Diagnostic Mycology PART 1

Question 1

Characteristic Features of Fungi Seen in Direct Examination of Clinical Specimens: Morphologic Form Found in Specimens

Answer 1

1. Yeastlike
2. Spherules
3. Yeast and pseudohyphae or hyphae
4. Pauciseptate hyphae
5. Hyaline septate hyphae
6. Dematiaceous septate hyphae
7. Sclerotic bodies
8. Granules

Question 2

Yeastlike fungi:

Answer 2

1.Histoplasma capsulatum (2-5)
2.Sporothrix spp. (2-6)
3.Cryptococcus spp. (2-15)
4.Malassezia furfur (infungemia) (1.5-4.5 )
5.Blastomyces spp. (8-15)
6.Paracoccidioides brasiliensis (5-60)

Question 3

Small; oval to round budding cells;
often found CLUSTERED IN HISTIOCYTES;
difficult to detect when present in small
numbers

Answer 3

Histoplasma capsulatum

Question 4

Small; oval to round to CIGAR SHAPED
single or multiple buds present;
uncommonly seen in clinical specimens

Answer 4

Sporothrix spp.

Question 5

Cells exhibit great variation in size;
usually spherical but may be FOOTBALL SHAPED ; buds single or multiple and “pinched off”; capsule may or may not be evident;
occasionally, pseudohyphal forms with or
without a capsule may be seen in
exudates of cerebrospinal fluid

Answer 5

Cryptococcus spp.

Question 6

Small; BOTTLE SHAPED cells, buds separated
from parent cell by a septum;
emerge from a small collar.

Answer 6

Malassezia furfur (in fungemia)

Question 7

Cells are usually large, DOUBLE REFRACTILE
when present; buds usually single;
however, several may remain attached to
parent cells; buds connected by a BROAD BASE

Answer 7

Blastomyces spp.

Question 8

Cells are usually large and are surrounded
by smaller buds around the periphery
(“mariner’s wheel appearance”); smaller
cells may be present (2-5 µm) and
resemble H. capsulatum; buds have
“pinched-off” appearance

Answer 8

Paracoccidioides brasiliensis

Question 9

Spherules Fungi:

Answer 9

1. Coccidioides spp. 10-100
2. Rhinosporidium seeberi 6-300 (protozoan pathogen that is studied in
   mycology)

Question 10

Vary in size; some may contain
endospores, others may be empty;
adjacent ____may resemble
Blastomyces spp.; endospores may
resemble H. capsulatum but show no
evidence of budding; may
produce multiple germ tubes if a direct
preparation is kept in a moist chamber
greater than/equal to 24 hr

Answer 10

Coccidioides spp.

Question 11

Large, thick-walled sporangia containing
sporangiospores are present;
mature sporangia are LARGER THAN
spherules of Coccidioides;
hyphae may be found in cavitary lesions.

Answer 11

Rhinosporidium seeberi

Question 12

Yeast and pseudohyphae or hyphae fungi:

Answer 12

1. Candida spp. except Candida glabrata 5-10
2. M. furfur (in tinea versicolor) 3-8 (yeast)
   2.5-4 (hyphae)

Question 13

Cells usually exhibit single budding;
pseudohyphae, when present, are
constricted at the ends and remain
attached like links of sausage; hyphae,
when present, are septate.

Answer 13

Candida spp. except Candida glabrata

Question 14

Short, curved hyphal elements are usually
present, along with round yeast cells that
retain their spherical shape in compacted
clusters; “spaghetti and meatballs.

Answer 14

M. furfur (in tinea versicolor)

Question 15

Pauciseptate hyphae Fungi:

Answer 15

Mucorales: Mucor,Rhizopus, and other
genera 10-30

Question 16

Hyphae are large, ribbonlike, often
fractured or twisted; occasional septa may
be present; smaller hyphae are confused with those of Aspergillus spp., particularly Aspergillus flavus

Answer 16

Mucorales: Mucor, Rhizopus, and other
genera

Question 17

Hyaline septate hyphae Fungi:

Answer 17

1. Dermatophytes, skin and nails 3-15
2. Dermatophytes, hair 3-15
3. Aspergillus spp 3-12
4. Geotrichum spp. 4-12
5. Trichosporon spp. 1-4 by 8

Question 18

Hyaline, septate hyphae are commonly
seen; chains of arthroconidia may be present.

Answer 18

Dermatophytes, skin and nails

Question 19

Arthroconidia on periphery of hair shaft
producing a sheath indicate ectothrix
infection; arthroconidia formed by
fragmentation of hyphae in the hair shaft
indicate endothrix infection.
Long hyphal filaments or channels in the
hair shaft indicate favus hair infection

Answer 19

Dermatophytes, hair

Question 20

Hyphae are septate and exhibit
dichotomous, 45-degree branching; larger
hyphae, often disturbed, may resemble
those of Mucorales

Answer 20

Aspergillus spp.

Question 21

Hyphae and rectangular arthroconidia are
present and sometimes rounded; irregular
forms may be present.

Answer 21

Geotrichum spp.

Question 22

Hyphae and rectangular arthroconidia are
present and sometimes rounded;
occasionally, blastoconidia may be
present.

Answer 22

Trichosporon spp.

Question 23

Dematiaceous septate hyphae fungi:

Answer 23

1.Bipolaris spp.,
2.Cladosporium spp.,
3.Curvularia spp.,
4.Exophiala spp.,
5.Exserohilum spp.,
6.Hortaea werneckii,
7.Phialophora spp

Question 24

Dematiaceous polymorphous hyphae are
seen; budding cells with single septa and
chains of swollen rounded cells are often
present; occasionally, aggregates may be
present in infection caused by

Answer 24

BEECCH Phia 2-6

1.Bipolaris spp.,
2.Cladosporium spp.,
3.Curvularia spp.,
4.Exophiala spp.,
5.Exserohilum spp.,
6.Hortaea werneckii,
7.Phialophora spp

Question 25

Sclerotic bodies Fungi:

Answer 25

1.Cladosporium carrionii
2.Fonsecaea compacta
3.Fonsecaea pedrosoi
4.Phialophora verrucosa
5.Rhinocladiella aquaspersa

Question 26

White, soft granules without a
cementlike matrix. 200-300

Answer 26

Acremonium
2.Acremonium falciforme
3.Acremonium kiliense
4.Acremonium recifei

Question 27

Brown, round to pleomorphic,
thick-walled cells with transverse
septations; commonly, cells contain two
fission planes that form a tetrad of cells

Answer 27

sclerotic bodies
(5-20)
1.Cladosporium carrionii
2.Fonsecaea compacta
3.Fonsecaea pedrosoi
4.Phialophora verrucosa
5.Rhinocladiella aquaspersa

Question 28

Black, hard grains with a cementlike
matrix at the periphery

Answer 28

Aspergillus 500-1000
-Aspergillus nidulans

Question 29

White, soft granule without a cementlike
matrix. 65-160 dm/mm

Answer 29

Curvularia
-Curvularia geniculata
-Curvularia lunata

Question 30

Black, soft granules, vacuolated,
without a cementlike matrix, made of
dark hyphae and swollen cells.

Answer 30

Exophiala 200-300
-Exophiala jeanselmei

Question 31

White, soft granules without a
cementlike matrix 200-500

Answer 31

Fusarium
-Fusarium moniliforme

Question 32

300-600 size range granule

Answer 32

Fusarium solani

Question 33

Black, soft granules without a
cementlike matrix; the periphery is
composed of polygonal swollen cells
and the center has a hyphal network

Answer 33

Madurella 350-500
-Madurella grisea

Question 34

Black to brown, hard granules;
two types:
(1) rust-brown, compact, filled with
cement-like matrix;
(2) deep brown, filled with numerous
vesicles, 6-14 µm in diameter,
cementlike matrix in periphery, central
area of light-colored hyphae.

Answer 34

Madurella mycetomatis 200-900

Question 35

White, soft granules with cementlike
matrix at the periphery. 300-600

Answer 35

Neotestudina
-Neotestudina rosatii

Question 36

White, soft granules composed of
hyphae and swollen cells at the
periphery in a cementlike matrix.

Answer 36

Pseudallescheria 200-300
-Pseudallescheria boydii