Mycology Lecture 4 Flashcards
(107 cards)
1
Q
opportunistic mycoses have a ____ incidence in vulnerable patient populations.
A
high
2
Q
T or F: Opportunistic mycoses are found globally.
A
true
3
Q
risk of disease by opportunistic mycoses depends on two things - what are they?
A
- host immune defects
2. facilitating conditions
4
Q
mortality rate with opportunistic mycoses is highly ______.
A
variable
5
Q
since people who get infected with opportunistic mycoses often have an immune defect, then what is important in treatment?
A
return of the immune system
6
Q
name some examples of facilitating conditions (3)
A
- indwelling vascular catheters
- surgical procedures
- trauma to skin/mucosa
7
Q
name some examples of things (like diseases or drugs) that lead to impaired immune defenses
A
- neutropenia
- impaired T cell function
- HIV/AIDS
- primary immunodeficiencies (chronic granulomatous disease)
- corticosteroids
- TNF blockers
- alcoholism
- diabetes
- pregnancy
- prematurity
8
Q
name some examples of things that lead to impaired homeostasis
A
- damage to mechanical barriers like the mucociliary escalator
- iron overload states (allows for fungi to grow)
9
Q
why is diabetes a risk factor for getting opportunistic fungal infections?
A
in patients w/ diabetes, glucose levels are increased and this allows fungi to feed
10
Q
neutropenia typically occurs following a ____ _____ or ____ ______ transplant, or intensive ____________.
A
bone marrow OR stem cell,
chemotherapy
11
Q
is candida an ascomycete or basidiomycete?
A
ascomycete
12
Q
t or f: candida is part of the normal human flora, specifically in the skin and gut
A
true
13
Q
candida is found everywhere, including in _____, _______, and _______.
A
soil, water, plants
14
Q
what is the most common fungal opportunist?
A
candida
15
Q
which fungi is a common cause of bloodstream infection in the US?
A
candida (4th most common)
16
Q
is candida able to grow on catheters, foreign bodies, and artificial heart valves?
A
yes
17
Q
more than ___ species of candida are thought to cause human disease
A
20
18
Q
which species of candida is the most common cause of systemic candidiasis?
A
c. albicans
19
Q
c. albicans is _______ to fluconazole
A
sensitive
20
Q
c. glabrata has _______ _______ to fluconazole
A
inducible resistance (via efflux pump)
21
Q
c. krusei is ________ _______ to fluconazole
A
intrinsically resistant
22
Q
c. parapsilopsis is _______ to fluconazole
A
sensitive
23
Q
this species of candida is not as frequent as other candida species, but we are seeing an increase in cases.
A
c. tropicalis
24
Q
what species of candida is labeled as emerging?
A
c. auris
25
why is c. auris concerning? (2 reasons)
- it has a difficult resistance pattern
| - it has a higher morbidity/mortality rate
26
looking at local epidemiology of candida, c. ______ is the most common, followed by c. _________
albicans, glabrata
27
name a difference in structure between pseudohyphae and hyphae
pseudohyphae is pinched and balloons outward. the true hyphae is not pinched and has parallel sides of consistent diameter.
28
c. albicans can form a ____ _____, but other species most form ________.
true hyphae, pseudohyphae
29
name 3 virulence attributes that candida has
1. adhesins
2. biofilm production
3. morphogenesis
30
an increase in ______, _____, or ______ can lead to increase in candida on your body.
warmth, moisture, nutrients
31
people with an imbalanced flora include (4)
- infants
- people who take antibiotics
- pregnant women
- diabetic patients
32
people with epithelial damage include those who have....(5 things)
- trauma
- friction
- maceration
- burns
- cancer/chemotherapy (other infections)
33
_______ damage and an ______ in candida on your body leads to ________ candidiasis
epithelial, increase, superficial
34
where candida becomes systemic, it has a high affinity for the _____ and ___, but it can also travel to the _____/_____, _____, and _____
blood, eyes, liver/spleen, brain, heart
35
_______ is very rare with candida. it does not end up in the ______ or _______ tract
pneumonia, lung, urinary tract
36
candida is associated with superficial/mucocutaneous infections, such as _______, _______, __________, and ________.
onychomycosis, vulvovaginitis, oropharyngeal, esophageal
37
the major portal of infection with candida is the ______ tract and ______.
GI tract, catheters
38
what is the most common species of candida involved in causing oropharyngeal candidiasis (thrush)?
c. albicans
39
describe the appearance of oropharyngeal candidiasis
white psuedomembranous plaque, red inflamed lesions
40
thrush is usually diagnosed based on _____, but a ____ test can be conducted as well
appearance, KOH
41
what are the risks for getting thrush? (3)
- AIDS
- antibiotic use
- steroid inhalers
42
what is the treatment for thrush?
mouthwash/lozenges (first line) or fluconazole
43
similar to thrush, c. _____ is the most common cause of esophageal candidiasis
albicans
44
candida can become present in the esophagus when it goes beyond the mouth. it is ____ to treat and is linked to ___ and difficulty _______.
harder, pain, swallowing
45
esophageal candidiasis is typically seen in ____ and ______ patients.
AIDS, cancer
46
what is the treatment for esophageal candidiasis?
fluconazole, echinocandin if resistant species
47
certain occupations are at more risk for getting onychomycosis. what occupations are those? (3)
dishwashers, bartenders, fruit pickers
48
candida is isolated from the genital tract of __ - ___ % of asymptomatic women
20-50%
49
culture for candida vulvovaginitis is not _____ because many people are ______.
specific, colonized
50
name risk factors for candida vulvovaginitis
- diabetes
- corticosteroids
- antibiotics
- pregnancy
- AIDS
- oral contraceptive
51
what is the predominant species that leads to vulvovaginal candidiasis?
c. albicans
52
what encourages growth of candida in the vagina? (3)
- estrogen therapy (high levels increase vaginal glycogen content which is a carbon source for candida)
- pregnancy
- antibiotic use (vaginal bacteria decrease, fungi can flourish)
53
how is vulvovaginal candidiasis diagnosed?
- appearance
| - lab confirmation using KOH test
54
what is the treatment for VVC?
- azoles and polyenes
| - fluconazole for 1-2 doses
55
______ colonization of candida with superficial breakdown or massive trauma/deep burns as well as _______ defenses can lead to ______ candidiasis
high, immune, systemic
56
what is candida fungemia?
blood infection where candida has invaded the blood
57
what is the mortality rate for candida fungemia?
30-40%
58
how is candida fungemia diagnosed? (4)
- blood culture
- skin biopsy
- tissue biopsy
- blood antigen test (B-D glucan)
59
what examination should patients with candida fungemia get?
eye examination
60
t or f: when a patient has candida fungemia, their heart valves is commonly infected.
false - this is rare
61
how long does candida typically take to grow? how many days to identify?
1-3 days to grow
| 1-2 days for ID
62
what is a faster method to identify candida?
MALDI-TOF and PNA-FISH
63
name non-culture methods for diagnosing candida (4)
1. antigen assays (B-D-glucan)
2. PCR (increasingly being used)
3. T2Candida (3-5 hrs from blood specimen)
4. serology (not useful)
64
candida can also be diagnosed using a ___ test. it appears as a gram ______
KOH, positive
65
looking at candida on plates, what does c. albicans look like?
whitish colored colonies with feet
66
what is CHROMagar candida?
it is a differential culture medium that identifies species of candida based on change in their color
67
the _____ _____ test is a screening procedure which is used for the ID and differentiation of c. albicans from other yeasts
germ tube
68
t of r: beta-d-glucan is unique and specific to c. albicans
FALSE - it is a cell wall component in many fungi
69
what is the sensitivity of the beta-d-glucan test for c. albicans?
80-90%
70
the beta-d-glucan test typically comes out negative for ______ and ______
cocci & mucormycosis
71
describe how t2 candida works
1. breaks up the yeast
2. amplifies the DNA
3. detects yeast DNA by using magnetic resonance technology
72
how specific is t2 candida?
99% specific
73
since there is variable levels of resistance depending on the candida species, it has been recommended to start with _______
echinocandins
74
t or f: c. auris is typically misidentified
true
75
c. auris is ___ resistant to fluconazole, and __ resistant to amp B
90%, 30%
76
c. auris can persist on _____ for _____. it is associated with outbreaks in ________ facilities.
surfaces, weeks, healthcare
77
t or f: patients with c. auris do not have to placed into contact rooms because it can't spread person to person
false
78
what is unique about the appearance of cryptococcus?
thick capsule
79
unlike candida, cryptococcus infection occurs via ______
inhalation
80
cryptococcus neoformans is an ______ pathogen, while cryptococcus gattii is a ______ pathogen
opportunistic, primary
81
what is cryptococcus gattii associated with? where is it found?
eucalyptus tree and koala bears, found in Australia, NZ, and Eastern Vancouver island
82
is cryptococcus an ascomycete or basidiomycete?
basidiomycete
83
is cryptococcus intracellular or extracellular?
extracellular
84
what are the two mating types of cryptococcus?
a and alpha
85
which one is more virulent: a or alpha?
alpha - also more common in clinical infections
86
what are the 3 main virulence attributes of crypto?
1. polysaccharide capsule
2. melanin production
3. mating type (a or alpha)
87
C. neoformans is _____ encapsulated in the environment. it is _____ in size, which allows it to sneak into the alveoli of our lungs.
weakly, small
88
C. neoformans becomes _______ in the lungs, where the capsule becomes ______
rehydrated, thicker
89
the thick capsule that crypto has once in the lungs is beneficial because .....
it allows it to hide from our immune system (protects phagocytosis, barrier for complement)
90
if crypto has a mutation that renders its capsule biosynthesis pathway defective, then it becomes ______
avirulent
91
how does high salt affect capsule size? low glucose? low iron? physiological CO2?
decreases, increases, increases, increases
92
what is the function of melanin?
protects fungal cells from respiratory burst
93
t or f: crypto mutants that cannot produce melanin are completely avirulent
false - it's reduced
94
localized pulmonary crypto is usually ________ and can be left untreated (c. _____)
self-limiting, c. neoformans
95
invasive pulmonary crypto can lead to _________, and it is rare except in patients who are _________
dissemination, immunocompromised
96
crypto meningitis is characterized by increased _________ _____
intracranial pressure
97
what treatment is used for crypto meningitis?
lumbar puncture, or surgical drain to remove CSF
98
what is treatment for crypto meningitis?
amp B and 5FC then fluconazole
99
in an unhealthy host, what antifungal should be used for crypto pneumonia? what about for a normal host?
fluconazole, in normal host no treatment required
100
what is the biggest risk factor for c. neoformans meningitis?
AIDS (15% of AIDS related deaths globally)
101
where are most cases of c. neoformans localized?
sub-saharan africa
102
for crypto meningitis in resource limiting countries, there is a ___ morality rate if getting HIV care, but ____ if not
70%, 100%
103
for crypto meningitis in north america, there is a ___ morality rate if getting HIV case, but ___ if not
20%, 30%
104
how is crypto diagnosed? (4)
- crypto antigen (CrAg): using serum (ie blood) or CSF
- culture
- histology (capsule stains red with mucicarmine stain, black with silver stain)
- PCR
105
how is c. neoformans told apart from c. gattii?
PCR
106
what does crypto look like?
narrow based budding yeast
107
what diagnostic test is done for crypto out of historical interest?
india ink prep CSF (capsule excludes ink)
