Bacterial Pathogens Flashcards
1
Q
prokaryotes
A
bacteria and archaea
2
Q
spirochetes
A
unusual structure
3
Q
chlamydia
A
unusual life cycle/obligate intracellular parasite
4
Q
mycobacteria
A
unusual cell wall
5
Q
mycoplasma
A
no cell wall
6
Q
staphylococcus
A
gram positive
7
Q
streptococcus
A
gram positive
8
Q
enterococcus
A
gram positive
9
Q
listeria
A
gram positive
10
Q
bacillus
A
gram positive
11
Q
corynebacterium
A
gram positive
12
Q
actinomyces
A
gram positive
13
Q
which bacteria do not stain?
A
mycobacterium, mycoplasma, spirochetes
14
Q
spirochetes example
A
borrelia, treponema, leptospira
15
Q
gram negative examples
A
salmonella, vibrio, neisseria, bordetella, e. coli, pseudomonas
16
Q
ribosomes sensitive to diptheria toxin
A
eukaryotes only
17
Q
ribosomes sensitive to cm/strep/kan
A
bacteria only
18
Q
advantages of smallness
A
nutrient acquisition and waste removal rates, smaller genome is more efficient, large surface area to volume ratio to concentrate nutrients, rapid DNA rep, rapid evolutions, high population density
19
Q
bacillus
A
rod
20
Q
coccus
A
sphere
21
Q
typical bacterial diameter
A
0.5 micrometers - 1 micrometer
22
Q
branched filamentous
A
actinomyces and nocardia
23
Q
diplococci
A
two spheres
24
Q
diplobacillus
A
two rods
25
streptococci
line of spheres
26
streptobacillus
line of rods
27
staphylococci
bundle of spheres
28
colony morphology _ relate to shape of individual bacteria
does not
29
mucoid appearance indicates _
capsule
30
waxy appearance indicates _
high lipid content - mycobacterium
31
motile organisms form _
thin, spread-out colonies
32
pigments in bacteria
protection against light, indicates where organism normally lives
33
cell envelope
cell wall, membrane, capsule, pili and flagella
34
internal structures
nucleoid, plasmid, granules, ribosomes, endosomes
35
cell envelope consists of _
cell membranes, cell wall, imbedded proteins, glycocalyx or capsule
36
cell envelope function
barrier (osmotic, pH), solute and electron transport, gradients/ATP, motility, lipid synthesis, protein secretion
37
gram positive
thick layer of exterior peptidoglycan and a cell membrane with periplasmic space in between
38
gram negative
LPS outer membrane and then a thin internal peptidoglycan layer and then cell membrane (periplasmic spaces in between)
39
gram positive cell envelope acids
teichoic and lipoteichoic acids
40
teichoic and lipoteichoic acids
give cell wall a net negative charge (Mg, Ca), covalently attached to peptidoglycan, important for serotyping, can be shed and illicit immune response, may act as adhesins, required for viability
41
are teichoic and lipoteichoic acids found in gram negative bacteria?
no
42
gram negative cell envelope
contain outer membrane porins that restrict large molecules; contain an outer membrane and cytoplasmic membrane
43
periplasmic space may contain _
virulence factors such as collagenase, hyaluronidase, beta-lactamase
44
LPS outer membrane (gram-neg)
contains oligosaccharides, core polysaccharides, divalent calcium and magnesium, lipid A
45
oligosaccharide chain
loss by pathogens will reduce virulence
46
core polysaccharides
provide resistance to hydrophobic compounds; resistance to bile acids by enteric bacteria
47
divalent calcium and magnesium
strengthen LPS intermolecular interactions; can be weakened by EDTA
48
lipid A
toxic to humans; contains only saturated fatty acids for rigidity; essential for viability
49
What antibiotics target LPS?
polymyxin antibiotics
50
lipopolysaccharides (LPS, endotoxin)
lipids + sugar; no proteins/peptides; resistant to heat, protease, autoclaving
51
O-specific polysaccharide
varies among species; useful for identification of organisms
52
core polysaccharides
glucose, galactose, heptose, KDO, glucosamine
53
lipid A is inserted _
in outer membrane
54
core an O-specific polysaccharides are _
hydrophilic with a negative charge
55
LPS actions
activates B cells, stimulates macrophages/DCs to produce cytokines, causes fever, causes leukopenia, fatal at high doses, enhances glycolysis which leads to hypoglycemia
56
septic shock/endotoxin shock
fever, chills, malaise, increased HR and RR, extreme hypotension, multiorgan failure, coagulation pathway
57
extreme hypotension in septic shock is caused by
IL-1, IL-6, TNFa
58
activation of coagulation pathway leads to _
disseminated intravascular coagulation (DIC)
59
peptidoglycan layer (murein)
critical for resistance to osmotic stress, critical target for antibiotics, permits diffusion, and has pyrogenic activity
60
peptidoglycan layer consists of _
amino acids, sugars (NAG/NAM), other molecules
61
chemical structure of peptidoglycan
N-acetylmuramic acid (NAM) is never found in eukaryotes; repeating units of NAM/NAG, D-aminos + L-aminos, diaminopimelic (DAP) (DAP in - and lysine in +)
62
lysozyme
breaks a bond in NAM; gram positive organisms are most sensitive
63
when can lysozyme cross outer membrane of gram negative bacteria?
only after osmotic shocks and EDTA treatment
64
transpeptidation reaction is inhibited by _
beta-lactam antibiotics
65
gram staining
crystal violet --> gram's iodine --> decolorizer (alcohol) --> safranin red
66
gram positive will stain _
purple
67
gram negative will stain _
red/pink
68
Which bacteria is susceptible to penicillin G?
gram positive
69
how many membranes do gram negative bacteria have?
2
70
how many membranes do gram positive bacteria have?
1
71
eukaryotic lipids
phosphatidylcholine and sterols
72
prokaryotic lipids
phosphatidylethanolamine (PE), phosphatidylglycerol (PG), cardiolipin, usually no cholesterol
73
PE is targeted by _
polymyxins
74
molecules that require active transport
ions, iron, magnesium, calcium (metals), amino acids, sugars, vitamins
75
efflux pumps allow _
resistance to antimicrobial agents
76
mycobacteria outer layer
mycolic acid; acid fast
77
mycolic acid provides _
resistance to detergents, drying, stains, common antibiotics
78
mycoplasma outer layer
triple-layered lipoprotein membrane with cholesterol
79
spirochete characteristics
endoflagella/axial filaments, corkscrew-shape, motile, outer membrane
80
Which spirochetes have LPS?
leptospira
81
chlamydia life cycle
infectious elementary body (metabolically inactive) --> reticulate body (active) --> after dividing, coverts back to EB
82
outer membrane vesicles
membrane "blebs" originating from OM of ALL gram-neg bacteria
83
OMVs contain _
adhesins, toxins, enzymes, sometimes DNA
84
extracellular vesicles
membrane vesicles produced by gram positives
85
functions of EVs/OMVs
diffuse and enter spaces too small for whole bacteria, increase toxin delivery, can contain beta-lactamase to increase resistance, transferrable DNA, might fuse with host cells
86
neisseria gonorrhoeae
utilizes an outer membrane protein that binds to factor H, increasing conversion of C3b to iC3b to inhibit MAC
87
gram positive bacteria & MAC complex
gram-pos are naturally resistant to lysis by complement due to thick peptidoglycan cell wall; can still be opsonized though
88
glycocalyx
layer or coating external to the cell wall; includes slime layers, capsules, S-layers
89
slime layers
amorphous, diffuse, thin group of EC polysaccharides, proteins, lipids
90
S-layer
defined layer of EC glycoprotein around the cell, just outside of PG layer; usually comprised of single protein
91
capsules in gram-neg
K antigen
92
K antigen
extend further out from cell surface and are important virulence factor
93
capsule virulence properties
antiphagocytic, poorly T cell immunogenic, influence adherence, partially inhibit MAC
94
capsules as vaccination tools
vaccination using purified capsular polysaccharides is effective against some important bacterial pathogens
95
major bacterial pathogens with capsule
flu type B, streptococcus pneumoniae, group A & B strep, neisseria meningitidis, salmonella, C. fetus, bacillus anthracis, pseudomonas
96
which encapsulated bacteria have a vaccine against them?
type B flu, streptococcus pneumoniae, and neisseria meningitidis
97
endospores
differentiated structures formed by gram-pos bacteria only during nutrient deprivation
98
what are endospores sensitive to?
steam, sporicidal agents, bleach, glutaraldehyde, peracetic acid, hydrogen peroxide, ethylene oxide
99
endospore core
genome with protein synthesis machinery, energy, and AA production components
100
endospore wall
peptidoglycan
101
endospore cortex
concentric layers of spore-specific peptidoglycan (thickest layer)
102
endospore coat
keratin-like protein coat with disulfide bonds for chemical strength
103
endospore exosporum
remnant of mother cell membranes
104
What is found in all endospores?
dipicolinic acid to protect DNA
105
endospore germination
activation --> germination --> outgrowth
106
endospore activation
stimulated by fresh medium, temp change, pH, or age; requires water and triggering nutrient (alanine)
107
endospore germination
cortex swells as it is rehydrated --> excretes calcium and dipicolinic acid --> loses temp resistance
108
endospore outgrowth
core enlarges, mRNA synthesis, spore coat ruptures, spore wall expanded to form new peptidoglycan
109
conjugation
transfer of plasmids between bacteria
110
antibiotics that target large subunit (50S)
chloramphenicol, clindamycin, macrolides
111
antibiotics that target small subunit
tetracycline, aminoglycosides
112
peptidoglycan and disease
sensitive to lysozyme, thick PG is complement resistant, can elicit cytokine response, unique structure allows targeting by antibiotics
113
capsules and disease
inhibit phagocytosis, poorly T cell immunogenic, partial complement resistance; vaccine target
114
plasmids and disease
confer antibiotic resistance
115
flagella and disease
motility, immunogenic, can be important for virulence
116
LPS and disease
endotoxin shock/sepsis; unique structure; targeted by polymyxin antibiotics
117
pili and disease
critical for adherence
118
endospores and disease
resistance to many microbicidal agents; environmental persistence, disease relapse
