Streptococcus Pneumoniae, B. Pertussis, Mycobacterium

Question 1

Main cause of community acquired pneumonia worldwide. Also causes otitis media (in kids) and meningitis in adults.

Answer 1

Streptococcus pneumoniae

Question 2

4 Stages of Pathogenesis of Streptococcus Pneumoniae:

Answer 2

1. Alveoli fill with fluid
2. Early consolidation phase (suppurative inflammation)
3. Late consolidation phase (alveoli and airways are packed with neutrophils, affected tissue is solid not spongy)
4. Recovery phase (macrophages phagocytose debris, normal architecture re-established)

Question 3

____ is a parasite of Protozoa found in contaminated water and spread by environmental aerosols. Virulent strains multiply within ____ (double membrane of rough ER)

Answer 3

L. Pneumophila (Legionella Pneumophila)

Autophagosomes

Question 4

L. Pneumophila:
1. Effective Drugs

2. Ineffective Drugs

Answer 4

1. Macrolides, Fluoroquinolones, Tetracyclines (intracellular penetration)
2. Penicillins (not effective because they don’t achieve therapeutic concentrations in macrophages)

Question 5

Streptococcus Pneumoniae:

1. Gram stain?
2. Oxygen dependence?
3. Can it be isolated? How?

Answer 5

1. Gram positive
2. Aerotolerant anaerobe
3. Yes, Catalase negative -> optochin susceptibility

Question 6

Major reservoirs of Streptococcus Pneumoniae:

Answer 6

• Young kids
• Nasopharyngeal mucosa

Transmitted by respiratory secretions/hands

Question 7

Legionella Pneumophila:

1. Gram stain?
2. Oxygen dependence?
3. Can it be isolated? How?

Answer 7

1. Gram negative
2. Obligate aerobe
3. Yes, fastidious (special conditions for cultivation in lab), cysteine requirement is identifying characteristic

Question 8

Legionella pneumophila: Virulence/Proinflammatory mechanisms:

Answer 8

1. Survival in macrophages

2. LPS, Flagellin (enhances inflammation)

Question 9

Bordetella Pertussis and Parapertussis

1. Gram stain?
2. Oxygen dependence?
3. Can it be isolated? How?
4. Reservoir?

Answer 9

1. Gram negative
2. Obligate aerobe
3. Nasal swab (culture)
4. Adults (nasopharynx)

Question 10

Very contagious bacteria, cause of Whooping Cough

Answer 10

Bordetella pertussis and parapertussis

Question 11

B. pertussis vs. P. Parapertussis toxin production:

Answer 11

B. Pertussis: pertussis toxin, adenylate cyclase/hemolysin, endotoxin

P. Parapertussis: no pertussis toxin

Question 12

Clinical course of Whooping Cough:

Answer 12

1. Catarrhal stage (very runny nose, very contagious)
2. Paroxysmal Stage (whooping coughs)
3. Convalescent stage (gradual recovery)

Question 13

Mycobacterium spp.

1. Gram stain?
2. Oxygen dependence?
3. Can it be isolated? How?
4. Diseases
5. Encounter thru

Answer 13

1. Gram negative
2. Obligate aerobes
3. Very slowly
4. Tuberculosis, Leprosy
5. Ingestion/Inhalation

Question 14

Milder disease form of M. Leprae. May be self limiting. Very few bacteria present in lesions.

Answer 14

Tuberculoid Leprosy

Question 15

Severe form of M. Leprae. Disfiguring, many organisms in lesions, cell mediated immunity decreased.

Answer 15

Lepromatous Leprosy