Mycobacterium

Question 1

Identify the bacteria:

★ strictly aerobic, non-spore forming, gram (+) rods
★ rods or cocci
★ acid-fast

Answer 1

Mycobacterium

Question 2

Lipid content of cell wall is how many % of Mycobacterium’s dry weight?

Answer 2

60%

Question 3

What is responsible for Mycobacterium’s hydrophobicity, slow growth, and its resistance to acids, disinfectants, antibodies, and desiccation?

Answer 3

Lipid content of cell wall

Question 4

What are the 2 substances in Mycobacterium’s lipid?

Answer 4

mycolic acid
trehalose 6, 6’ dimycolate (cord factor)

Question 5

This classification system is based on growth rate and pigment production

Answer 5

Runyon’s Classification

Question 6

Group 1 Mycobacterium

Answer 6

Photochromogenic Strains

Question 7

Group 2 Mycobacterium

Answer 7

Scotochromogenic Strains

Question 8

Group 3 Mycobacterium

Answer 8

Non-chromogenic strains

Question 9

Group 4 Mycobacterium

Answer 9

Rapid growers

Question 10

This group of Mycobacterium grow slowly, produce yellow pigment when exposed to light, produce skin ulcers and pulmonary diseases in humans

Answer 10

Group 1: Photochromogenic Strains

Question 11

This group of Mycobacterium grow slowly, form orange-yellow pigment whether grown in light or dark, considered saprophyte

Answer 11

Group 2: Scotochromogenic Strains

Question 12

This group of Mycobacterium grow slowly, do not produce pigments, form smooth colonies, resistant to isoniazid, highly pleomorphic, produce filaments resembling Nocardia, cause pulmonary diseases in humans

Answer 12

Group 3: Non-chromogenic strains

Question 13

This group of Mycobacterium grow rapidly, mature in less than 1 week at 25-37C

Answer 13

Group 4: Rapid growers

Question 14

Mycobacteria could also be grouped as…? (3)

SOF

Answer 14

1.) saprophytes
2.) obligate parasites
3.) facultative intracellular parasites

Question 15

What are the important different Mycobacteria spp. that cause diseases in domestic animals? (5)

TAP FB

Answer 15

1.) M. avium
2.) M. tuberculosis
3.) M. paratuberculosis
4.) M. farcinogenes
5.) M. bovis

Question 16

Mycobacteria that causes disease in avians

Answer 16

M. avium

Question 17

Mycobacteria that causes disease in humans, primates, dogs, pigs, cattle

Answer 17

M. tuberculosis

Question 18

Mycobacteria that causes Johne’s disease, debilitating disease in cattle characterized by chronic/intermittent diarrhea

Answer 18

M. paratuberculosis

Question 19

Mycobacteria that causes bovine farcy (tropical countries)

Answer 19

M. farcinogenes

Question 20

Mycobacteria that causes tuberculosis in cattle, pig, cat, horses, primates, dogs, sheep; pathogenic for humans

Answer 20

M. bovis

Question 21

Mycobacteria morphology

Answer 21

short, plump rods in tissues; large, slender, and beaded in culture media; acid-fast

Question 22

Most frequently used media to culture Mycobacteria (incorporated with egg yolk) (2)

Answer 22

Dorset’s Egg Medium
Stonebrink’s Medium

Question 23

Inhibitory substance of mediums used to culture Mycobacteria

(technically, it should be “carbon source” not “inhibitory”)

Answer 23

Glycerol

Question 24

Primary culture of Mycobacteria requires _-_weeks at __C before colonies are detected

Answer 24

6-8 weeks at 37C

Question 25

colonies appearance of Mycobacteria

Answer 25

minute dull flakes that thicken into dry irregular masses rough and wavy; thick and wrinkled in fluid medium

Question 26

pigment/color of colonies of Mycobacteria

Answer 26

light yellow that progresses into deep yellow to brick red if exposed to light

Question 27

growth and elevation of colonies of Mycobacteria

Answer 27

confluent growth on surface; limited to surface unless wetting agents added

Question 28

Wetting agent added in media used for cultivation of Mycobacteria

Answer 28

Tween 80

Question 29

Antigens of Mycobacteria that makes up its cell wall (3) MWC (GMT)

Answer 29

1.) Mycosides (glycolipids) 2.) Waxes D (mycolic acid) 3.) Cord factor (trehalose 6,6 dimycolate)

Question 30

Antigen of Mycobacteria that is a protein/polypeptide released in the medium

Answer 30

Tubercuoprotein or Tuberculin

Question 31

Principal route of transmission of Mycobacteria (4) SCAM

Answer 31

1.) Sexual 2.) Congenital 3.) Aerogenous 4.) Milk borne

Question 32

Natural primary host of Mycobacteria

Answer 32

Cattle

Question 33

Do Mycobacteria have toxins / extracellular virulence factor? Yes or No?

Answer 33

No

Question 34

Cord factor present in virulent strains is important in stimulating what?

Answer 34

Granulomatous responses

Question 35

Pathogenesis of Mycobacteria (10) IA AMRF IBDB

Answer 35

1.) inhale 2.) alveolar sac 3.) alveolar macrophages 4.) multiplies & kills phagocytes 5.) reingested by macrophages 6.) filtered from regional lymphatic system 7.) intracellular multiplication 8.) bloodstream 9.) disseminated to other body sites 10.) back to lungs

Question 36

Cell's ability to prevent fusion of lysosome and phagosome, prevents intracellular digestion. This is called what?

Answer 36

Anti-fusion Effect

Question 37

Primary site of Mycobacteria

Answer 37

Tubercles form (macrophages, lymphocytes, other leukocytes)

Question 38

Sites of secondary metastasis of Mycobacteria (translucent pearly structures like small grains of tapioca)

Answer 38

Regional lymph nodes

Question 39

As growth of tubercles continues, necrosis occurs at the centers, pearls become yellow-white opaque then there is fusion/continued growth of macrophages, what are these?

Answer 39

Giant cells of Langhans

Question 40

Central part of necrotic lesions consists of very dry, cheesy material contains what?

Answer 40

Ca deposits surrounded by dense connective tissue

Question 41

Lesions in the anterior lobes

Answer 41

Caseocalcareous lesions

Question 42

Difficult to demonstrate in old lesions

Answer 42

Tubercle bacilli

Question 43

Large masses of smooth, grape-like bodies on serous surfaces

Answer 43

Tuberculous pleuritis/peritonitis

Question 44

In what animal are lesions caused by Mycobacteria can be found in lymph nodes of head, neck, abdomen?

Answer 44

Swine

Question 45

In what animal are lesions caused by Mycobacteria can be found in pharyngeal region, mesentery, lungs, liver, spleen?

Answer 45

Horse

Question 46

In what animals are lesions caused by Mycobacteria mainly pulmonary and progressive in young kids?

Answer 46

Sheep and Goat

Question 47

In what animal are lesions caused by Mycobacteria can be found in abdominal organs and lungs?

Answer 47

Cat

Question 48

Cell-mediated immune response is effective for how many weeks after infection?

Answer 48

4 weeks

Question 49

Diagnosis of Mycobacteria infection (4)

Answer 49

1.) characteristic lesion (necropsy) 2.) Ziehl-Neelsen’s staining 3.) culture, isolation, identification 4.) animal inoculation 5.) tuberculin test (M. tuberculosis & M. bovis)

Question 50

What mediums can be used to culture, isolate, & identify Mycobacteria in diagnosis? (2)

Answer 50

Lowenstein-Jensen medium Kirchner medium

Question 51

M. tuberculosis is more potent but less specific than M. bovis. True or False?

Answer 51

True

Question 52

Common sites for intradermal injection for Tuberculin Test (3)

Answer 52

Caudal fold Lip of vulva Side of the neck (most sensitive)

Question 53

After injection in Tuberculin Test, reaction is examined after how many hours?

Answer 53

72 hours

Question 54

Vaccine made from a weakened strain of M. bovis which provide protection against tuberculosis, particularly in countries where M. tuberculosis is endemic

Answer 54

BCG (Bacillus Calmette-Guérin)

Question 55

Other methods of Tuberculin Test (3)

Answer 55

Ophthalmic Test Thermal Test Stormont Test

Question 56

Involves two injections of tuberculin at same site; reaction is examined after 7 days

Answer 56

Stormont Test

Question 57

Runyon's classification under Group 3, morphology is more variable in shape than M. bovis, strongly acid & alcohol fast,

Answer 57

Mycobacterium avium

Question 58

Mycobacterium avium cultural growth and colony appearance

Answer 58

less than 1 week, well developed in 2 weeks colonies are soft, moist, yellow that becomes yellowish to pinkish with age and exposure to light

Question 59

Antigens of Mycobacterium avium (3)

Answer 59

1.) M. intracellulare complex of serotypes 1-21 2.) serotypes 1-2 (chicken & avian) 3.) serotype 3 (cattle)

Question 60

Immunity of Mycobacterium avium

Answer 60

cell mediated and humoral

Question 61

On what medium is Mycobacterium avium isolated on for diagnosis?

Answer 61

Dorset’s medium