Micro: TB Flashcards Preview

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Flashcards in Micro: TB Deck (17):
1

Component of Mycobacterium tuberculosis cell wall that is stained.

Mycolic acid
(acid fast stain)

2

Virulence factor for TB

Chord Factor

3

What are the 3 types of tuberculosis?

1. Primary: initial infection
2. Secondary: reactivation of initial infection
3. Miliary: disseminated to multiple organ systems

4

Describe the pathogenesis of TB.

-TB enters the lung tissue
-alveolar macrophages engulf TB but it survives
-TB multiplies within macrophages further attracting more macrophages to the site to infect
-Granuloma forms with a center of necrosis (casesating)
-Granuloma remains dormant for years until a stimulus reactivates it

5

Describe the changes in Tubercles (granulomas) during a TB infection over time.

Caseous lesion: cheese-like
Ghon Complex: lungs and lymph node infected
-calcified caseous lesion
Tuberous cavities: tubercle that liquefies and forms air-filled cavity

6

What are the steps for Dx of TB?

Step 1: PPD test (type IV hypersensitivity)
Step 2: if step one is (+) then do a CXR

7

Which agar plate can diagnose TB?

Lowenstein-Jensen agar

8

What is Tx for a patient diagnosed with TB?

4 drugs in combination (RIPE)
1. Rifampin
2. Isoniazid
3. Pyrazinamide
4. Ethambutol
(done for 6 months total)

9

Tx for people exposed to TB infected pts.

Isoniazid

10

Treatment program for pts infected with multi-drug resistant (MDR) TB or XDR-TB.

DOTS: Directly Observed Treatment Short course

11

Who is at risk for developing Mycobacterium avium complex (MAC) pneumonia?

IC
Chronic lung disease

12

Primary MAC pneumonia is similar to TB pneumonia. Who is at risk of developing secondary or disseminated MAC pneumonia?

AIDS pts with T cell count below 50 cells/ml

13

Tx for MAC pneumonia

1. Clarithromycin or Azithromycin
+
2. Ethambutol
+
3. Rifampin

14

Prophylaxis for AIDS pts to prevent MAC infection

Clarithromycin or Azithromycin

15

Weakly acid fast gram (+) aerobe with branching filament pattern.

Nocardia sp.

16

Complication of Nocardosis

Can spread from the lungs and form abscesses in the brain or kidneys

17

Tx for Nocardosis

TMP-SMX