Mycobacteria

Question 1

generation time for Mtb

Answer 1

15-20 hours - colonies need 4-6 weeks to appear

Question 2

Can you culture M. Leprae in vitro?

Answer 2

No

Question 3

Which mycobaceria have human and animal hosts

Answer 3

M. Leprae, and Mtb complex

NOT NTB - environmental/watery habitats

Question 4

TB affects what proportion of world’s pop

Answer 4

1/3 - 22 countries bear 80% of burden

Question 5

reported cases of TB in canada are accounted for by

Answer 5

66% of foreign born indviduals

Question 6

How is TB transmitted?

Answer 6

Airborne! droplet nuclei

Question 7

M. bovis can cause infection i

Answer 7

GI and tonsils

Question 8

Some key factors that increase risk of transmission of TB

Answer 8

cavitary lung disease

laryngeal disease

Question 9

Primary focus of a TB infection is

Answer 9

Middle and lower lung lobes

Question 10

Secondary foci of TB infection are

Answer 10

- everywhere!
Upper lungs
LN
vertebral bodies
meninges

Question 11

What % of TB will go on to develop primary disease

Answer 11

only 5%

Question 12

Miliary TB is

Answer 12

TB in whole body

Question 13

If you have NO disease or a latent infection your skin test will be

Answer 13

positive

Question 14

What is the risk if reactivation of latent TB

Answer 14

5% within first 2 years, then then additional 5% for rest of lifetime
In HIV 10% per year

Question 15

The antibody response to TB has

Answer 15

NO role in host defence

Question 16

Cell mediated immunity usually plays

Answer 16

The biggest role - delayed type 4 hypersensitivity

Question 17

How long does cell-mediated immunity take to develop?

Answer 17

3-9 weeks

8% of people revert to negative after 1 year

Question 18

what immune mechanism inhibits intracellular replication of Mtb

Answer 18

activation of monocytes with TNFa

Question 19

Which cytokines are preferentially expressed following a Th1 CD4 cell response

Answer 19

IL-2
IFN-gamma
IL-12

Question 20

What cytokine may suppress the immune response

Answer 20

IL-10

Question 21

How large is the induration in mantoux test

Answer 21

10mm

5mm if HIV positive

Question 22

what % of people will be skin test negative with active disease

Answer 22

15-20%

may be falsely negative if immunocompromised

Question 23

For a latent TB test you can use what to diagnose

Answer 23

IFN-gamma assay production of T cells

Question 24

Vaccine for TB is

Answer 24

live attenuated M. bovis
60-80% effective in children
DOES NOT prevent infection

Question 25

What does the vaccine for TB do?

Answer 25

prevents progression to clinical disease

Question 26

Where is M. Leprae commonly found

Answer 26

in nasal secretions - likely airborne

Question 27

where can you grow M. Leprae

Answer 27

Footpads of mice
nine-banded armadillo
- better at low temps -

Question 28

How does M. Leprae resist killing

Answer 28

Surface phenolic glycolipid resists oxidative stress

Question 29

Which disease has a DTH reaction - tuberculoid or Lepromatous?

Answer 29

Tuberculoid

Question 30

Which disease has a vigorous CMI reaction (similar to reactivation of TB) tuberculoid or Lepromatous?

Answer 30

Tuberculoid

Lepromatous more IL-10 produced less IL-1

Question 31

Which disease has a large number of lesions - tuberculoid or Lepromatous?

Answer 31

Lepromatous

Question 32

Which disease causes local anesthesia - tuberculoid or Lepromatous?

Answer 32

Tuberculoid

Question 33

Which disease is similar to miliary TB - tuberculoid or Lepromatous?

Answer 33

Lepromatous

Question 34

which mycobaterium has to be environmentally acquires

Answer 34

M avium complex

M. intracellulare and M. avium

Question 35

Mycobacterium of which type can look like a disseminated TB infection

Answer 35

M avium complex in HIV positive individuals

Question 36

which two mycobacteria part of the MtB complex

Answer 36

M. bovis

M. tuberculosis

Question 37

what % of people will reactivate TB

Answer 37

5% of the 95% that had latent infection