urea Agar Slant
65
Urease Positive
includes the Trichosporon, Rhodotorula, and Cryptococcus
66
Urease Negative –
includes the Geotrichum, Saccharomyces, and most Candida
67
this are used for despeciation of Trichopyhton species.
Trichophyton test agar
68
this is used primarily to recover pathogenic fungi and exclusives for dermatophytes.
Inhibitory Mold Agar
69
is a medium used to enhance sporulation and pigmentation. Also used as subculture medium rather than a primary plating medium.
Potato Dextrose Agar (PDA)
70
this is reserve for skin, hair, and nail specimen. To allow growth of fungi from these type of specimen.
SDA-CC
71
support the growth of dermatophyte isolated from skin, hair, and nail specimens.
BHI-CC & with blood
72
allows fungal contaminants and pathogenic fungi to grow. However, Histoplasma capsulatum and some strains of Nocardia asteroides failed to grow in this medium.
Using the SDA culture media
73
1. For each of the following dimorphic fungi, describe the characteristic
microscopic appearance when grown at 22 or 35°C:
a. Blastomyces dermatitidis
b. Coccidioides immitis and C. posadasii
c. Histoplasma capsulatum
d. Sporothrix schenckii species complex
2. Describe the microscopic morphology for each of the following
organisms:
a. Microsporum gypseum
b. Microsporum canis
c. Trichophyton rubrum
d. Trichophyton mentagrophytes
3. Compare the results of the urease test and the hair perforation
test for T. rubrum and T. mentagrophytes.
4. Describe the significance of isolating a saprobe from an infection
in an immunocompromised patient.
5. Compare the macroscopic and microscopic morphology of the
following saprobes: Penicillium spp., Aspergillus fumigatus, Fusarium
spp., and Curvularia spp.
6. Describe the differences between chromoblastomycosis and
eumycotic mycetoma.
7. Discuss the differences between bacteria and fungi.
8. Discuss the differences between hyaline and phaeoid fungi.
9. Define teleomorph, anamorph, and synanamorph.
10. You suspect that a yeast isolated from the oral cavity of a patient
with HIV infection is C. albicans. Describe the results of the germ
tube test. What morphology would you see if you inoculated the
colony onto cornmeal agar?
Yeasts typically reproduce by budding, whereas molds often reproduce by forming spores
74
Dermatophytoses are caused by _______, and
| ________species
Trichophyton, Microsporum, Epidermophyton
75
The thermally dimorphic fungi: Blastomyces dermatitidis, Coccidioides immitis, Coccidioides posadasii, Histoplasma capsulatum, Paracoccidioides brasiliensis, Sporothrix schenckii species complex, and
Talaromyces (Penicillium) marneffei are often associated with _______.
systemic mycoses
76
Clinically important Mucorales include:
Rhizopus, Mucor, Lichtheimia,
| Cunninghamella, and Syncephalastrum.
77
Because of its microscopic morphology, _______is a mold that
is often initially mistaken for a yeast.
Geotrichum
78
_____ are most problematic in the immunocompromised
| host.
Saprobic fungi
79
______ is the most commonly isolated yeast.
Candida albicans
80
__________is an important pathogen of patients with
| AIDS.
Pneumocystis jirovecii
81
The teleomorph or sexual form of B. dermaititdis is named ___
Ajellomyces dermatitids
82
______ is also known as Valley Fever or Desert Fever or San Joaquin Valley fever.
Coccidioides
83
________ is the biohazard of fungi to the laboratory personnel.
Coccidioides immitis
84
Ang ________ ra ang dimorphic na fungi sa subcutaneous while the rest dili man dimorphic
sporotrichosis
85
The ________, this medium is used to differentiate the T. rubrum from the T. mentagrophyte.
corn meal agar with 1% glucose
86
Cotton seed medium is for the isolation of _________
Blastomycis dermatitidis
87
Another test to differentiate systemic fungi is the performance of ______. Considered as serologic confirmation for systemic fungi.
exoantigen test
88
For blastomycis dermatitidis, for the exoantigen test, this is positive for _______, mao ni siya ang result of exoantigen test, mao ni ang ma detect.
While Histoplasma capsulatum, for the exoantigen, _______ are determined.
specific A band
| H and M bands
89
__________and _______ lang ang itest sa exoantigen test.
Blastomycis dermatitidis
| Histoplasma capsulatum
90
______ is for Aspergillus, serum at 37°C, a germ tube test wherein the serum is subjected to 37°C incubation
Czapek’s medium
91
Media with olive oil is used for the detection or isolation of _______
Malassezia furfur
92
Hair bating test positive for _________
mentagrophytes
93
Characteristic red color tear drop conidia for ________
Trichophyton rubrum.
94
Favic chandelier or antler is for the ______
Trichophyton schoeleinii
95
_________ is the most common direct microscopic examination and its purpose ii it acts a clearing agent because it digests the keratin.
10% potassium hydroxide
96
The LPCB, the common fungal stain, lactophenol cotton blue
97
__________ specifically used for the identification of Histoplasma capsulatum
Wright’s stain or Giemsa stain
98
Darling’s disease is ______ or reticuloid epithelial system parasite or also known as the Cave disease/Spelunkers disease
Histoplasma capsulatum
99
The laboratory diagnostic method to identify the Blastomycis, Paracoccidioides, Coccidioides are the _________
KOH
PAS or periodic acid Schiff,
H and E stain or haematoxylin and eosin.
100
________ is keloid-like subcutaneous nodule
Loboa loboi
101
_______aside from being known of causing South American blastomycosis, this is also known as the Lutz splendor-almeida disease. This being systemic, this affects or disseminate anhi ang infection in the spleen, liver, lymph node, and skin
Paracoccidioides brasiliensis
102
Known as Gilchrist disease or Chicago disease is ________
Blastomycosis dermatitidis
103
For exoantigen immunodiffusion tests specific bands _____suggestive of Coccidioides immitis
Then ________ is for Paracoccidioides brasiliensis.
HS, HL, and F,
| 1, 2, and 3 antigens
104
During the manipulation or identification or in culturing, the inhalation of spore or the mold phase is considered the _____. This one is not cultured so para ma identify, the diagnostic stage is the yeast found in the tissue, this one can be cultured. Ang spore cannot be cultured.
infective stage
105
In culturing, before reporting as negative for this systemic mycoses, kinahanglan ani ang _________ as negative.
4 weeks before reporting
