Mycobacterium

Question 1

What kind of bacteria are Mycobacterium?

Answer 1

Mycolic acid, gram + rods, acid fast +, aerobic, facultative intracellular pathogen

Question 2

What is the importance of Mycobacterium?

Answer 2

Human and bovine tuberculosis

Question 3

What kind of infections do Mycobacterium cause?

Answer 3

Chronic granulomatous infections

Question 4

What are 2 virulence factors of Mycobacterium?

Answer 4

1. Mycolic acid containing cell wall lipids

2. Cell protein antigens

Question 5

T/F: Under optimum conditions, obligate pathogens can survive in a contaminated environment for extended periods

Answer 5

True

Question 6

T/F: Many species of Mycobacterium are soil and water saprophytes that can opportunistically infect susceptible hosts

Answer 6

True

Question 7

What are 4 important disease caused by Mycobacterium?

Answer 7

1. Mammalian tuberculosis
2. Avian tuberculosis
3. Leprosy
4. Johne’s disease

Question 8

Which two Mycobacterium are in the tuberculous group and form caseous granulomas?

Answer 8

1. M. tuberculosis

2. M. bovis

Question 9

Which Mycobacterium is in the tuberculous group and forms non caseous granulomas?

Answer 9

M. avid complex

Question 10

Which immune response is important in the destruction of bacilli?

Answer 10

Cell mediated immune response

Question 11

What type of hypersensitivity is caused by Mycobacteria?

Answer 11

Type IV or Delayed type hypersensitivity

Question 12

What is the classic lesion of tuberculosis?

Answer 12

Tubercles

Question 13

What are the characteristics of tubercles?

Answer 13

Granulomas with epithelioid macrophages (hard) or caseous necrosis (soft) surrounded by multinucleate giant cells

Question 14

What re elements of a tubercle?

Answer 14

Activated macrophages/epithelioid cells

Lymphocytes

Fibrosis

+/- Mineralization

+/- Coagulative/caseous/liquefactive necrosis

Question 15

Who is the main reservoir for tuberculosis?

Answer 15

Humans

Question 16

Is TB a treatable and curable disease?

Answer 16

Yes

Question 17

T/F: Drugs are always used in combination to treat tuberculosis

Answer 17

True

Question 18

What are 5 problems of TB treatment?

Answer 18

1. Combo drug therapy needed
2. Limited single drug activity
3. Developed drug resistance
4. Need prolonged treatment
5. Poor drug distribution in walled off lesions

Question 19

What is multi drug resistant TB (MDR-TB)?

Answer 19

Resistant to at least isoniazid and rifampin

Question 20

What is extensively drug resistant TB (EDR-TB)

Answer 20

Resistant to isoniazid and rifampin, plus fluoroquinolone and at least one of three injectable second-line drugs

Question 21

What does Mycobacterium bovis cause?

Answer 21

Zoonotic TB

Question 22

What is the main portal of entry for M. bovis?

Answer 22

GI tract

Question 23

What kind of host range and distribution does M. bovis have?

Answer 23

Wide host range and geographic distribution

Question 24

What kind of infection does M. bovis cause in cattle?

Answer 24

Bovine tuberculosis

Question 25

What is the most common transmission model of M. bovis in cattle?

Answer 25

Aerosol

Question 26

What are some lesions of M. bovis?

Answer 26

Enlarged regional lymph nodes and generalized wasting in advanced disease stage

Question 27

How would you DX bovine tuberculosis?

Answer 27

Tuberculin test Direct acid fast Culture DNA-based methods / PCR Clinical disease + histopathology

Question 28

What is a tuberculin hypersensitivity skin test?

Answer 28

Screening test in caudal tail fold; read reaction at injection site 72 hours after

Question 29

What type of lesions would be seen with Tb?

Answer 29

Caseous necrosis Granulomatous inflammation Multinucleate giant cells Macrophages and lymphocytes

Question 30

Is therapy for TB in cattle recommended?

Answer 30

No

Question 31

Are there vaccines for TB in cattle?

Answer 31

No

Question 32

What disease does M. avian subsp. paratuberculosis cause?

Answer 32

Johne's disease or paratuberculosis

Question 33

What is Johne's disease?

Answer 33

A chronic, progressive granulomatous enteritis

Question 34

Who is the primary host for Johne's disease?

Answer 34

Ruminants (cattle)

Question 35

If you suspect Johne's infection in mother, what should happen to the calf?

Answer 35

Remove from mother and feed colostrum

Question 36

What is the "iceberg effect" for paratuberculosis?

Answer 36

If one clinical animal is detected, many cases of subclinical animals exist

Question 37

What are the symptoms of Johne's disease?

Answer 37

Diarrhea and weight loss bc there is no absorption of nutrients due to caseous granulomas in mucosa

Question 38

What is the main DX method for paratuberculosis?

Answer 38

Serology-Ab detection

Question 39

What are two ways to detect host response to paratuberculosis infection?

Answer 39

1. Humoral Immune response | 2. Cell mediated immune response - Johnin hypersensitivity skin test

Question 40

Why are vaccines for Johne's disease restricted?

Answer 40

Vaccines highly reactive

Question 41

T/F: M. paratuberculosis has a role in Human Crohn's disease

Answer 41

True

Question 42

What does Mycobacterium avian complex (MAC) cause?

Answer 42

Avian tuberculosis

Question 43

How can MAC spread?

Answer 43

Wide spread in soil, water, including treated municipal tap water

Question 44

What does Mycobacterium ulcers cause?

Answer 44

Buruli ulcer

Question 45

What does Mycobacterium leprae cause?

Answer 45

Leprosy or Hansen's disease

Question 46

What is the only know animal reservoir for M. leprae?

Answer 46

Nine banded Armadillo in southern US

Question 47

What is tuberculoid leprosy?

Answer 47

Few acid positive bacilli in lesion

Question 48

What is lepromatous leprosy?

Answer 48

No cell mediated response, severe disease with numerous acid fast + bacilli

Question 49

What does Mycobacterium lepraemurium cause?

Answer 49

Feline and murine leprosy

Question 50

What is seen with feline and murine leprosy?

Answer 50

Granulomatous dermatitis panniculitis Leproid granulomas

Question 51

What is seen in DX of M. lepraemurium?

Answer 51

In geimsa or gram stain, will see negative stained bacilli

Question 52

How would you TX Leprosy in dogs?

Answer 52

Doxycycline can be effective

Question 53

What kind of host response is seen with Saprophytic Mycobacterial spp?

Answer 53

Granulomatous pyogranulomatous host response

Question 54

What is seen with Saprophytic Mycobacterial spp?

Answer 54

Chronic, non-healing cutaneous lesions and lack of response to common antimicrobial treatments