Exam 3: Mycobacteria

Question 1

Mycobacteria species are weakly

Answer 1

gram positive

Question 2

what type of laboratory method is needed to see mycobacteria?

Answer 2

acid-fast

Question 3

acid-fast organisms appear ____ against a ____ background

Answer 3

red; blue

Question 4

mycobacteria species are strict

Answer 4

aerobes

Question 5

mycobacteria species produce

Answer 5

catalase

Question 6

t/f mycobacteria species have capsules, spores, and toxins

Answer 6

false

Question 7

t/f mycobacteria species grow very slowly in culture and usually require an enriched culture

Answer 7

true

Question 8

what are mycobacteria species cell walls composed of

Answer 8

peptidoglycan layer similar to other gram +, mycolic acids (long chain fatty acids), lipid polysaccharide complex functionally similar to LPS layer of gram -

Question 9

mycobacterium tuberculosis is what type of pathogen

Answer 9

facultative intracellular pathogen

Question 10

The captain of death

Answer 10

mycobaterium tuberculosis

Question 11

virulence factor of mycobacteria species

Answer 11

mycolic acids + LPC layer form a WAXY COAT

Question 12

waxy coat is

Answer 12

hydophobic, hardy, impenetrable, resistant to dry, common disinfectants and acids

Question 13

MTB allows itself to be engulfed by

Answer 13

alveolar macrophages but then can block the destruction of the phagosome that it is hiding in

Question 14

white plague

Answer 14

mycobacterium tuberculosis

Question 15

1 infectious disease worldwise

Answer 15

mycobacterium tuberculosis

Question 16

who accounts for 50% of mycobacterium tuberculosis cases in the U.S. today?

Answer 16

immigrants

Question 17

mycobacterium tuberculosis is transmitted primarily by

Answer 17

airbone respiratory droplets

Question 18

usually requires crowded, indoor conditions with repeated exposure

Answer 18

mycobacterium tuberculosis

Question 19

rate of infectivity is high, but rate of disease is low

Answer 19

mycobacterium tuberculosis (only 5% of infected people develop active/clinical disease)

Question 20

where must mycobacterium tuberculosis (bacilli) make it after being inhaled to cause infection?

Answer 20

alveoli

Question 21

When bacilli reach alveoli and are phagocytosed by alveolar macrophages, these three possible outcomes can occur:

Answer 21

1. immediate clearance of the organism
2. primary disease
3. latent infection

Question 22

primary disease TB

Answer 22

IMMEDIATE ONSET of active disease

Question 23

symptoms of primary disease TB

Answer 23

hemoptysis, night sweats, weight loss, lymphadenopathy, unintentional weight loss, fatigue

Question 24

which of the three possible outcomes is most common?

Answer 24

latent infection

Question 25

multiples within the alveolar macrophages and remains contained inside for long periods --> travels inside the macrophages to infect other organs

Answer 25

primary TB

Question 26

as the bacteria (in primary TB) multiply in the lungs, the macrophages can release cytoines -->

Answer 26

attract T cells and other inflammatory cells to the site

Question 27

granulomas occur with which TB

Answer 27

primary TB

Question 28

granuloma

Answer 28

inflammatory cells are fused together -- multinucleated giant cell that surround the bacilli

Question 29

as granuloma grows, center becomes necrotic and is called ______, bc of the cheesy, semisolid character of the material at the center

Answer 29

caseous necrosis

Question 30

most of the clinical manifestations of primary TB results from

Answer 30

damage caused by the host response, not the bacilli themselves

Question 31

typical host of primary TB

Answer 31

50 y.o. man who just immigrated to the U.S.

Question 32

immune response "wins" and stops the growth and multiplication of MTB inside macrophages --> some organisms enter an INACTIVE, DORMANT STATE

Answer 32

latent TB

Question 33

reactivation TB only occurs in

Answer 33

10% of cases (not common)

Question 34

when someone gets primary TB when they are younger and then the disease reactivates years later when they are immunocompromised

Answer 34

reactivation TB

Question 35

reactivation TB thought to be due to

Answer 35

waning immunity

Question 36

where is the most common reactivation site for reactivation TB due to aerobic/favorable environment

Answer 36

apex of lungs

Question 37

during initial infection or upon reactivation, bacilli can DISSEMINATE to regional lymph nodes, kidneys, bones, genital tract, bowel, brain/meninges

Answer 37

extrapulmonary TB

Question 38

where extrapulmonary TB is most serious

Answer 38

TB meningitis

Question 39

dx gold standard for mycobacterium TB

Answer 39

sputum culture for mycobacteria with AFB smear

Question 40

what might someone see on a chest xray of someone with TB?

Answer 40

ghon complex (when granuloma centers get necrotic so they eat their way through the bronchiole and calcify)

Question 41

Tuberculin skin testing aka

Answer 41

PPD/Mantoux test

Question 42

what does the PPD test identify?

Answer 42

latent TB in asymptomatic patients with possible history of exposure

Question 43

PPD

Answer 43

purified protein derivative (is a tuberculin protein)

Question 44

tuberculin protein that gets injected is an antibody or antigen?

Answer 44

antigen

Question 45

PPD results read how many hours after injection?

Answer 45

48-72

Question 46

positive result PPD

Answer 46

individual has been infected with MTB at some point -- does NOT discriminate between active and inactive disease

Question 47

negative result PPD

Answer 47

no contact or infection (also may be - in immunocompromised patient who is unable to react to the antigen)

Question 48

CI to PPD test

Answer 48

history of BCG vaccine (may cause a systemic reaction or severe ulceration and necrosis at the test site)

Question 49

BCG

Answer 49

Bacille Calmette Guerin

Question 50

when and where is the BCG vaccine usually given?

Answer 50

newborns in areas of the world where TB prevalance is high

Question 51

BCG vaccine contains live strains of

Answer 51

M. bovis

Question 52

True/falase, mycobacterium leprae cannot grow on artificial media or tissue culture bc it is an obligate intracellular parasite

Answer 52

true

Question 53

cannot reproduce outside their host cell

Answer 53

obligate intracellular parasite

Question 54

how long is the incubation period for mycobacterium leprae?

Answer 54

7 years

Question 55

leprosy aka

Answer 55

Hansen's bacillus or Hansen's disease

Question 56

virulence factor of mycobacterium leprae

Answer 56

waxy coat (mycolic acids + LPC layer)

Question 57

naturally infects aramadillos

Answer 57

mycobacterium leprae

Question 58

a chronic disease that begins in the skin and mucous membranes --> progresses int onerves

Answer 58

Hansen's disease/leprosy

Question 59

infectivity is low; must have prolonged close contact

Answer 59

mycobacterium leprae

Question 60

mycobacterium leprae is spread through

Answer 60

direct inoculation and droplet inhalation

Question 61

2 forms of mycobacterium leprae

Answer 61

tuberculoid | lepromatous

Question 62

tuberculoid mycobacterium leprae

Answer 62

causes development of macules or plauqes of face, trunk, and extremities --> bacteria invade peripheral nerves --> thickens nerve sheaths and causes loss of sensation

Question 63

small number of organisms present in lesions; not as contagious

Answer 63

tuberculoid (mycobacterium leprae)

Question 64

causes a deeply nodular, diffuse, extensive infection that causes severe disfigurement of the face and extremeties; can lead to loss of nasal bones and digits

Answer 64

lepromatous (mycobacterium leprae)

Question 65

M. leprae grows in

Answer 65

cooler regions of the body (nose & ears esp.)