Introduction to Infectious Agents 4 Flashcards
(106 cards)
1
Q
bacteria that have cell wall and can’t be used with gram pos/neg stain, what stain can be used?
A
acid-fast stain
2
Q
acid-fast will stain what color
A
pink
3
Q
non acid-fast will stain what
A
violet
4
Q
how do acid-fast stain work
A
bacteria on slide. initial stain: carbol fuchsin. if they take up the carbol fuchsin they will not be decoloriazed with decoloriser. then use counterstain.
5
Q
what bacteria is acid-fast stain used for
A
mycobacterium
6
Q
why are mycobacterium cannot do gram stain
A
high wax content in wall
7
Q
example of acid-fast bacteria:
A
Mycobacterium
8
Q
what is present in acid fast cell wall
A
Mycolic acid*
Trehalose dimycolate
Lipoarabinomannan
Arabinogalactan
9
Q
example of bacteria without cell wall
A
mycoplasma
10
Q
what do bacteria of no cell wall bacteria contain
A
sterols
11
Q
what do no cell wall bacteria use to maintain fluiditiy
A
sterols
12
Q
what is function of adhesins on cell wall less bacteria
A
adhesins - allow them to move like caterpillar
13
Q
where is site of atp production in bacteria
A
plasma/cell memrane
14
Q
what is plasma/cell membrane made out of in bacteria
A
phospholipid bilyaer
15
Q
flagella are made of what
A
flagellin proteins
16
Q
peritrichous
A
flagella all over the surface
“bad hair day”
17
Q
lophotrichous
A
a tuft of flagella at one end
18
Q
amphitrichous
A
one or more flagella at each end
19
Q
monotrichous
A
one flagellum
20
Q
where is axial filament found
A
only in perplasmic space
21
Q
pilus and fimbria are made of what
A
pilins (pilus) and fimbrins (fimbria)
22
Q
what is function of pilus and fimbria
A
adhesion to host cell surface
virulence factor
cell communication
23
Q
genetic exchange of bacteria - what is needed for this to occur
A
sex pili (F pili)
24
Q
describe structure of fimbriae on gram neg and gra positive
A
Gram +ve differs from Gram –ve fimbriae
25
capsule also called
glycocalyx and slime layer
26
what is function of capsule
anti-phagocytic (prevents phagocytocsis)
prevent dehydration
antibiotic penetration (makes it hard to treat with antibiotics)
27
capsules grow around
individual bacteria
28
what grows around colony of bacteria
biofilm
29
biofilm provides what advantage
protects against
phagocytosis
dehydration
antibiotic penetration
30
when is biofilm a huge bad thing in medical
if they grow on implanted stuff in body
31
what is genetic material in bacteria
hapoid DNA chromosome wound in nucleoid
32
pathogenicity islands
tend to find aggregation of genes that have antibiotic resistance, etc.
have G+C content
33
plasmids
extra chromosomal genetic elements
| non-essential genetic info
34
what is an example of what can be contained in a plasmid
drug resistance
35
how many copies of plasmid
one or more ( no more than 20)
36
ribosomes in bacteria
70S
| require N-formyl
37
what is significant about N-formyl on ribisomes in bacteria
chemoattractants - we have receptors that can recognize and bind to them and destroy. esp. neutrophils
38
in storage granules in bacteria what will be depsotied
glycogen
lipids
polyphosphates
39
why are storage granules used in bacteria
when ther eare unfavorable conditions
40
endospores
not reproductive - theya re just formed to allow bacteria to survive unfavorable conidions
not metabolically active
41
what does the core of endospore contain
high concentrations of calcium bound to dipicolini acid + keratin-like protein
42
draw a endospore
pg 50
43
within dehydrated core what will you find in endospores
ribosomes
44
what are 3 main wais bacteria uptake material
facilitated diffusion
active transport
group trnaslocation
45
can facilitated difussion work against concentration gradient
no
46
can active transpot and group translcoation work against concentration gradient
yes
47
group translocation
material that is translocated is modified by chemical group, usually phsphate from pyruvate. it is similar to active transport except that it is modified.
48
in gram neg. bacteria how many secretion systems are there
6
49
type III secretion apparatus in gram neg. is used to do what
used to inject toxins into host cell
50
what is type III secretion apparatus similar to in function
syringe
51
bacterial products (name 3)
exoenzymes
exotoxins
endotoxins
52
endotoxins
endotoxins not released but can be following bacterial cell damage
53
exoenzymes
degradative/hydrolytic
| ex: lipases, proteases, hyaluronidase, hemolysins, DNases
54
certain species of bacteria secrete enzyme that forms clot, and what does clot do
surrounds bacteria
55
exotoxins - three main clases
A-B toxins
membrane-disrupting toxins
superantigens
56
exotoxins
produced by gram pos and gram neg.
never secreted through type III secretion appartus
have ot bind to receptor on surface of host cell to get into cell
57
A-B toxins what are subuntis
A & B
58
b subunit does what
binds to receptor on surface of cell
59
ex of b subunit
cholera toxin
60
A subunit does what
activates adenylyl cyclase which leads to disuprtion (in cholera)
mediates enzymatic activity resopsneible for toxcitiy
61
vaccines against A-B toxins
go against B subunit to prevent it from biding, it prevents toxin activity
62
what are two main ways that membrane disrupting toxins work
pore (channel) former
| destruction of phospholipid bilayer (lipase activity)
63
superantigens
stimulate 20-25% of T cells
| - superantigen binds to T cell receptor and APC - binds to ones that have particular V gene segments
64
normal way T cells recognize antigen
MHC class II presneting to receptor of T cell - T cell receptor recognizes peptide bound
65
what is result of superantigens
activates a lot of T cells but they are not specific
66
what can high levels of T cells being activated to
high levels of cyokines - toxic shock (cytokine storm)
67
what is result of endotoxic shock
bulk movement of fluid from circulation into tissues
68
endotoxic shock
collapse of blood vessels - leads to disseminated intravascular coagulation - death of cells and tissue b/c of hypoxic damage
69
what does DIC stand for
disseminated intravascular coagulation
70
bactericidal drug used if it is gram neg what happens
LPS release if it is gram negative
71
endotoxins are all
polysaccharides
72
exotoins are
protein
73
endotoxin and exotoxin are both
antigenic
74
endotoxin relationship to cell
part of outer membrane
75
exotoxin relationship to cell
extracellular, diffusible
76
can endotoxin and exotoxin form toxoid?
endotoxin - no
| exotoxin - yes (vaccine)
77
special stains can be used to detect what
spores, capsule, falgellla
78
lot of method for identifying bacteria involves what
culture
79
selective media
allows growth of some species but not others
80
selective media
allows growth of some species but not others
81
list some common methods to diagnose bacterial infection
pg 62
82
what does serology tell you
if person was affected, can't tell you if person is currently affected.
only way you can say currently is if you see increase in antibiotics over certain time
83
what do you use for molecular analyses for diagnosis of bacteria
```
PCR amplification
DNA probes (in situ hybridization)
```
84
what is direct way to measure bacterial growth
microscopy
85
what is indirect way to measure bacteria growth
plate (CFU)
86
why is indirect more affective than direct (microscopy vs. plate)
on plate you are seeing live bacteria. microscopy can't distinguish
87
describe growth curve of bacterial growth
lag
exponential
stationary
death
88
describe growth curve of bacterial growth
lag
exponential
stationary
death
89
under optimal conditions what is generation time of E. Coli
15-20 minutes
90
the bacteria that causes gangrene is what kind of bacteria
anaerobe
91
what do you do with deep wound with gangrene setting in and why
open wound to let oxygen in - kills the clostridia bacteria
92
what are rapid screening assays available now called
biotyping
93
how does biotyping work
substrates that some bacteria use and some can't use
| substrates chosen so if bacteria can use them there will be colored change on strip
94
What makes up the thick peptidoglycan layer in the cell wall of both gram pos. and gram neg. bacteria?
N-acetyl muramic acid
| N-acetyl glucosamine
95
What does NAM stand for
N-acetyl muramic acid
96
What does NAG stand for
N-acetyl glucosamine
97
what will be found in gram pos but not in gram neg in peptidoglycan layer
Teichoic acids
| Lipoteichoic acids
98
exoenzymes are generally:
degradative enzymes
99
name some example exoenzymes
```
lipases
proteases
hyaluronidase
hemolysins
DNases
```
100
describe how bacteria can penetrate to subepithelial layer of host
secrete exo-enzymes that break down basement membrane
101
describe how bacteria can secrete a clot and use it to their advantage
they secrete enzyme that secretes a clot so the body's immune system can't get to the bacteria. the clot surrounds bacteria. then they secrete enzyme that initiates disassembly of the clot and bacteria can go about their business
102
high level of LPS (in cell wall of gram neg. bacteria) what happens?
high production of cytokines → can result in endotoxic shock
causes bulk movement of fluid from circulation into tissues → hypotension → collapse of blood vessels → activation of coagulation cascade → lots of coagulation in lumen of blood vessels → occludes blood tissues → hypoxic death
103
What does DIC stand for
disseminated intravascular coagulation
104
why is there DIC in endotoxic shock?
widespread release of LPS
105
bactericidal vs. bacteriostatic drug
bactericidal drug and have high level infection w/ gram neg bacteria will cause widepread release of high levels of LPS
sometimes just better to use bacteriostatic drug and leg immune system kick in
106
what is the name of the bacteria that causes gangrene
clostridia
