L19 Flashcards
True or False: Non-bacterial agents (viral) are responsible for majority of URI
True
Bronchitis, Bronchiolitis, and Pneumonia are infections of the ___
A. URT
B. LRT
B. LRT
True or False: Oral and nasal cavities have natural flora, but the URT is sterile
False - while oral/nasal cavities have NF, the LRT is sterile
Which two pathogens can cause URT infection in the throat – specifically 1) Strep throat and 2) Diptheria?
1) Strep throat - S. pyogenes
2) Diptheria - Corynebacterium diptheria
True or False: Pneumonia, Whooping Cough, and Tb or LRT infections
True
True or False: Mycobacterium tuberculosis causes: TB or Chronic pneumonia
True
Mycoplasma,
Ureaplasma, and Chlamydia, Legionella are all atypical pneumonias, which can cause __ infection
A. URT
B. LRT
B. LRT
Bordetella pertussis can cause which LRT infection?
A. Pneumonia
B. Whooping Cough
C. Strep
B. Whooping Cough
What is the #1 bacterial agent of pharyngitis?
A. Mycoplasma
B. Streptococcus pyogenes
C. Cutibacterium acnes
D. Strep aureus
B. Streptococcus pyogenes
- Group A Strep
- Gram-positive cocci, chains
Which three adhesions (microbial surface components recognizing adhesive matrix molecules) are used by S. pyogenes for virulence?
- M protein
- Fibronectin and Collagen binding protein
Which three strategies are used by S. pyogenes to evade host immune
response?
- Capsule (contains HA)
- M Protein (antigenic variation)
- C5a Peptidase
True or False: S. pyogenes uses toxins (SPE) and enzymes (e.g - Streptolysin S and O; Streptokinase)
True
What is the function of Streptolysin S and O + Streptokinase in S. pyogenes?
Streptolysin S and O = Lyse RBC
Streptokinase = Activates plasminogen to plasmin to dissolve clots
True or False: In addition to causing strep, S. pyogenes can cause Scarlet Fever + Necrotizing Fascitis
True
What happens if you don’t treat pharyngitis (aka - secondary sequlae)?
- Scarlet Fever - SPE
- Rheumatic Fever
- AGN
If pharyngitis goes untreated, Rheumatic fever could develop, leading to “molecular mimicry” in which Abs for GAS cross-react
with the host ___ tissue
Cardiac
Deposition of antigen-Abs for GAS in the
glomerular basement membrane activate
complement and induces inflammation. This can result when ___ is not treated
Pharyngitis
Complications of S. pyogenes infection?
S. pyogenes lab diagnosis?
Chart
True or False: Immunization is important for avoiding Corynebacterium infection
True
True or False: Corynebacterium diptheria occurs in palisades and is a gram (+) pleomorphic rod
True
C. diptheria uses an AB toxin. B binds to ___ while A is ___ portion/inactivates ___
receptor/heparin-binding epidermal GF (heart and nerves); enzymatic; EF-2
True or False: C. diptheria uses toxin carried on a bacteriophage; regulated by iron
True
Under what conditions will C. diptheria not transcribe toxin genes?
When there’s enough Fe
- Both Fe/DtxR will bind to toxin operator
True or False: Under low Fe conditions, there is release of DtxR (diptheria toxin repressor) – which allows for transcription of toxin gene
True
Why is C. diptheriae infection associated with painful swallowing?
- Leads to pseudomembrane formation (bacteria, plasma cell, dead cells)
Which test can be used to dx C. diptheria?
Elek Test
True or False: In bronchiolitis, airway becomes obstructed from swelling of bronchiole walls
True
Which gram (-) cococobacilli is the causative agent of Pertussis/Whooping cough? Where does it adhere?
Bordetella pertussis
- Adheres to: ciliated epithelial cells in trachea
True or False: Pertussis/Whopping Cough mostly affects trachea and bronchi
True
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
What is the most contagious stage of Pertussis?
A. Common Cold
B. Paroxysmal cough
C. Convalescent stage
A. Common Cold
Stages of Pertussis?
Common Cold, Paroxysmal Cough, and Convalescent Stage
How do organisms enter lung to cause pneumonia?
1) Aspiration - S/K pneumo
2) Inhalation of aerosols
3) Hematogenous - S. aureus
Pneumonia is associated with necrotic/apoptotic type _ cells
1
Which two extracellular bacteria cause Typical pneumonia (lobar)?
K/S Pneumoniae
Which two agents cause Host-compromised Pneumonia (cancer)?
Nocardia + P. aero
Atypical (interstitial) pneumonia can be caused by which three agents?
- Legionella
- Mycoplasma
- Chylamydia
Chronic pneumonia is caused by which 2 anaerobes?
1) Fungi
2) M. tuberculosis
Consolidation/Lobar Pneumonia is associated with which Gram positive bacteria?
S. pneumo
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!)
S. pneumo features?
Gram (+)
Lancet shape
Encapsulated diplococci
Catalse/coag (-)
What is major virulence factor used by S. pneumo?
Capsule polysaccharide
- basis of vaccine
Rusty colored sputum suggets ___ pneumonia
Lobar/Consolidation
S. pneumo dx?
True or False: Atypical Pneumonias are fastidious, grow slow, and lack peptidoglycan layer
True
- also, most cause destruction of ciliated respiratory epithelium
True or False: M. pneumo and U. urealyticum are extracellular pathogens while Chlamydia are obligate intracellular
True
True or False: Only M. pneumo and C. pneumo are transmitted person to person – U. urealyticum and C. trachomatasis are transmitted vertically
True
True or False: M. tuberculosis is associated with chronic pneumonia
True
- Note: AFB (+)
True or False: M. tuberculosis do NOT have gram stain and do NOT grow on blood agar – there cell contains mycolic acid
True
True or False: Mycobacteria are often referred to as acid-fast bacilli (AFB)
True
- rod shaped
- resistant to decolorization by acid
What primary stain can bind to mycolic acid in mycobacteria?
Carbolfuschin
- decolor = acid OH
- counter = meth blue
Which two virulence factors are used by mycobacteria (M Tb)?
- mycolic acid
- cord factor
- glycolipid found in cell wall
True or False: M Tb is INTRACELLULAR BACTERIA + primary defense is cell mediated ( T cell )
True
True or False: M Tb induces hypersensitivity + it can replicate/survive in macrophages (facultative intracellular)
True
Blood sputum suggests __
Tb
Tb dx?
