8. Family Mycobacteriaceae (I)

Question 1

Motility of the family Mycobacteriaceae

Answer 1

Nonmotile

Question 2

What is used to stain Mycobacteria?

Answer 2

Ziel-Neelsen

Auromine O stain

Question 3

Steps in Ziehl-Neelsen acid-fast staining

Answer 3

Carbol fuchsin (1° stain)
HCl (decolorizer)
Methylene blue (counterstain)

Question 4

Found in the cell wall of Mycobacteria that enables it to retain the carbol fuchsin stain

Answer 4

Mycolic acids

Question 5

Enumerate the bacteria that have mycolic acids in their cell wall in decreasing order of chain length

Answer 5

Mycobacteria
Nocardia
Corynebacteria

Question 6

True/False. Mycobacterium tuberculosis has an animal reservoir

Answer 6

False. M. tuberculosis is an exclusive human pathogen

Question 7

An animal pathogen that is closely related to M. tuberculosis that causes a disease in people that is indistinguishable from TB

Answer 7

M. bovis

Question 8

How is M. bovis acquired?

Answer 8

Ingestion of infected meat or milk

Question 9

MOT for M. tuberculosis

Answer 9

Aerosol droplets from coughing

Question 10

Common presentation of TB

Answer 10

Chronic pulmonary disease

Question 11

Nodular structure formed by macrophages, monocytes and neutrophils which triggers an immunologic response

Answer 11

Tubercle/granuloma

Question 12

Immunologic response to M. tuberculosis infection

Answer 12

Cellular immunity

Delayed-type hypersensitivity

Question 13

What can be seen in radiographs of disseminated or miliary TB?

Answer 13

“Millet seed”-like lesions

Question 14

Dissemination of M. tuberculosis organism to the liver, spleen, kidney, bone, brain, meninges, and other parts of the lung with further granuloma formation

Answer 14

Disseminated/miliary TB

Question 15

Skin test for the delayed-type hypersentivity for TB

Answer 15

PPD test

Question 16

Antigen reagent in the PPD test

Answer 16

Purified Protein Derivative

Question 17

Vaccine for TB prophylaxis

Answer 17

Bacillus Calmette Guérin (BCG) vaccine

Question 18

Drugs taken after a positive tuberculin test to prevent disease

Answer 18

Isoniazid (INH): 6-9 months

Rifampin: 4-9 months

Question 19

M. tuberculosis drug-resistance is due to

Answer 19

Mutation

Question 20

How are nontuberculous Mycobacteria acquired?

Answer 20

Environmentally acquired

Question 21

MOTT that is commonly associated with HIV-related systemic bacterial infection; pulmonary pathogen much like TB

Answer 21

M. avium complex (MAC)

Question 22

MOTT agent of pulmonary disease in compromised hosts (HIV-infected individuals)

Answer 22

M. kansasii

Question 23

MOTT agent that causes cutaneous disease from contact with contaminated water

Answer 23

M. marinum

Question 24

MOTT agent that causes cervical adenitis in children (contaminated raw milk, soil, daily products)

Answer 24

M. scrofulaceum

Question 25

MOTT that causes skin and soft tissue diseases in various hosts

Answer 25

M. fortuitum M. chelonae M. abscessus

Question 26

MOTT agent that causes leprosy

Answer 26

M. leprae

Question 27

Nontuberculous Mycobacteria commonly found in tap water

Answer 27

M. gordonae

Question 28

Is M. gordonae pathogenic or nonpathogenic?

Answer 28

Nonpathogenic

Question 29

Class of biosafety hood in dealing with AFB

Answer 29

Class 2

Question 30

Lab diagnosis of TB

Answer 30

- AFB visible by Ziehl-Neelsen or fluorochrome smears | - recovery by culture (gold standard)

Question 31

Incubation time for Mycobacteria

Answer 31

Up to 8 weeks

Question 32

Used for rapid diagnosis of TB

Answer 32

Nucleic acid assays (NAA)

Question 33

2 species under M. avium complex (MAC)

Answer 33

M. avium | Mycoplasma intracellulare

Question 34

Most commonly isolated AFB among MOTT

Answer 34

M. avium complex

Question 35

Colony morphology of M. avium complex

Answer 35

Smooth | Cream-colored colonies

Question 36

MOTT that is rapid growing; grows in 7 days or less on solid media

Answer 36

M. fortuitum-chelonae complex

Question 37

Staining characteristics of M. fortuitum-chelonae complex

Answer 37

Gram-positive cells with diphtheroid-like morphology

Question 38

Other name for leprosy

Answer 38

Hansen's disease

Question 39

Phases of M. leprae infection

Answer 39

Silent phase | Intermediate phase

Question 40

Phase of M. leprae infection; multiplication of bacilli

Answer 40

Silent phase

Question 41

Phase of M. leprae infection; impairment of sensory and peripheral nerves

Answer 41

Intermediate phase

Question 42

Where can M. leprae be grown?

Answer 42

- Footpads of mice - Nine-branded armadillos It cannot be grown on artificial media.

Question 43

Oxygen requirements of the family Mycobacteriaceae

Answer 43

Obligate aerobes