TB/Non-TB Myco (lec 14)

Question 1

TB difficult to eradicate, why?

Answer 1

Non-compliance w/ long tx
Resistant
HIV co-inf
140 species

Question 2

M. TB microbe characteristics?

Answer 2

Acid-fast Bacillus
Obligate Aerobes
Non-motile
Heat sensitive
Intracellular growth

Question 3

M. TB agar?

Colonies?

Answer 3

Lowenstein-Jense
Middlebrooks

ruff, buff, tuff

Question 4

M. TB epidemiology?

Answer 4

Infants/Old, immuno
Reservoir: human (U) young adult carriers
Transmission: p-to-p, aerosol droplet

Question 5

M.TB factors affecting probability of spread?

Answer 5

of mocrobes
Duration/Conditions of exposure
Strain

Question 6

M. TB virulence factors?

Answer 6

1) Mycolic acids (protect microbe)

2) Cord Factor (Mycoside):
produces parallel growth of bacteria

3) Sulfatides (attach to Cords, protect/promote)
4) Lipoarabinomannan (Φ host immunity)

Question 7

M. TB: (P) responses to bacteria? (4)

Answer 7

1) Immediate innate clearance
2) º disease (immediate onset)
3) Latent (immun system containment)
4) Endogenous/2º (activation of latent)

Question 8

M. TB º Infection presentation?

Answer 8

PNA-like sxs
Macro w/ MTB to perihilar lymph node -> LAD
Apical lungs (highest O2)

Question 9

M. TB immune response?

???? slide 38-41

Answer 9

macrophages present MTB antigens ->
T-cells sensitized to MTB 2-6wks ->
release lymphokines ->
attract/activate macrophages ->
destroy MTB w/ lytic enzymes/ROI/RNI ->
granulomas ->
caseous necrosis of tissue

Question 10

M. TB immune response results in what test results?

Answer 10

TST = +
IGRA = +

Question 11

M. TB antigen?

Answer 11

ESAT-6

Question 12

Miliary TB is?

Answer 12

(Millet-seed sized granulomas)

Multi-organ vascular destruction

Question 13

Pott Disease TB is?

Answer 13

MTB in vertebral bodies

Chronic back pain/destruction

Question 14

M. TB diagnostics?

Answer 14

Rapid MTB/RIF system = identifies TB and Rif resistance

Question 15

M. avium/intracellulare (MAC) microbe characteristics?

Answer 15

Acid-fast bacilli
Weakly G+
Aerobic

Question 16

MAC agar?

Answer 16

Middlebrook:

Flat, translucent, smooth colonies (egg-like)
No cording/clustering

Question 17

MAC epidemiology?

Answer 17

Ubiquitous (H2O, soil, plants)
Opportunistic (U) HIV
Transmission: inhalation/ingestion, NO p-to-p

Question 18

MAC presentation: HIV - pts?

Answer 18

Plumonary sxs:
(U) elderly M w/ COPD or W w/ bronch dz

Lymphadenitis:
1-4yo

Question 19

MAC presentation: HIV + pts?

Answer 19

fever, wt loss, night sweats, DIARRHEA

NEW dz, not activation of latent
Colonization of GI -> hemat spread

Granulomas can’t kill -> disseminated MAC ->
multi-system ->↓ CD4

Question 20

MAC diagnostics?

Answer 20

r/o other causes
CXR = pulmonary lesions
ID pathogen (PCR) = 16s rRNA

Question 21

MAC tx: HIV -

HIV +

Answer 21

Clarith/Azith + Etham until sputum clear for 1 yr

Clarith/Azith + Etham + Rif

Question 22

HIV + w/ NTM and no MAC tx?

w/ NTM and MAC?

Answer 22

chemoprophy until CD4 > 100 for 3 months

Clarith/Azith + Etham + Rif for 2 wks
THEN ADD ART (don’t start at same time)