U6 LEC: OPPORTUNISTIC MYCOSES Flashcards
(137 cards)
1
Q
Infections in patients with immune deficiencies who would otherwise not be infected.
A
Opportunistic Mycoses
2
Q
Opportunistic mycoses are seen in those people with impaired host defenses such as?
A
- AIDS
- Alteration of Normal Flora
- Diabetes Mellitus
- Immunosuppressive therapy
- Malignancy
3
Q
Part of a normal human flora
A
Endogenous
4
Q
Examples of Endogenous Mycoses
A
- Candida spp.
- Pneumocystis jirovecii
5
Q
Most common endogenous mycoses, indicator of weak immune system
A
thrush (Candida spp.)
6
Q
Fungus does not normally live in/on human body
A
Exogenous
7
Q
Examples of Exogenous Mycoses
A
- Cryptococcus neoformans
- Aspergillus (different species)
- Zygomycetes
- Many Other Fungi
8
Q
Causative agent of Candidiasis or Moniliasis
A
Candida albicans and other Candida spp.
9
Q
Candida albicans causes?
A
Candidiasis or Moniliasis
10
Q
Candidiasis
oval, buddying yeast that produces?
A
pseudohyphae
11
Q
T/F: Candida albicans causes the most frequent opportunistic fungal infections.
A
True
12
Q
Candidiasis
harmless inhabitants of the?
A
skin and mucous membranes (RT, GIT, Female Genital Tract)
13
Q
T/F: Normal immune system keeps Candida on body surfaces.
A
True
14
Q
Other Candida species
A
- C. tropicalis
- C. krusei
- C. parapsilosis
- C. glabrata
- C. gullermondii
- C. lusitaniae
- C. kefyr
15
Q
Candidiasis
Main Defense Mechanisms
A
- skin and mucous membranes integrity
- presence of normal bacterial flora
- phagocytosis
- killing (most in PMNs, less in macrophages)
- T cells (CD4)
16
Q
Candidiasis
Important Risk Factors
A
- Neutropenia
- Diabetes mellitus
- AIDS
- SCID
- Myeloperoxidase defects
- Broad-spectrum antibiotics
- Indwelling catheters
- Major surgery
- Organ transplantation
- Neonates
- Severity of an illness
- Intravenous drug addicts
17
Q
Candidiasis
Clinical Forms
A
- Cutaneous and Mucosal
- Invasive
18
Q
Candidiasis
Manifestations under Cutaneous and Mucosal Candidiasis
A
- Oral thrush
- Oezophagitis
- Vulvovaginal infection
- Cutaneous candidiasis (skin trauma, burn patients)
- Onchomycosis
- Mucocutaneous candidiasis (SCID patients)
19
Q
Invasive Candidiasis also refers to?
A
Systemic, Disseminated, Hematogenous Candidiasis
20
Q
Invasive Candidiasis
begins with?
A
candidemia (only 50% can be proven)
21
Q
Invasive Candidiasis
If phagocytic system is normal?
A
invasive infection stops here (destroyed by phagocytes)
22
Q
Invasive Candidiasis
If phagocytic system is compromised?
A
infection spreads to many organs (causes focal infection)
23
Q
Invasive Candidiasis
Mortality of candidemia
A
30-40%
24
Q
Candidiasis
Specimen
A
- Swabs or scrappings from lesions
- Sputum
- CSF
- Exudates
25
Candidiasis
Microscopic
Gram (+) oval, budding yeast/elongated budding cells in chain (pseudohyphae)
26
Candidiasis
SDA
soft, cream-colored colonies with yeasty odor, surface growth consists of oval budding cells
27
Candidiasis
Ferments?
glucose and maltose producing acid and gas
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Candidiasis
Serological test
Precipitation tests
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This agar is used to differentiate Candida based on?
color
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CHROM agar
Green
C. albicans
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CHROM agar
Pink
C. krusei
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CHROM agar
Metallic blue
C. tropicalis
33
CHROM agar
White to mauve
Other species
34
This is done for Candida albicans in presence of high protein content.
Germ tube
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Germ Tube
specimen
plasma or serum
36
Germ Tube
(+) result
presence of germ tube
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Germ Tube
What Candida spp. is present if there is (+) result?
Candida dubliniensis
38
Chlamydoconidia is present in?
C. albicans and C. dubliniensis
39
Candidiasis
Epidemiology
- Endogenous
- Cross infections (ICU patients)
40
Candidiasis
Treatment
Neutropenic patients: Amphotericin B
Non neutropenic patients:
Nystatin, Caspofungin
41
Candidiasis
This treatment suppresses intestinal and vaginal candidiasis
Nystatin
42
Causative agent of Pneumocystis Pneumonia
Pneumocystis jirovecii
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Pneumocystis jirovecii causes?
Pneumocystis Pneumonia
44
Pneumocystis jirovecii is formerly called?
P. carinii
45
Pneumocystis
previously classified as?
protozoa
46
Pneumocystis
considered as fungus based on?
nucleic acid and biochemical analysis
47
Pneumocystis
Present in?
lung of many mammals
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Pneumocystis
Infection in humans
persistent but harmless
49
Pneumocystis
Main Risk Factors
- AIDS
- Transplantation
- Corticosteroid
- Antineoplastic therapy
50
Pneumocystis
Main defense mechanism
T-cell mediated
51
Pneumocystis
Causes what in immunocompromised patients?
Interstitial pneumonitis
52
Pneumocystis
Specimens can be?
sputum, bronchoalveolar lavage
53
Pneumocystis
Treatment and Prevention
Co-trimoxazole or Pentamidine
54
Causative agent of Cryptococcosis or Torulosis
Cryptococcus neoformans
55
This causes Cryptococcosis
Cryptococcus neoformans
56
Other term for Cryptococcosis
Torulosis
57
Cryptococcosis
causes an acute or chronic infection that involves the brain, called?
meningitis
58
Cryptococcosis
occurs worldwide in?
soil and in bird droppings
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Cryptococcosis
Prominent feature
thick polysaccharide capsule
60
Cryptococcosis
Infection is via?
respiratory tract
61
Cryptococcosis
Symptoms associated with?
nonspecific pulmonary signs and symptoms
62
Cryptococcosis
May disseminate in other organs like?
brain (cryptococcal meningitis)
63
Cryptococcosis
Clinical manifestation
slowly developing chronic meningitis that resembles a brain tumor, brain abscess, degenerative CNS disease
64
Cryptococcosis
Specimen
CSF, Exudate, Sputum, Urine
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Cryptococcosis
Microscopic
round or ovoid, often budding with thick capsule
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Cryptococcosis
SDA
cream, shiny, mucoid colonies
67
Cryptococcosis
Serological tests
Cryptococcal polysaccharide capsular antigen test, latex agglutination test
68
Cryptococcosis
Treatment
Combination of chemotherapy of Amphotericin B and Flucytosine
69
Cryptococcosis
Main Risk Factors
- T cell deficiency (AIDS)
- Corticosteroid therapy
- Organ transplantation
- Hematological malignancy
70
Cryptococcosis
Main Defense Mechanism
T cells
71
Cryptococcosis
Treatment
Amphotericin B +
- Flucytosine
72
Cryptococcosis
Recurrence Prevention
Fluconazole
73
Cryptococcosis
Epidemiology
Exogenous, not transmitted from human to human
74
Cryptococcosis
This agar is used to detect the enzyme, phenol oxidase
Niger Seed Agar (Bird Seed Agar)
75
Causative agent of Aspergillosis
Aspergillus spp.
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Aspergillus spp. causes?
Aspergillosis
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Aspergillosis
Worldwide occurring saprophytes, living in?
soil and plants (small conidia that form aerosols)
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Aspergillosis
Most common
Aspergillus fumigatus
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Aspergillosis
Other species
- A. flavus
- A. niger
- A. terreus
- A. nidulans
80
Aspergillosis
Produces aflatoxins in food
A. flavus
81
Aspergillosis
Specimen
Tissue biopsy
82
Aspergillosis
Microscopic
hyphal fragments (using methenamine silver)
83
Aspergillosis
Cultivation in SDA
gray to green colonies
84
Aspergillosis
Main Defense Mechanisms
Phagocytosis
85
Aspergillosis
Treatment
- Amphotericin B
- Itraconazole
- Flucytosine
- Surgery
86
Aspergillosis
Prevention
Avoid exposure to conidia (new buildings)
87
Aspergillosis
Main Risk Factors
- Hematological malignancy
- Bone marrow transplantation
- Corticosteroid therapy
88
Causative agent of Zygomycosis
- Mucor
- Rhizopus
- Absidia
- Rhizomucor
89
Zygomycosis is also called as?
Mucormycosis
Phycomycosis
90
Zygomycosis
invasive disease caused by?
Zygomycetes (Mucor, Rhizopus, Rhizomucor, Absidia)
91
Zygomycosis
These fungi are?
ubiquitous thermotolerant saprophyte
92
Zygomycosis
spores are present in?
air and dust
93
Obsolete polyphyletic taxon, forms coenocytic hyphae and reproduce asexually by producing sporangiophores within which develops sporangiospores
Class Phycomycetes
94
Rhizopus
Mycelium, 3 types of hyphae
- Stolon
- Rhizoid
- Sporangiophores
95
Mucor
Mycelium
1 type only: Sporangiophores
96
Rhizoids
R: Present
M: not present
97
Food
R: absorbed by rhizoids
M: absorbed by entire mycelial surface
98
Sporangiophores
R: occurs in tufts from the stolons opposite the rhizoids
M: occur singly from any point on the mycelium
99
Spores
R: easily disseminated by the wind
M: remain adhered to the columella, not easily disseminated
100
Absidia
Difference from Rhizopus
Rhizoids in between Sporangiosphores
101
Absidia
Difference from Mucor
Mucor have no rhizoids
102
Rhizomucor
Difference from Mucor
have rhizoids and stolons, grow at 50-55C
103
Rhizomucor
Difference from Absidia
have globose sporangia, sporangiophores are not swollen where they merge with the columella
104
Zygomycosis
Risk Factors
- Acidosis
- Leukemias
- Lymphoma
- Corticosteroid treatment
- Severe burns
- Immunodeficiencies
105
Zygomycosis
Clinical Manifestations
- Rhinocerebral Mucormycosis
- Thoracic Mucormycosis
- Other sites of invasion
106
This disease can progress rapidly with invasion of the sinuses, eyes, cranial bones and brain
Rhinocerebral Mucormycosis
107
Rhinocerebral Mucormycosis
Results from germination of?
sporangiospores in nasal passages
108
Rhinocerebral Mucormycosis
Invasion of?
hyphae into blood vessels
109
Rhinocerebral Mucormycosis
Invasion of hyphae causes?
- Thrombosis
- Infarction
- Necrosis
110
Rhinocerebral Mucormycosis
Patients develop?
- edema of involved facial area
- bloody nasal exudate
- orbital cellulitis
111
Rhinocerebral Mucormycosis
Almost invariably associated with?
- acute diabetes mellitus
- debilitating disease (leukemia, lymphoma)
112
Thoracic Mucormycosis
Follows inhalation of sporangiospores with?
invasion of lung parenchyma and vasculature
113
Thoracic Mucormycosis
In both locations, this causes massive tissue destruction
ischemic necrosis
114
Other Sites of Invasion
Skin infections following burns or surgery
Primary cutaneous infections
115
Other Sites of Invasion
These are also reported
Subcutaneous zygomycosis
116
Zygomycosis
Specimen
Nasal discharge, sputum, biopsy
117
Zygomycosis
Microsopic (KOH)
broad and aseptate, branched mycelium, sometimes distorted hyphae, clearly stained by Methenamine silver stain
118
Zygomycosis
SDA
Abundant and cottony
119
Zygomycosis
Treatment
Amphotericin B
120
Causative agent of Penicilliosis / Talaromycosis
Talaromyces marneffei
121
Talaromyces marneffei causes?
Penicilliosis
122
Other term for Penicilliosis
Talaromycosis
123
Talaromyces marneffei is formerly known as?
Penicillium
124
T/F: There are more than 100 Penicillium species.
False
more than 150
125
Penicilliosis
Form
thermally dimorphic
126
Penicilliosis
Present in?
environment (saprophytes), grow on various substrates (bread, jam, fruit, cheese)
127
Penicilliosis
Important opportunistic pathogen in?
HIV infected
128
Penicilliosis
Causes?
disseminated infection with multiple organ involvement
129
Penicilliosis
Common in?
Southeast Asia
130
Penicilliosis
Risk Factors
- Adult-onset immunodeficiency syndrome
- Cancer
- HIV/AIDS
- Organ transplant
131
Penicilliosis
These can also get Talaromycosis.
Bamboo rats (no evidence of spread from rats to people)
132
T/F: Penicilliosis has no person to person spread.
True
133
Penicilliosis
Specimen
Bone marrow, blood, lung fluids, lymph nodes, skin
134
Penicilliosis
Microscopic
yeast are small, oval, 2-4um in diameter
135
Penicilliosis
SDA
yellow green colonies with characteristic soluble red pigment
136
Penicilliosis
Molecular techniques
PCR
137
Penicilliosis
Treatment
Amphotericin B, Oral Itraconazole
