B4.3 BIOCHEMICAL AND INHIBITION TEST FOR MYCOBACTERIUM

Question 1

BIOCHEMICAL TESTS used for Mycobacterium

Answer 1

a. Niacin Accumulation
b. Nitrate Reduction
c. Catalase Test
d. Tween 80 Hydrolysis
e. Iron Uptake
f. Arylsulfatase
g. Pyrazinamidase
h. Tellurite Reduction
i. Urease

Question 2

What is the result of Niacin Accumulation for M. tuberculosis?

Answer 2

Positive result: Yellow color

Question 3

Reagents of Niacin Accumulation for M. tuberculosis?

Answer 3

Cyanogen Bromide and Aniline

Question 4

Niacin Accumulation Performed on

Answer 4

L-J medium, cultures at least 3 weeks old and with at least 50 colonies

Question 5

Most commonly used for M. tuberculosis

Answer 5

Niacin Accumulation

Question 6

Nitrate Reduction test principles

Answer 6

Nitroreductase catalyzes the reduction of nitrate to nitrite

Question 7

Nitrate Reduction test Reagents

Answer 7

Hydrochloric acid,
Sulfanilamide,
N-(1-naphthyl)enediamine dihydrochloride

Question 8

Nitrate Reduction test Indicator

Answer 8

Zinc

Question 9

Nitrate Reduction test Positive result

Answer 9

Red color

Question 10

Nitrate Reduction test Positive organisms

Answer 10

M. kansasii,
M. szulgai,
M. fortuitum, and
M. tuberculosis

Question 11

Measurement of the height of the oxygen bubble column formed by untreated enzyme

Answer 11

Semiquantitative Catalase Test

Question 12

What are the results for the Semiquantitative Catalase Test

Answer 12

<45 mm of bubbles = Negative
45 mm of bubbles = Positive

Question 13

What are the conditions for the Semiquantitative Catalase Test?

Answer 13

Addition of Tween 80 and hydrogen peroxide

Question 14

Tests the ability of catalase enzyme to remain active after heating at 68°C for 20 minutes

Answer 14

Heat-stable Catalase Test

Question 15

Heat-stable Catalase Test Positive result spp present

Answer 15

M. tuberculosis,
M. bovis,
M. gastri,
M. haemophilum,
M. marinum remain active

Question 16

Tween 80 Hydrolysis principle

Answer 16

Lipase hydrolyzes Tween 80 into oleic acid and polyoxyethylated sorbitol

Question 17

pH indicator used in Tween 80 Hydrolysis

Answer 17

Neutral Red bound to Tween 80

Question 18

Tween 80 Hydrolysis Positive result

Answer 18

Pink color

Question 19

Tween 80 Hydrolysis Positive organisms

Answer 19

M. asiaticum,
M. gastri,
M. marinum,
M. malmoense,
M. scrofulaceum,
M. flavescens,
M. terrae;
M. kansasii

Question 20

Iron Uptake test principle

Answer 20

Converts ferric ammonium citrate to an iron oxide

Question 21

Iron Uptake test Positive result

Answer 21

Rusty brown colonies

Question 22

What does the Iron Uptake test distinguish

Answer 22

M. chelonae (-) from other rapid growers (+)

Question 23

What is the biochemical reaction for Arylsulfatase?

Answer 23

Breaks down phenolphthalein disulfate into phenolphthalein

Question 24

Arylsulfatase Positive result

Answer 24

Pink color

Question 25

Arylsulfatase Reagents

Answer 25

Tripotassium phenolphthalein sulfate and sodium bicarbonate

Question 26

Arylsulfatase Positive organisms

Answer 26

M. fortuitum complex, M. chelonae, M. xenopi, M. triviale (3 days); M. marinum and M. szulgai (14 days)

Question 27

Pyrazinamidase activity principle

Answer 27

Hydrolyzes pyrazinamide to pyrazinoic acid and ammonia

Question 28

Pyrazinamidase activity Positive result

Answer 28

Red pigment formed with ferrous ammonium sulfate

Question 29

Pyrazinamidase activity Distinguishes

Answer 29

M. marinum from M. kansasii and M. bovis from M. tuberculosis

Question 30

What is the biochemical result in the Tellurite Reduction test?

Answer 30

>reduction of colorless POTASSIUM TELLURITE to BLACK METALLIC TELLURIUM in 3 to 4 days

Question 31

Tellurite Reduction test Positive result

Answer 31

Black color within 3-4 days

Question 32

Tellurite Reduction test Distinguishes

Answer 32

MAC from other nonchromogenic species

Question 33

What species are able to reduce tellurite within 3 days

Answer 33

All rapid growers

Question 34

What is the Urease test used to differentiate?

Answer 34

Distinguishes M. scrofulaceum (+) from M. gordonae (-)

Question 35

Urease test Positive result

Answer 35

Pink to red color

Question 36

->differentiates MTB from the scotochromogens and MAC

Answer 36

Nitrate Reduction

Question 37

Nitrate Reduction operating principle

Answer 37

>incubated in 2 ml of sodium nitrate at 37? C for 2 hours

Question 38

>differentiates species of photochromogens, nonchromogens, and scotochromogens

Answer 38

Tween 80 Hydrolysis

Question 39

What are the inhibitory tests used for the identification of mycobacteria?

Answer 39

NAP (p-nitroacetylamino-Bhydroxypropiophenone) Thiophene-2-Carboxylic Acid Hydrazide (TCH) Sodium Chloride Tolerance Growth on MacConkey Agar

Question 40

is a precursor in the synthesis of chloramphenicol

Answer 40

NAP (p-nitroacetylamino-Bhydroxypropiophenone)

Question 41

NAP (p-nitroacetylamino-Bhydroxypropiophenone) test Selectively inhibits

Answer 41

M. tuberculosis complex

Question 42

NAP reagent

Answer 42

5 mg of NAP in BACTEC-NAP vial

Question 43

NAP Specimen

Answer 43

Colonies from agar or broth in BACTEC medium

Question 44

NAP Positive result

Answer 44

20% increase in growth index (indicates M. tuberculosis complex)

Question 45

What does Thiophene-2-Carboxylic Acid Hydrazide (TCH) test differentiate?

Answer 45

Distinguishes M. bovis (Sensitive) from M. tuberculosis (Resistant)

Question 46

What does the Sodium Chloride Tolerance test inhibit

Answer 46

Inhibits M. flavescens, M. triviale, and most rapidly growing Mycobacterium species

Question 47

Sodium Chloride Tolerance test component

Answer 47

5% NaCl in egg-based media

Question 48

What is the result of Growth on MacConkey Agar for M. fortuitum-chelonae complex?

Answer 48

Positive result: Growth in 5 days Negative result: Group IV rapid growers do not grow on MacConkey agar