L12 Pathogensis - medically important fungi Flashcards
1
Q
what are fungi
A
eukaryotes
saprophytic or parasitic
2
Q
what makes fungi eukaroytic
A
nuclear membrane
mitosis
3
Q
what makes fungi saprophytic
A
live on dead/decaying matter
4
Q
what makes fungi parasitic
A
live on another organism at its expense
5
Q
what is the fungal cell wall include
A
firm polysaccharide structure
cell walls - cellulose and chitin
6
Q
how may fungi exist
A
single cell (yeast) connecting filaments/hyphae (filamentous fungi/moulds)
7
Q
size difference between bacteria and fungi
A
fungi 20-50um3
bacteria 1-5um3
8
Q
cytoplasm difference between bacteria and fungi
A
fungi have mitochondria, ER etc. none in bacteria
9
Q
cell wall difference in bacteria and fungi
A
fungi have chitin
bacteria have muramic acid
10
Q
dimorphism difference between bacteria and fungi
A
fungi may be present
not in bacteria
11
Q
bacteria treatment
A
penicillins
aminoglycosides
12
Q
fungi treatment
A
azoles
amphoteracin
13
Q
filamentous fungal growth characteristics
A
filamentous group grow long
14
Q
yeast fungal growth characteristic
A
budding of daughter
15
Q
what are the types of fungal reproduction
A
asexual and sexual
16
Q
what is the asexual fungal reproduction
A
spores singly or multitudes from specialised structures disseminate
17
Q
what is the sexual reproduction
A
fungi are haploid - meiosis occurs following cell fusion
18
Q
what is the anti fungal target usually
A
ergosterol
19
Q
what is a fungal marker for infection
A
beta glucan
20
Q
what are the fungal pathogen classifications
A
yeasts
yeast like fungi
filamentous fungi
dimorphic fungi
21
Q
what are yeasts
A
spherical
often budding
22
Q
example of yeast
A
cryptococcus neoformans
23
Q
what are yeast like fungi
A
elongated yeasts
pseudomycelia may be seen
24
Q
example of yeast like fungi
A
candida albicans
25
what do filamentous fungi form
form carpet or layer (mould)
26
example of filamentous fungi
aspergillus fumigatus
27
what are dimorphic fungi
may exist as yeast or filamentous fungi
28
example of dimorphic fungi
histoplasma capsulatum
29
what is important within medically important fungi
frequency
pathogenicity
therapeutics
30
what diseases does fungi cause
superficial
subcutaneous
systemic
31
examples of superficial fungal infection
hair, nails, mucous membranes
32
what causes superficial infection
changes in host resistance and normal flora, or physical contact.
e.g. AB can affect natural flora
33
examples of subcutaneous infection
skin or deeper tissues
34
what causes subcutaneous infection
often soil
35
what causes a systemic infection
inhale fungi
36
what does systemic infection cause
pneumonia or invasion of bloodstream
37
how are fungal diseases diagnosed
```
clinical suspicion
microscopy
culture
histology
AB/antigen
skin test
```
38
when is there clinical suspicion of fungal infection
fever
unresponsive to antibacterials
meningitis/pneumonia in immunocompromised
39
microscopy examples
gram stain
india ink
wet prep
40
how are superficial infections diagnosed
visual or skin scrape for microscopy
41
how are systemic infections diagnosed
blood culture
tissue (e.g.lung biopsy)
serology
antigen detection
42
what are yeast like fungi like
opportunistic pathogen
43
where are yeast like fungi present
GI and respiratory flora
44
who are predisposed to overgrowth/infection of yeast like fungi
```
diabetes mellitus
malignancy
neutropenia
defects in cell-mediated immunity
trauma
drugs e.g. antibacterials, corticosteroids, contraceptive pill
```
45
where can candida infect
```
usually thrush
eyes
spleen
liver
etc
```
46
how is dissemianted candidiasis detected
use imaging of chest but cant detect the infection but see infected
47
where do filamentous fungi infect
keratinous tissues of hair, naols, skin
48
how are filamentous fungi diagnosed
clinical
| scrapings for microscopy and culture
49
what is the treatment for filamentous fungi
clotrimazole
| terbinafine
50
what is tinea capitis
filamentous fungi infection
51
what does tinea capitis cause
head infection
hair loss
flaky skin
52
what does tinea pedis cause
atheletes foot
inflammatory reaction
swelling
53
what does tina unguium cause
chronic nail infection difficult to get rid of
54
where are aspergillus fumigatus present
ubiquitous spores
| soil dust
55
what illness does aspergillus fumingatus cause
pulmonary
systemic
other e.g. sinusitis, endocariditis
56
pulmonary effects of aspergillus fumingatus
asthma, aspergilloma (fungal ball), can be invasive
57
where can aspergillus fumingatus infect when systemic
lung
renal
cerebral
58
what is the aspergillus fumingatus treatment
iv voriconazole or Amphoteracin B (Liposomal) / po Itraconazole voriconazole
59
what is the effect of liposomal amphotericin b to normal
allow higher doses without being too toxic to kidneys
60
what fungi is aspergillus fumigatus
filamentous fungi
61
what fungi is crytococcus neoformans
true yeast
62
where is crytococcus neoformans present
environment - soil, bird poo
63
what is crytococcus neoformans
opportunistic pathogen
64
who are predisposed to crytococcus neoformans
defects in cell-mediated immunity (low CD4+ T-cells)
65
what are the clinical consequences of crytococcus neoformans
meningitis in HIV/cancer patients
pulmonary disease
disseminates quickly
pulmonary infection can be asymptomatic but spread from lungs
66
how can crytococcus neoformans be diagnosed
clinical suspicion
microscopy
culture
antigen detection
67
what are the clinical suspicions of crytococcus neoformans
signs + symptoms; e.g. meningitis in an HIV patient
68
what stain is used for crytococcus neoformans
india ink stain
69
what sample is used for crytococcus neoformans microscopy
CSF
70
what sample is used for crytococcus neoformans culture
CSF
| blood
71
what sample is used for crytococcus neoformans antigen detection
CSF
| blood
72
what is the treatment for cryptococcus neoformans
iv Amphoteracin B (Liposomal) +/- 5-flucytosine
73
why is cryptococcus neoformans difficult to eradicate
the infection can sequester in different areas of body
74
what is used to prevent cryptococcus neoformans relapse
po fluconazole maintenance
75
what can you detect c. neoformans in
CSF
| bood
76
what does a cryptococcal pulmonary infection look like on xray of chest
cant see it is cryptococcus need to grow from biopsy or sputum
77
what fungi is pneumocystis jiroveci
atypical fungus related to yeasts
78
why was pneumocystis jiroveci reclassified from a protozoan
cell wall composition; ribosomal RNA gene sequence
79
why is pneumocystis jiroveci difficult
cannot be grown in vitro
difficult to study
cant do sensitivity tests
80
why was pneumocystis jiroveci originally a protozoa
does not respond to conventional anti-fungal agents
81
what is pneumocystis jiroveci
opportunistic pathogen
82
what can pneumocystis jiroveci cause
pneumonia
83
how is pneumocystis jiroveci diagnosed
microscopy/cytology of bronchoalveolar lavage
84
what is pneumocystis jiroveci treatment
co-trimoxazole
| pentamidine
85
what does pneumocystis pneumonia look like on chest xray
black background is hazy
86
what is PCP
pneumocystis pneumonia
87
what does the histology of pneumocystis pneumonia show
foamy exudate fills alveolar spaces
88
what is pneumocystis pneumonia like - fluorescent monoclonal AB
cysts appear apple green
89
what is pneumocystis pneumonia like on silver stain
cysts are black
90
what is the pneumocystis pneumonia diagnosis
now usually by PCR on throat swabs / respiratory samples or EDTA blood
91
where is histoplasma capsulatum present
mould in environment
| yeast in tissues
92
where is histoplasma capsulatum common
eastern/central USA
93
what is the histoplasma capsulatum treatment
iv Amphoteracin B
94
what are the clinical effects of histoplasma capsulatum
asymptomatic
acute/chronic respiratory infection
disseminated disease (liver, lungs, spleen) – esp. in HIV +ve patients
95
where are histoplasma capsulatum in the body
macrophages as yeast
