MYCOBACTERIA

Question 1

Mycobacteria tuberculosis

Characteristics

Answer 1

Acid fast
Obligate aerobe

Question 2

Mycobacteria tuberculosis

Grows in

Answer 2

Löwenstein-Jensen medium

Question 3

Mycobacteria tuberculosis

Transmission

Answer 3

Respiratory droplets

Question 4

Mycobacteria tuberculosis

Virulence factors

Answer 4

Cord factor: creates serpentine cord, increases TNF-alpha activation that activates more macrophages increasing granuloma formation

Sulfatides: inhibits phagolysosomal fusion (allows to survive inside macrophages)

Question 5

Mycobacteria tuberculosis

What is formed in primary infection?

Answer 5

Ghon complex: hilar nodes + ghon focus (mid/lower lobes)

Question 6

Mycobacteria tuberculosis

From primary infection, what is the evolution of disease?

Answer 6

90%: healing by fibrosis and calcification (latent)
10%: progressive primary tuberculosis (AIDS, malnutrition)

Question 7

Mycobacteria tuberculosis

Where does the bacteria remains latent?

Answer 7

Caseating granuloma: broken down necrotic macrophages (usually in upper loves)

Question 8

Mycobacteria tuberculosis

Serology in latent TB infection

Answer 8

PPD (+)
Interferon-y release assay (IGRA) (+)

Question 9

Mycobacteria tuberculosis

Risk factor for TB reactivation

Answer 9

Immunocompromised individuals (HIV, organ transplant recipients, TNF-alpha use)

Question 10

Mycobacteria tuberculosis

How the use of TNF- alpha is related to TB reactivation?

Answer 10

TNF-alpha allows granuloma formation and macrophages activation containing the TB inside granuloma. If it is inhibited , it allows dormant TB to escape

Question 11

Mycobacteria tuberculosis

Where does the reactivation of TB occurs?

Answer 11

Upper lobes

Question 12

Mycobacteria tuberculosis

Signs and symptoms

Answer 12

Cough, night sweats, hemoptysis, weight lose

Question 13

Mycobacteria tuberculosis

Treatment

Answer 13

RIPE
Rifampicin, Isoniazid, Pyrazinamide, Ethambutol

Question 14

Mycobacteria tuberculosis

Positive PPD

Answer 14

Size of induration: >15 mm at 48-72 hours

Question 15

Mycobacteria tuberculosis

What can cause a false positive PPD

Answer 15

BCG vaccination

Question 16

Mycobacteria leprae

Characteristics

Answer 16

Acid fast
Grows in cold temperatures

Question 17

Mycobacteria leprae

Major reservoir

Answer 17

Armadillos

Question 18

Mycobacteria leprae

Other name for leprae

Answer 18

Hanson’s disease

Question 19

Mycobacteria leprae

2 clinical presentations

Answer 19

Tuberculoid
Lepromatous

Question 20

Mycobacteria leprae

Tuberculoid presentation

Clinic

Answer 20

Hypoesthetic, hairless skin plaques

Question 21

Mycobacteria leprae

Tuberculoid presentation pathology

Answer 21

High cell-mediated immunity with large Th1 response and low bacterial load

Question 22

Mycobacteria leprae

What do you use to diagnose Tuberculoid leprae?

Answer 22

Lepermans skin test

Question 23

Mycobacteria leprae

Lepromatous presentation

Answer 23

Glove and stocking pattern
Leonine facies

Question 24

Mycobacteria leprae

Lepromatous presentation pathology

Answer 24

Low cell- mediated immunity with large Th2 response > bacteria being unable to contained in macrophages

Question 25

# Mycobacteria leprae Treatment

Answer 25

Dapsone and rifampicin for tuberculoid form (6 months) Clofamizine is added in lepromatous form (2-5 months)