5.3 Gram Positive Rods 2

Question 1

what is a feature of the “anatomy” of the mycolata group of bacteria?

Answer 1

they have a lipid rich outer membrane containing mycolic acid

Question 2

What bacteria are in the mycolata group?

Answer 2

corynebacterium, mycobacterium, rhodococcus

Question 3

all mycolata are what type of pathogens and what do they like?

Answer 3

facultative intracellular; like macrophages

Question 4

all mycolata (corynebacterium, mycobacterium, rhodococcus) cause ______________ inflammation, which involves a ___________ immune response

Answer 4

granulomatous; type 1

Question 5

what species do corynebacteria infect

Answer 5

humans, ruminants, other animals

Question 6

what species do mycobacterium infect

Answer 6

humans, birds, ruminants, horses, pigs

Question 7

what species do rhodococcus infect

Answer 7

herbivores

Question 8

what is an important disease in small ruminants caused by corynebacterium, and what specific species is the bacteria

Answer 8

corynebacterium pseudotuberculosis causes caseous lymphadenitis

Question 9

what is the causative agent of caseous lymphadenitis

Answer 9

corynebacterium pseudotuberculosis

Question 10

what shape do corynebacterium spp. take

Answer 10

pleomorphic: rods, cocci, clubs

Question 11

corynebacterium are commensals of (2)

Answer 11

skin and mm

Question 12

what type of infection (appearance) do corynebacterium cause

Answer 12

pyogenic

Question 13

what are 2 important tests to diagnose C. pseudotuberculosis

Answer 13

gamma interferon test and serology

Question 14

what is the purpose of the gamma interferon test

Answer 14

checks for a type 1 cellular immunity response, characteristic of mycolata

Question 15

T/F C. pseudotuberculosis is contagious and zoonotic

Answer 15

T

Question 16

what is the typical “structure” of C. pseudotuberculosis lesions

Answer 16

caseous lymphadenitis with an onion ring structure

Question 17

what is the consequence of in vitro vs in vivo antibiotic use against corynebacterium

Answer 17

in vitro effective but in vivo problematic due to intracellular nature of pathogen and poor penetration of granulomas

Question 18

describe the vaccine against corynebacterium

Answer 18

poor efficacy and major side effects such as microabscessation

Question 19

how do we control corynebacterium infection

Answer 19

culling based on blood test results

Question 20

how does mycobacterium stain and what does this mean

Answer 20

weakly gram positive, requires acid-fast stain to see

Question 21

mycobacterium spp. survive well or poorly in the environment

Answer 21

well, but slow growing

Question 22

what type of infections do mycobacterium spp. cause

Answer 22

chronic granulomatous infections

Question 23

T/F domestic animal species are susceptible to M. tuberculosis

Answer 23

F; only humans and primates

Question 24

what species are susceptible to M. bovis

Answer 24

ruminants, humans, horses, pigs

Question 25

what species are susceptible to M. avium subsp. paratuberculosis

Answer 25

ruminants

Question 26

T/F M. bovis is reportable and zoonotic

Answer 26

T

Question 27

what is the major implication of wildlife species being infected with M. bovis

Answer 27

wildlife reservoir

Question 28

What causes tuberculosis disease in humans vs animals?

Answer 28

Mycobacterium bovis in animals vs mycobacterium tuberculosis in human

Question 29

describe the pathogenesis of tuberculosis from M. bovis

Answer 29

1. starts with inhalation of infectious particles 2. infect lungs 3. infect **pulmonary macrophage** 4. infected macrophage migrates to local **LN** 5. from there innate control results in either **healing or acute disease or containment** 6. from containment (i.e. granuloma) the disease becomes **latent** 7. <10% of the time it **reactivates** and then can cause disease and spread

Question 30

what type of cellular response is induced by tuberculosis (M. bovis for example)

Answer 30

TH1 response with: * IFN-γ * Macrophage activation * Cytotoxic T cells

Question 31

how is M. bovis **usually** diagnosed

Answer 31

at slaughter using the tuberculin test; then traced back to farm and the remaining animals are tested

Question 32

if you wanted to examine a tissue sample for M. bovis, how would you stain it

Answer 32

using acid-fast

Question 33

why is culture not a great option to diagnose bovine tuberculosis caused by M. bovis and what is a better detection method in this case

Answer 33

slow culture; DNA-based methods (or staining or tuberculin test)

Question 34

what is the treatment for M. bovis

Answer 34

culling

Question 35

where does M. bovis persist in Canada? what other gram-positive aerobic bacteria is also endemic to this area?

Answer 35

Wood Buffalo National Park (AB); Bacillus anthracis

Question 36

T/F avian tuberculosis is zoonotic

Answer 36

T

Question 37

what is the causative agent of avian tuberculosis

Answer 37

Mycobacterium avium subsp. avium, MAC

Question 38

in what ways is avian tuberculosis similar to bovine tuberculosis

Answer 38

entry by air, chronic infection, granulomatous

Question 39

T/F Johne's disease is zoonotic

Answer 39

T

Question 40

what is the causative agent of Johne's disease

Answer 40

Mycobacterium avium subsp. paratuberculosis

Question 41

how does M. avium subsp. paratuberculosis like to grow

Answer 41

on lipid rich media

Question 42

how do we visualize M. avium subsp. paratuberculosis (what stain)

Answer 42

acid-fast stain

Question 43

how is Johne's spread

Answer 43

milk, pasture, in utero

Question 44

what does M. avium subsp. paratuberculosis cause

Answer 44

Johne's: granulomatous enteritis, cachexia, diarrhea

Question 45

If you diagnose an animal with M. avium subsp. paratuberculosis (Johne's) why would you immediately shit yourself

Answer 45

because if there are clinical animals in the herd there are way more (60%) subclinical animals also present in the herd that are shedding the bacteria... you're fucked

Question 46

T/F there is a genetic predisposition to Johne's

Answer 46

T

Question 47

how do we treat and prevent Johne's

Answer 47

culling of infected and sick animals; detecting and culling subclinical shedders using serology and gamma interferon test

Question 48

how do rhodococcus stain

Answer 48

gram positive and slightly acid-fast

Question 49

T/F R. equi is zoonotic and reportable

Answer 49

F; zoonotic but not reportable

Question 50

what does R. equi cause in foals

Answer 50

pyogranulomatous bronchopneumonia

Question 51

what is the epidemiology of R. equi in foals

Answer 51

associated with heavy contamination of the environment and susceptibility is highest when maternal antibodies are waning

Question 52

what is unique about the virulence of R. equi

Answer 52

contains virulence plasmids

Question 53

how do virulent strains of R. equi influence the immune response

Answer 53

infect and survive in macrophages, but macrophages are required to induce a type 1 immune response to kill the bacteria; it also downregulates TH1 cells and can drive an inappropriate TH2 response

Question 54

how do you treat R. equi

Answer 54

long term treatment with rifampin and macrolides

Question 55

how do you prevent R. equi

Answer 55

dust control; colostrum; reduced manure load

Question 56

how would a laboratory confirm a suspected case of tuberculosis

Answer 56

PCR, acid-fast staining of tissue, culture (slow)

Question 57

how could you assess whether live animals on a farm were exposed to M. bovis

Answer 57

whole blood gamma interferon test

Question 58

T/F if you detect caseous lymphadenitis you should treat with antibiotics

Answer 58

F; there will be poor penetration of the antibiotics so it is a waste