Daniels-Pneumo, etc

Question 1

Strep. pneumoniae characteristics

Answer 1

Gram + cocci
Diplococci
Aerotolerant anaerobe
Non-spore forming
Encapsulated

Question 2

Main cause of pneumonia

Answer 2

S. pneumoniae

Question 3

S. pneumoniae identification tests

Answer 3

Alpha hemolysis
Neg catalase test
Zone of inhibition

Question 4

S. pneumoniae Reservoir and transmission

Answer 4

Young children are reservoir
Nasopharyngeal mucosa
Transmission via respiratory secretions/hands

Question 5

S. pneumoniae pathogenesis

Answer 5

1) Alveoli fill w/ fluid
2) Early consolidation phase
- Suppurative (neutrophils) inflammation
3) Late consolidation phase
- Alveoli and airways packed w/ neutrophils
- Affected tissue is solid instead of spongy
4) Recovery phase
- Macrophages phagocytose debris
- Normal architecture re-established

Question 6

S. pneumoniae disease manifestations other than pneumonia

Answer 6

• otitis media in children
• Potential sequelae to pneumonia in adults
  
  • Pleural effusion-fluid in chest outside of lungs
  • bacteremia-meningitis

Question 7

S. pneumoniae diagnosis

Answer 7

gram stained sputum and culture

Question 8

S. pneumoniae therapy

Answer 8

• Penicillins and other B-lactams (resistance is concern)
• Macrolides (erythromycin, azithromycin)
• Fluoroquinolones (levofloxacin)

Question 9

S. pneumoniae vaccine

Answer 9

Made from polysaccharide (capsular) antigens from multiple strains of S. pneumoniae.
-Given to children and elderly

Question 10

Legionella pneumophila characteristics

Answer 10

Gram -
Pleomorphic rod
Obligate aerobe
Fastidious
Cysteine requirement-imp. for identification

Question 11

L. pneumophila encounter

Answer 11

Think hot tub:

• Contaminated water
• L. pneumophila is a parasite of protozoa
• Biofilms w/ protozoa and other bacteria
• Thermotolerant
• Environmental aerosol spread (not by cough)

Question 12

L. pneumophila multiplication

Answer 12

• Bacteria in alveoli are phagocytosed

- Virulent strains multiply in autophagosomes

Question 13

L. pneumophila pathogenesis

Answer 13

Inflammation->acute bronchopneumonia

• Suppurative (neutrophils)
• Recruitment of more macrophages (L. pneumophila multiply in autophagosomes)
• Abscess formation

Question 14

Immune response to L. pneumophila

Answer 14

Cell mediated immune response

• Secretion of IFN-gamma
• Iron sequestration (decreases replication of bacteria)

Question 15

L. pneumophila virulence

Answer 15

• Survival in macrophages
• LPS
• Flagellin (enhances inflammation via TLR-5 of innate immune system)

Question 16

L. pneumophila therapy

Answer 16

Need antimicrobial drugs w/ good intracellular penetration
-Macrolides
-Fluoroquinolones
-Tetracyclines
Penicillins NOT effective b/c do not penetrate macrophages enough

Question 17

Bordetella pertussis and parapertussis characteristics

Answer 17

Gram - rod
Obligate aerobe
Causes whooping cough
Very contagious

Question 18

B. pertussis reservoir

Answer 18

Adults are reservoir

Nasopharynx

Question 19

B. pertussis entry/transmission

Answer 19

Access trachea/bronchi
 -Ciliary adherence via:
    *Filamentous hemagglutinin (Fha)
    *Pili
    *Pertactin protein
Think B. pertussis adheres w/ FhaPP

Question 20

B. pertussis vs B. parapertussis

Answer 20

*Difference-B. parapertussis does not have pertussis toxin
*Similarities
-Adenylate cyclase/ hemolysin
-Upregulate host cAMP
>Decreased neutrophil function
>Inc. capillary permeability (edema)
-Endotoxin

Question 21

B. pertussis pathogenesis

Answer 21

1) Catarrhal stage (1-2 weeks)
- Looks like bad cold, really runny nose
- Organisms spreading down respiratory tract
- Extremely contagious
2) Paroxysmal stage (1-6 weeks)
- Fits of whooping coughs w/ vomiting
3) Convalescent stage (2-3 weeks)
- Gradual recovery

Question 22

B. pertussis diagnosis

Answer 22

• Tricky b/c fewer organisms are shed in paroxysmal stage, when clinical suspicion is high.
• Deep nasal swab or nasal flush
• Can diagnose 3 weeks prior to cough

Question 23

B. pertussis vaccine

Answer 23

• Contain acellular pertussis
• dTAP-given to young
• Tdap-given to older and during pregnancy
  
  • Lower dose of diptheria and pertussis

Question 24

B. bronchiseptica

Answer 24

Canine tracheobronchitis–kennel cough

Only affects immunocompromised humans

Question 25

Mycobacterium species

Answer 25

TB:
  -M. tuberculosis
  -M. bovis
  -M. avium
Leprosy:
  -M. leprae
Opportunistic deep wound infections:
  -RGM (rapidly growing mycobacterium)

Question 26

Mycobacterium spp.characteristics

Answer 26

Obligate aerobes
Non-spore formers
Thick, waxy cell wall–acid fast
*Mycolic acid binds carbol fuscin dye. Not gram stained!

Question 27

Mycobacterium spp.encounter, multiplication and spread

Answer 27

1) Ingestion->localization in intestine->adequate cell mediated immunity should kill via macrophages->Latency->Reactivation by 2nd TB->Dissemination in intestine and spread to other organs
2) Inhalation->lesion in lung->adequate cell mediated immunity should kill via macrophages->Latency->Reactivation by 2nd TB->Dissemination in lung and spread to other organs

Question 28

M. tuberculosis pathogenesis/immune response

Answer 28

• Multiplication in macrophages
• Activation of CD4
• Cytokines: IFN-gamma, IL-12, IL2
• Macrophage recruitment forms granuloma

Question 29

M. tuberculosis diagnosis

Answer 29

Intradermal test:
  -Killed tuberculin antigen
  -DTH (type IV hypersensitivity)
     *Activation of specific CD4
Acid fast sputum exam
Culture-very slow growing
PCR

Question 30

M. leprae spread and disease characteristics

Answer 30

Granulomatous disease
 -Similar immunology to TB (granulomas)
Affects skin b/c bacteria prefers cooler temps
Spread via respiratory route
Two forms:
  1)Tuberculoid leprosy
  2)Lepromatous leprosy

Question 31

Tuberculoid leprosy vs lepromatous leprosy

Answer 31

Tuberculoid leprosy:
  -Milder
  -May be self limiting
  -Few bacteria in lesions
Lepromatous leprosy:
  -Severe disfiguring
  -Many organisms in lesions
  -Cell mediated immunity significantly decreased

Question 32

M. leprae cultivation

Answer 32

Uncultivatable in vitro
Can inoculate mouse footpad
Armadillos are carriers