Medical Microbiology > L19 > Flashcards

L19 Flashcards

(58 cards)

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1
Q

True or False: Non-bacterial agents (viral) are responsible for majority of URI

A

True

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2
Q

Bronchitis, Bronchiolitis, and Pneumonia are infections of the ___
A. URT
B. LRT

A

B. LRT

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3
Q

True or False: Oral and nasal cavities have natural flora, but the URT is sterile

A

False - while oral/nasal cavities have NF, the LRT is sterile

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4
Q

Which two pathogens can cause URT infection in the throat – specifically 1) Strep throat and 2) Diptheria?

A

1) Strep throat - S. pyogenes

2) Diptheria - Corynebacterium diptheria

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5
Q

True or False: Pneumonia, Whooping Cough, and Tb or LRT infections

A

True

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6
Q

True or False: Mycobacterium tuberculosis causes: TB or Chronic pneumonia

A

True

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7
Q

Mycoplasma,
Ureaplasma, and Chlamydia, Legionella are all atypical pneumonias, which can cause __ infection
A. URT
B. LRT

A

B. LRT

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8
Q

Bordetella pertussis can cause which LRT infection?
A. Pneumonia
B. Whooping Cough
C. Strep

A

B. Whooping Cough

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9
Q

What is the #1 bacterial agent of pharyngitis?
A. Mycoplasma
B. Streptococcus pyogenes
C. Cutibacterium acnes
D. Strep aureus

A

B. Streptococcus pyogenes
- Group A Strep
- Gram-positive cocci, chains

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10
Q

Which three adhesions (microbial surface components recognizing adhesive matrix molecules) are used by S. pyogenes for virulence?

A
  1. M protein
  2. Fibronectin and Collagen binding protein
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11
Q

Which three strategies are used by S. pyogenes to evade host immune
response?

A
  1. Capsule (contains HA)
  2. M Protein (antigenic variation)
  3. C5a Peptidase
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12
Q

True or False: S. pyogenes uses toxins (SPE) and enzymes (e.g - Streptolysin S and O; Streptokinase)

A

True

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13
Q

What is the function of Streptolysin S and O + Streptokinase in S. pyogenes?

A

Streptolysin S and O = Lyse RBC

Streptokinase = Activates plasminogen to plasmin to dissolve clots

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14
Q

True or False: In addition to causing strep, S. pyogenes can cause Scarlet Fever + Necrotizing Fascitis

A

True

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15
Q

What happens if you don’t treat pharyngitis (aka - secondary sequlae)?

A
  1. Scarlet Fever - SPE
  2. Rheumatic Fever
  3. AGN
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16
Q

If pharyngitis goes untreated, Rheumatic fever could develop, leading to “molecular mimicry” in which Abs for GAS cross-react
with the host ___ tissue

A

Cardiac

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17
Q

Deposition of antigen-Abs for GAS in the
glomerular basement membrane activate
complement and induces inflammation. This can result when ___ is not treated

A

Pharyngitis

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18
Q

Complications of S. pyogenes infection?

A
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19
Q

S. pyogenes lab diagnosis?

A
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20
Q

Chart

A
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21
Q

True or False: Immunization is important for avoiding Corynebacterium infection

A

True

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22
Q

True or False: Corynebacterium diptheria occurs in palisades and is a gram (+) pleomorphic rod

A

True

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23
Q

C. diptheria uses an AB toxin. B binds to ___ while A is ___ portion/inactivates ___

A

receptor/heparin-binding epidermal GF (heart and nerves); enzymatic; EF-2

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24
Q

True or False: C. diptheria uses toxin carried on a bacteriophage; regulated by iron

25
Under what conditions will C. diptheria not transcribe toxin genes?
When there's enough Fe - Both Fe/DtxR will bind to toxin operator
26
True or False: Under low Fe conditions, there is release of DtxR (diptheria toxin repressor) -- which allows for transcription of toxin gene
True
27
Why is C. diptheriae infection associated with painful swallowing?
- Leads to pseudomembrane formation (bacteria, plasma cell, dead cells)
28
Which test can be used to dx C. diptheria?
Elek Test
29
True or False: In bronchiolitis, airway becomes obstructed from swelling of bronchiole walls
True
30
Which gram (-) cococobacilli is the causative agent of Pertussis/Whooping cough? Where does it adhere?
Bordetella pertussis - Adheres to: ciliated epithelial cells in trachea
31
True or False: Pertussis/Whopping Cough mostly affects trachea and bronchi
True
32
What MOA is used by B. pertussis to cause airway swelling?
Makes A-B5 type toxin that binds to G-alpha inhibitory subunit Increases cAMP and mucous production, as well as death/sloughing of infected cells
33
What is the most contagious stage of Pertussis? A. Common Cold B. Paroxysmal cough C. Convalescent stage
A. Common Cold
34
Stages of Pertussis?
Common Cold, Paroxysmal Cough, and Convalescent Stage
35
How do organisms enter lung to cause pneumonia?
1) Aspiration - S/K pneumo 2) Inhalation of aerosols 3) Hematogenous - S. aureus
36
Pneumonia is associated with necrotic/apoptotic type _ cells
1
37
Which two extracellular bacteria cause Typical pneumonia (lobar)?
K/S Pneumoniae
38
Which two agents cause Host-compromised Pneumonia (cancer)?
Nocardia + P. aero
39
Atypical (interstitial) pneumonia can be caused by which three agents?
1. Legionella 2. Mycoplasma 3. Chylamydia
40
Chronic pneumonia is caused by which 2 anaerobes?
1) Fungi 2) M. tuberculosis
41
Consolidation/Lobar Pneumonia is associated with which Gram positive bacteria?
S. pneumo
42
Which gram (+) bacteria is the major cause of community-acquired pneumonia? Why are epidemics unlikely in this case?
S. pneumo - Due to aspiration (not contagious!)
43
S. pneumo features?
Gram (+) Lancet shape Encapsulated diplococci Catalse/coag (-)
44
What is major virulence factor used by S. pneumo?
Capsule polysaccharide - basis of vaccine
45
Rusty colored sputum suggets ___ pneumonia
Lobar/Consolidation
46
S. pneumo dx?
47
True or False: Atypical Pneumonias are fastidious, grow slow, and lack peptidoglycan layer
True - also, most cause destruction of ciliated respiratory epithelium
48
True or False: M. pneumo and U. urealyticum are extracellular pathogens while Chlamydia are obligate intracellular
True
49
True or False: Only M. pneumo and C. pneumo are transmitted person to person -- U. urealyticum and C. trachomatasis are transmitted vertically
True
50
True or False: M. tuberculosis is associated with chronic pneumonia
True - Note: AFB (+)
51
True or False: M. tuberculosis do NOT have gram stain and do NOT grow on blood agar -- there cell contains mycolic acid
True
52
True or False: Mycobacteria are often referred to as acid-fast bacilli (AFB)
True - rod shaped - resistant to decolorization by acid
53
What primary stain can bind to mycolic acid in mycobacteria?
Carbolfuschin - decolor = acid OH - counter = meth blue
54
Which two virulence factors are used by mycobacteria (M Tb)?
1. mycolic acid 2. cord factor - glycolipid found in cell wall
55
True or False: M Tb is INTRACELLULAR BACTERIA + primary defense is cell mediated ( T cell )
True
56
True or False: M Tb induces hypersensitivity + it can replicate/survive in macrophages (facultative intracellular)
True
57
Blood sputum suggests __
Tb
58
Tb dx?
Medical Microbiology
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