Lower Respiratory Tract Infections (LRTIs)

Question 1

What microorganism causes tuberculosis?

Answer 1

Mycobacterium tuberculosis (MTB)

Question 2

Describe the morphology of MTB

Answer 2

Bacillus, non-motile, acid fast (no G), obligate aerobe

Question 3

What does MTB produce that causes bacteria to clump + inhibits phagocytosis?

Answer 3

Cord factor

Question 4

Does MTB produce toxin?

Answer 4

No

Question 5

What forms an impermeable barrier around MTB?

Answer 5

Mycolic acid

Question 6

What is the major pathogenic mechanism of MTB?

Answer 6

Inflammation

Question 7

How is TB transmitted?

Answer 7

Airborne

Question 8

What are the 3 outcomes after TB?

Answer 8

• Latent infection
• Primary tubercle forms
• Spread of active infection

Question 9

Describe latent infection

Answer 9

TB enters macrophages and remain

Question 10

Describe primary infection

Answer 10

Host cell isolates the infection in a tubercle (granuloma)

Question 11

Why can’t TB replicate inside tubercles?

Answer 11

Low pH + low oxygen

Question 12

When does a disseminated infection (miliary tuberculosis) occur?

Answer 12

If tubercle doesn’t form or if it ruptures

Question 13

Describe second stage infection

Answer 13

Spread of tubercles from primary infection or reactivation of latent infection

Question 14

Is MTB present in both TB latent infection and active disease?

Answer 14

Yes

Question 15

What are the results of a Tuberculin Skin Test for TB latent infection and active disease?

Answer 15

Latent: positive
Active: negative

Question 16

Describe chest x-ray results for TB latent infection and active disease

Answer 16

Latent: normal
Active: reveals lesion

Question 17

What are the results of a sputum smear & culture for TB latent infection and active disease?

Answer 17

Latent: negative
Active: positive

Question 18

Describe the symptoms of TB latent infection and active disease

Answer 18

Latent: none
Active: cough, fever, weight loss

Question 19

Are TB latent infection and active disease infectious?

Answer 19

Latent: no
Active: infectious before treatment

Question 20

Are both TB latent infection and active disease defined as cases of TB?

Answer 20

Latent: no
Active: yes

Question 21

What are the 6 methods of diagnosing TB?

Answer 21

• Acid-fast rods in sputum
• Culture
• QuantiFERON Gold
• Skin test
• Tuberculin test
• Mantoux test

Question 22

What is the vaccine for TB called?

Answer 22

BCG (Bacillus Calmette-Guerin)

Question 23

When is BCG used?

Answer 23

High risk children in NA (not effective

Question 24

Causes of pneumonia in adults are mainly ____ whereas in children are mainly ____

Answer 24

bacterial, viral

Question 25

What microorganism causes typical pneumonia?

Answer 25

S. pneumoniae

Question 26

Describe the Gram morphology & characteristics of Streptococcus pneumoniae

Answer 26

Facultatively anaerobic, G+, diplococci

Question 27

Does S. pneumoniae respond to penicillin?

Answer 27

Yes

Question 28

S. pneumoniae often spreads to blood, causing:

Answer 28

Bactermia, speticemia, sepsis

Question 29

What 2 types of vaccine does typical pneumonia have?

Answer 29

- Polysaccharide (23 types) | - Conjugate (13 types)

Question 30

What are symptoms of typical pneumonia?

Answer 30

Fever, rust colored sputum, breathing problems + chest pain

Question 31

What are 6 factors that contribute to S. pneumoniae's pathogenicity?

Answer 31

- Capsule - Cell wall - Choline binding proteins - Autolysins - Pneumolysins - Production of OH, neuraminidase, IgA protease

Question 32

What are the 5 viruses that can cause atypical pneumonia discussed in class?

Answer 32

- Bronchiolitis - RSV (Respiratory Syncytial Virus) - Croup - Covid-19 - Influenza A

Question 33

What demographic does bronchiolitis affect?

Answer 33

Children <2 years

Question 34

Describe bronciolitis

Answer 34

- Inflamed bronchioles result in reduced oxygen intake | - Necrosis of epithelial cells

Question 35

How is RSV transmitted?

Answer 35

Direct contact + droplet

Question 36

What demographic does RSV affect?

Answer 36

Children <5 years & elderly

Question 37

What is the treatment for RSV?

Answer 37

None + no vaccine

Question 38

What are the symptoms for RSV?

Answer 38

Coughing, wheezing

Question 39

What causes RSV?

Answer 39

Enveloped RNA virus

Question 40

What causes croup?

Answer 40

Parainfluenza virus (PIV), enveloped RNA

Question 41

Describe croup

Answer 41

Swelling of mucous membranes in respiratory tract

Question 42

What demographic does croup affect?

Answer 42

Children

Question 43

What causes Covid-19?

Answer 43

Sars-CoV-2

Question 44

What is the main receptor for Covid-19 in humans?

Answer 44

Angiotensin convernting enzyme 2 (ACE2)

Question 45

ACE2 normally breaks down ____ but when Covid-19 binds to ACE2, ____ is destructive

Answer 45

ANG II, ANG II

Question 46

What are the glycoprotein spikes on the Covid-19 virus responsible for?

Answer 46

Tropism + attachment to host cell

Question 47

What is influenza A caused by?

Answer 47

Segmented RNA viruses

Question 48

How long is the incubation period for influenza A?

Answer 48

1-5 days

Question 49

How is influenza A transmitted?

Answer 49

Droplet

Question 50

What is antigenic drift?

Answer 50

- Point mutations in viral genome | - Require new vaccines

Question 51

What is antigenic shift?

Answer 51

- Recombination of viral RNA segments (significant changes) | - Leads to pandemics

Question 52

What are 4 fungi that can cause atypical pneumonia?

Answer 52

- Histoplasmosis - Coccidioidomycosis - Aspergillosis - Pneumocystis jiroveci

Question 53

Does atypical pneumonia respond to penicillin?

Answer 53

No, resistant