Exam 1 Flashcards
(117 cards)
1
Q
Bacteria can be polycistronic. What does this mean?
A
More than one protein is encoded on a single mRNA
2
Q
What are mycoplasms?
A
smallest and simplest bacteria and lack a cell wall
contain sterol in the membrane
3
Q
What the obligate intracellular bacteria?
A
Rickettsiae and Chlamydiae
4
Q
What does autotrophic mean?
A
organisms that derive their energy from either sunlight or inorganic compounds in order to synthesize complex organic compounds
5
Q
In regard to energy sources, what are most animals and fungi classified as?
A
chemoorganoheterotrophs
6
Q
What does heterotrophic mean?
A
organisms that are unable to create their own energy and have to derive it from other complex organic organisms
7
Q
What are facultative anaerobes?
A
can survive in aerobic or anaerobic environments
8
Q
What is quorum sensing?
A
when bacteria exploit cell to cell communication in order to regulate transcription
9
Q
What bacteria utilizes clumping factor A to bind to fibrinogen?
A
S. aureus
10
Q
What bacteria utilizes MSCRAMM to bind to ECM components?
A
Staphylococcus spp.
11
Q
What type of bacteria use LTA + M protein, protein F or MSCRAMM to bind ECM?
A
Group A strep
12
Q
In a UTI infection, E coli utilizes what adhesion method?
A
P fimbriae to adhere P blood group glycolipids
13
Q
What bacteria adhere to N acetylhexosamine-galactose?
A
S. pneumoniae
14
Q
E. coli utilize type 1 fimbriae to adhere to
A
D-mannose
15
Q
Shigella adheres to integrins on _____ of intestinal cells which causes?
A
M cells to cause actin polymerization to induce engulfment
16
Q
Once shigella is in a cell, how does it harm the cell?
A
it activates apoptosis
17
Q
Shigella can be classified as a _____ intracellular bacteria.
A
facultative
18
Q
What enzymes do S. aureus use to protect itself from host defenses?
A
coagulases
19
Q
S. pyrogenes produces what enzyme to break down clots the body has formed to isolate the infection?
A
streptokinase
20
Q
What do coagulases do?
A
convert fibrinogen into fibrin (forms clots)
21
Q
What does streptokinase do?
A
converts plasminogen into plasmin (breaks down clots)
22
Q
Streptococci, staphylococci and C. perfringens all utilize what enzyme to promote their spread throughout the body?
A
hyaluronidase
23
Q
How does Clostridia facilitate the spread of gas gangrene?
A
collagenase
24
Q
Lipoprotein is associated with what bacteria?
A
gram negative
25
Lipoteichoic acid is associated with what bacteria?
gram positive
26
O antigens within the LPS are associated with what kind of bacteria?
gram negative
27
What is the primary mechanism of pathogenicity for streptococci?
M protein
28
What type of bacteria secrete siderophores and when?
Gram negative
when they need iron
29
How do siderophores work?
they have a higher affinity for iron and steal it from iron transport ps
30
What bacteria are known for ingesting iron transport proteins in order to take in their iron?
N. gonorrhoeae, N. meningitidis
31
What does direct damage mean?
bacteria use the host cell's nutrients and produce waste
32
What are exotoxins?
proteins produced IN the bacteria and then released out of the cell
33
What are endotoxins?
lipid A of the outer membrane of the LPS of gram negative and released when the cell wall lyses or breaks apart
34
Once toxins are released, what do they do?
elicit an inflammatory response and activates the complement system
35
What toxin was well known during WWII?
C. tetani
36
How does vaccination work for toxin-producing bacteria?
it neutralizes the toxin if you become infected
37
What are toxoids?
inactivated exotoxins given as a vaccine
38
What are the 3 types of exotoxins?
A-B toxins
Membrane disrupting toxins
Superantigens
39
What type of exotoxins are superantigens?
type I exotoxins
40
How C. tetani toxin work?
1. uptake of toxin into motor neuron
2. subunit A exits endosome
3. transported to inhibitory neuron
4. subunit A cleaves synaptobrevin
5. fuses with neurotransmitter vesicle (GABA or glycine) to BLOCK its release
6. ACh continuously released at synaptic cleft
7. muscle cell stays continually contracted causing spastic paralysis
41
How does C. diphtheriae toxin work?
1. subunit B binds cell
2. A-B subunits taken into cell
3. subunit A is released into cytoplasm
4. subunit A attaches an ADP ribosyl group to EF2 to INHIBIT it
5. Arrests protein synthesis by hindering translation
42
How does C. botulinum toxin work?
Similar to C. tetani but blocks the release of ACh so it INHIBITS muscle stimulation causing flaccid paralysis
43
How does V. cholerae toxin work?
1. subunit B binds the cell's ganglioside molecules
2. Fragment A1 enters the cell
3. A1 causes ADP-ribosylation of the Gs alpha subunit ps
4. Gs alpha can no longer convert GTP to GDP
5. Gs alpha stays active and increases adenylate cyclase
6. HIGH concentration of cAMP over activates PKA
7. PKA then phosphorylates CTFR
8. efflux of Cl- and water into lumen leads to diarrhea
44
How does S. dysenteriae toxin work?
1. AB subunits bind Gb3 on cell
2. A subunit converts to N-glycosidase
3. eliminates 1 adenine from 28S rRNA
4. inhibition of translation leads to cell death
45
How do the C. perfringens toxins work?
CPE binds
alpha toxin- lecithinase that damages cell membranes
beta toxin- maybe pores??
epsilon toxin- membrane pores
theta toxin- necrotizing hemolysin
delta toxin- hemolysin
46
How does L. monocytogenes toxins work?
1. produce membrane attack ps
2. these lyse phagolysosome membranes
3. microbes are released into cytoplasm and propegate listeriolysin O and phospholipases
4. secrete more membrane attack ps causing release of microbes from phagocyte
5. infection of neighboring cells
47
How does C. diff toxins work?
inhibits Rho activation so GTPases cannot convert GTP to GDP
48
Streptolysin O (SLO) is inactivated by
O2
49
Streptolysin S (SLS) is stable in the presence of
O2
50
Streptolysin S (SLS) is stable in the presence of
O2
51
How do S. aureus toxins work?
damage the desmosomes that hold skin cells together leading to scalded skin syndrome (exfoliative toxin)
52
How does B. anthracis toxin work?
EF and LF bind PA and are transferred to cytoplasm
EF binds calmodulin and activates adenylate cyclase leading to over production of cAMP
LF cleaves MAPKK disrupting cell signals and leading to cell death
53
How does B. pertussis toxin work?
toxin binds Gi alpha subunit blocking GDP to GTP
it can no longer regulate adenylate cyclase
this leads to an over production of cAMP
54
A patient presents with thrombocytopenia, hemolytic anemia and kidney failure. What disease do you suspect and what causes it?
hemolytic uremic syndrome (HUS) caused by E. coli verotoxins
55
A patient comes in with gastroenteritis due to eating soup on a buffet. What was the cause?
C. perfringens
56
What causes TSST-1?
S. aureus
57
What is the most common cause of food poisioning?
S. aureus
58
What pathogen would produce a positive catalase test?
Staph aureus
59
A lower UTI is usually caused by?
E. coli
60
A UTI can progress into pyelonephritis. What is the usual cause?
E. coli
61
Proteus UTI infections are positive for
urease
62
What color do gram negatives stain?
purple
63
What are bacterial cell walls composed of?
peptidoglycan NAG & NAM lattices
64
What connects NAG and NAM rows?
tetrapeptides D&L
65
What does DAP of gram negs adhere to?
D-alanine
66
Gram positive cell walls contain several layers of
peptidoglycan
67
Gram pos cell walls contain
teichoic acid OR lipoteichoic acid
68
What is teichoic acid?
glycerol-phosphate repeats
69
What is the purpose of teichoic acid in GRAM POS?
1. bind and regulate movement of cations
2. provide rigidity
3. antigenicity
70
Gram negs cell walls contain
an outer membrane consisting of LPS
71
Where are peptidoglycans located in bacteria?
cytoplasmic membrane
72
Archaea have what kind of cell walls?
no cell wall OR pseudomurein
**NO PEPTIDOGLYCAN**
73
What identifies mycobacteria?
acid fast staining ***CARBOFUCHSIN & HEAT***
74
Where is the periplasmic space?
Between outer membrane and cytoplasmic membrane
75
Why do mycobacteria not stain easily?
a lot of lipids in cell wall that prevents entry of Gram stain
76
In order for gram negs to be effected by lysozymes, what do the cells need to be treated with first?
EDTA to chelating cations
77
How does penicillin work?
it destroys the peptidoglycan cross bridges
78
What diseases does S. aureus cause?
ASSIST-
```
A- acute endocarditis
S- scalded skin syndrome
S- Staph pneumonia
I- impetigo
S- staph food poisoning
T- TSS
```
79
What does S. epi cause?
infection of prosthetic heart valves
infection of catheters and shunts
80
What would be the positive test results of S. aureus culture?
grAm positive
catAlase positive
coAgulase postive
81
What would be the test results of S. epi?
catalasE positive
| urEase positive
82
What does S. saprophyticus cause?
UTIs
83
What is S. saprophyticus resistant to?
novobiocin
84
What does S. pyrogenes cause?
NPSRPP- Nice Posie Sent Ryan Pretty Golfballs
```
N- necrotizing fasciitis
P- pharyngitis
S- scarlet fever
R- rheumatic fever
P- pericarditis
G- glomerulonephritis
```
85
What does S. pneumoniae cause?
MOP
M- meningitis
O- otitis media
P- pneumococcal pneumonia
86
What is the main virulence factor of S. pneumoniae?
polysaccharide capsule
87
Why do capsules contribute to virulence?
They avoid phagocytosis
88
What are the common signs of scarlet fever and what causes it?
erythmatous rash, strawberry tongue, peeling skin
caused by pyrogenic exotoxin of S. pyrogenes
89
What does S. viridans cause?
bacterial endocarditis **dental work**
90
What does S. mutans cause?
dental caries
91
What organism can lead to neonatal meningitis that is transferred during birth?
S. agalactiae **Group B**
92
At a potluck, rice is left sitting out on a table for several hours. Everyone ends up with watery diarrhea and nausea shortly after eating. What caused this and what is the virulent mechanism?
Bacillus cereus due to the spores/exotoxins
93
How does tetanus cause disease?
spores found in soil release tetanospasmin toxin which INHIBITS GABA/Glycine release so ACh is continuously released and the muscle stays contracted
94
How does C. botulin cause disease?
It blocks the release of ACh so muscles cannot contract--- flaccid paralysis
95
What does C. perfringens cause?
abdominal pain and diarrhea-- 8-12 hr incubation
96
Where is C. perfringens common?
meats, stews, poultry left warm for too long
97
What does C. diptheriae cause?
grey exudate on tonsils or grey sores on skin
98
What can H. influenzae cause?
COPE
C- conjunctivitis
O- otitis media
P- pneumonia
E- epiglottitis
99
What causes ophthalmia neonatum and hyperacute conjunctivitis?
N. gonorrhea
100
What are the gram positive bacteria other than staphs and streps?
B. cereus
C. tetanus
C. botulin
C. perfringens
C. diff
C. diphtheriae
101
What toxin inhibits elongation factor 2?
C. diphtheriae
102
What toxins have A & B subunits?
diphtheria, tetani, botulin, shiga, S. aureus exfoliative, anthrax, cholera, pertussis
103
What toxins cause cAMP to overproduce?
cholera, pertussis, and EF of anthrax
104
C. perfringens has several toxin forms. What is the alpha toxin mechanism?
lecithinase causes massive hemolysis, bleeding, heart and liver issues
105
How does the C. perf enterotoxin work?
breaks occludins between intestinal cells
106
What are the membrane disrupting toxins?
C. diff, staph and strep, mono, and C. perf
107
Which bacteria produce leukocidins?
staph and strep
108
Which streptolysin (strep hemolysin) is unstable in O2?
streptolysin O
109
What bacteria produce toxins that lyse phagolysosomes?
Listeria mono
110
Which bacteria inhibits GTPases inhibiting Rho?
C. diff
111
Which bacteria produce superantigens?
S. aureus and Beta hemolytic strep
112
What type of bacteria produce EXOtoxins?
Gram +
113
What bacteria produce ENDOtoxins?
Gram -
114
Which bacteria evade phagocytosis?
M protein of S. pyrogenes and pili of N. gonorrhea
115
What is the purpose of protein A for S. aureus?
binds Fc portion of IgG preventing complement activation
116
What bacteria produce capsules?
THE LUNG & BRAIN DISEASE ONES- pneumonia, anthrax, meningitis, Hib
117
Which bacteria produce spores
only gram + Clostridium and Bacillus species
